All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.
The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.
New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time. Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.
The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.
Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.
Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.
===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
// but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}
@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}
@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}
@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
*off = E
|
*off += E
|
func(..., off, ...)
|
E = *off
)
...+>
}
@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}
@ fops0 @
identifier fops;
@@
struct file_operations fops = {
...
};
@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
.llseek = llseek_f,
...
};
@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
.read = read_f,
...
};
@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
.write = write_f,
...
};
@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
.open = open_f,
...
};
// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
... .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};
@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
... .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};
// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
... .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};
// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};
// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};
@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+ .llseek = default_llseek, /* write accesses f_pos */
};
// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////
@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
.write = write_f,
.read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};
@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};
@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};
@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
The semctl syscall has several code paths that lead to the leakage of
uninitialized kernel stack memory (namely the IPC_INFO, SEM_INFO,
IPC_STAT, and SEM_STAT commands) during the use of the older, obsolete
version of the semid_ds struct.
The copy_semid_to_user() function declares a semid_ds struct on the stack
and copies it back to the user without initializing or zeroing the
"sem_base", "sem_pending", "sem_pending_last", and "undo" pointers,
allowing the leakage of 16 bytes of kernel stack memory.
The code is still reachable on 32-bit systems - when calling semctl()
newer glibc's automatically OR the IPC command with the IPC_64 flag, but
invoking the syscall directly allows users to use the older versions of
the struct.
Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The last change to improve the scalability moved the actual wake-up out of
the section that is protected by spin_lock(sma->sem_perm.lock).
This means that IN_WAKEUP can be in queue.status even when the spinlock is
acquired by the current task. Thus the same loop that is performed when
queue.status is read without the spinlock acquired must be performed when
the spinlock is acquired.
Thanks to kamezawa.hiroyu@jp.fujitsu.com for noticing lack of the memory
barrier.
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=16255
[akpm@linux-foundation.org: clean up kerneldoc, checkpatch warning and whitespace]
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Reported-by: Luca Tettamanti <kronos.it@gmail.com>
Tested-by: Luca Tettamanti <kronos.it@gmail.com>
Reported-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Maciej Rutecki <maciej.rutecki@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It never hashes them anyway and does final iput() immediately
afterwards. With ->drop_inode() being generic_delete_inode()...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use ERR_CAST(x) rather than ERR_PTR(PTR_ERR(x)). The former makes more
clear what is the purpose of the operation, which otherwise looks like a
no-op.
The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
type T;
T x;
identifier f;
@@
T f (...) { <+...
- ERR_PTR(PTR_ERR(x))
+ x
...+> }
@@
expression x;
@@
- ERR_PTR(PTR_ERR(x))
+ ERR_CAST(x)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ipc/sem.c begins with a 15 year old description about bugs in the initial
implementation in Linux-1.0. The patch replaces that with a top level
description of the current code.
A TODO could be derived from this text:
The opengroup man page for semop() does not mandate FIFO. Thus there is
no need for a semaphore array list of pending operations.
If
- this list is removed
- the per-semaphore array spinlock is removed (possible if there is no
list to protect)
- sem_otime is moved into the semaphores and calculated on demand during
semctl()
then the array would be read-mostly - which would significantly improve
scaling for applications that use semaphore arrays with lots of entries.
The price would be expensive semctl() calls:
for(i=0;i<sma->sem_nsems;i++) spin_lock(sma->sem_lock);
<do stuff>
for(i=0;i<sma->sem_nsems;i++) spin_unlock(sma->sem_lock);
I'm not sure if the complexity is worth the effort, thus here is the
documentation of the current behavior first.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The wake-up part of semtimedop() consists out of two steps:
- the right tasks must be identified.
- they must be woken up.
Right now, both steps run while the array spinlock is held. This patch
reorders the code and moves the actual wake_up_process() behind the point
where the spinlock is dropped.
The code also moves setting sem->sem_otime to one place: It does not make
sense to set the last modify time multiple times.
[akpm@linux-foundation.org: repair kerneldoc]
[akpm@linux-foundation.org: fix uninitialised retval]
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The following series of patches tries to fix the spinlock contention
reported by Chris Mason - his benchmark exposes problems of the current
code:
- In the worst case, the algorithm used by update_queue() is O(N^2).
Bulk wake-up calls can enter this worst case. The patch series fix
that.
Note that the benchmark app doesn't expose the problem, it just should
be fixed: Real world apps might do the wake-ups in another order than
perfect FIFO.
- The part of the code that runs within the semaphore array spinlock is
significantly larger than necessary.
The patch series fixes that. This change is responsible for the main
improvement.
- The cacheline with the spinlock is also used for a variable that is
read in the hot path (sem_base) and for a variable that is unnecessarily
written to multiple times (sem_otime). The last step of the series
cacheline-aligns the spinlock.
This patch:
The SysV semaphore code allows to perform multiple operations on all
semaphores in the array as atomic operations. After a modification,
update_queue() checks which of the waiting tasks can complete.
The algorithm that is used to identify the tasks is O(N^2) in the worst
case. For some cases, it is simple to avoid the O(N^2).
The patch adds a detection logic for some cases, especially for the case
of an array where all sleeping tasks are single sembuf operations and a
multi-sembuf operation is used to wake up multiple tasks.
A big database application uses that approach.
The patch fixes wakeup due to semctl(,,SETALL,) - the initial version of
the patch breaks that.
[akpm@linux-foundation.org: make do_smart_update() static]
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- C99 knows about USHRT_MAX/SHRT_MAX/SHRT_MIN, not
USHORT_MAX/SHORT_MAX/SHORT_MIN.
- Make SHRT_MIN of type s16, not int, for consistency.
[akpm@linux-foundation.org: fix drivers/dma/timb_dma.c]
[akpm@linux-foundation.org: fix security/keys/keyring.c]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
clocksource: Add clocksource_register_hz/khz interface
posix-cpu-timers: Optimize run_posix_cpu_timers()
time: Remove xtime_cache
mqueue: Convert message queue timeout to use hrtimers
hrtimers: Provide schedule_hrtimeout for CLOCK_REALTIME
timers: Introduce the concept of timer slack for legacy timers
ntp: Remove tickadj
ntp: Make time_adjust static
time: Add xtime, wall_to_monotonic to feature-removal-schedule
timer: Try to survive timer callback preempt_count leak
timer: Split out timer function call
timer: Print function name for timer callbacks modifying preemption count
time: Clean up warp_clock()
cpu-timers: Avoid iterating over all threads in fastpath_timer_check()
cpu-timers: Change SIGEV_NONE timer implementation
cpu-timers: Return correct previous timer reload value
cpu-timers: Cleanup arm_timer()
cpu-timers: Simplify RLIMIT_CPU handling
In case of aborting because we reach the maximum amount of memory which
can be allocated to message queues per user (RLIMIT_MSGQUEUE), we would
try to free the message area twice when bailing out: first by the error
handling code itself, and then later when cleaning up the inode through
delete_inode().
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The message queue functions mq_timedsend() and mq_timedreceive()
have not yet been converted to use the hrtimer interface.
This patch replaces the call to schedule_timeout() by a call to
schedule_hrtimeout() and transforms the expiration time from
timespec to ktime as required.
[ tglx: Fixed whitespace wreckage ]
Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Tested-by: Pradyumna Sampath <pradysam@gmail.com>
Cc: Arjan van de Veen <arjan@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <20100402204331.715783034@osadl.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
I chased down a fail on ppc64 on 2.6.34-rc2 where an application that
uses shared memory was getting a SEGV.
Commit baed7fc9b5 ("Add generic sys_ipc
wrapper") changed the second argument from an unsigned long to an int.
When we call shmget the system call wrappers for sys_ipc will sign
extend second (ie the size) which truncates it. It took a while to
track down because the call succeeds and strace shows the untruncated
size :)
The patch below changes second from an int to an unsigned long which
fixes shmget on ppc64 (and I assume s390, sparc64 and mips64).
Signed-off-by: Anton Blanchard <anton@samba.org>
--
I assume the function prototypes for the other IPC methods would cause us
to sign or zero extend second where appropriate (avoiding any security
issues). Come to think of it, the syscall wrappers for each method should do
that for us as well.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make sure compiler won't do weird things with limits. E.g. fetching them
twice may return 2 different values after writable limits are implemented.
I.e. either use rlimit helpers added in
3e10e716ab ("resource: add helpers for
fetching rlimits") or ACCESS_ONCE if not applicable.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a generic implementation of the ipc demultiplexer syscall. Except for
s390 and sparc64 all implementations of the sys_ipc are nearly identical.
There are slight differences in the types of the parameters, where mips
and powerpc as the only 64-bit architectures with sys_ipc use unsigned
long for the "third" argument as it gets casted to a pointer later, while
it traditionally is an "int" like most other paramters. frv goes even
further and uses unsigned long for all parameters execept for "ptr" which
is a pointer type everywhere. The change from int to unsigned long for
"third" and back to "int" for the others on frv should be fine due to the
in-register calling conventions for syscalls (we already had a similar
issue with the generic sys_ptrace), but I'd prefer to have the arch
maintainers looks over this in details.
Except for that h8300, m68k and m68knommu lack an impplementation of the
semtimedop sub call which this patch adds, and various architectures have
gets used - at least on i386 it seems superflous as the compat code on
x86-64 and ia64 doesn't even bother to implement it.
[akpm@linux-foundation.org: add sys_ipc to sys_ni.c]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Reviewed-by: H. Peter Anvin <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
... postponing assignments until they're needed. Doesn't change code size.
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
It reduces code size:
text data bss dec hex filename
9925 72 16 10013 271d ipc/mqueue-BEFORE.o
9885 72 16 9973 26f5 ipc/mqueue-AFTER.o
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Code size reduction:
text data bss dec hex filename
9941 72 16 10029 272d ipc/mqueue-BEFORE.o
9925 72 16 10013 271d ipc/mqueue-AFTER.o
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... and abort earlier if we couldn't allocate the message pointers array,
avoiding the u->mq_bytes accounting logic.
It reduces code size:
text data bss dec hex filename
9949 72 16 10037 2735 ipc/mqueue-BEFORE.o
9941 72 16 10029 272d ipc/mqueue-AFTER.o
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Commit c4caa77815 ("file
->get_unmapped_area() shouldn't duplicate work of get_unmapped_area()")
broke SYSV SHM for NOMMU by taking away the pointer to
shm_get_unmapped_area() from shm_file_operations.
Put it back conditionally on CONFIG_MMU=n.
file->f_ops->get_unmapped_area() is used to find out the base address for a
mapping of a mappable chardev device or mappable memory-based file (such as a
ramfs file). It needs to be called prior to file->f_ops->mmap() being called.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (38 commits)
direct I/O fallback sync simplification
ocfs: stop using do_sync_mapping_range
cleanup blockdev_direct_IO locking
make generic_acl slightly more generic
sanitize xattr handler prototypes
libfs: move EXPORT_SYMBOL for d_alloc_name
vfs: force reval of target when following LAST_BIND symlinks (try #7)
ima: limit imbalance msg
Untangling ima mess, part 3: kill dead code in ima
Untangling ima mess, part 2: deal with counters
Untangling ima mess, part 1: alloc_file()
O_TRUNC open shouldn't fail after file truncation
ima: call ima_inode_free ima_inode_free
IMA: clean up the IMA counts updating code
ima: only insert at inode creation time
ima: valid return code from ima_inode_alloc
fs: move get_empty_filp() deffinition to internal.h
Sanitize exec_permission_lite()
Kill cached_lookup() and real_lookup()
Kill path_lookup_open()
...
Trivial conflicts in fs/direct-io.c
* do ima_get_count() in __dentry_open()
* stop doing that in followups
* move ima_path_check() to right after nameidata_to_filp()
* don't bump counters on it
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
There are 2 groups of alloc_file() callers:
* ones that are followed by ima_counts_get
* ones giving non-regular files
So let's pull that ima_counts_get() into alloc_file();
it's a no-op in case of non-regular files.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This line is unreachable, remove it.
[akpm@linux-foundation.org: remove unneeded initialisation of `err']
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If multiple simple decrements on the same semaphore are pending, then the
current code scans all decrement operations, even if the semaphore value
is already 0.
The patch optimizes that: if the semaphore value is 0, then there is no
need to scan the q->alter entries.
Note that this is a common case: It happens if 100 decrements by one are
pending and now an increment by one increases the semaphore value from 0
to 1. Without this patch, all 100 entries are scanned. With the patch,
only one entry is scanned, then woken up. Then the new rule triggers and
the scanning is aborted, without looking at the remaining 99 tasks.
With this patch, single sop increment/decrement by 1 are now O(1).
(same as with Nick's patch)
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sysv sem has the concept of semaphore arrays that consist out of multiple
semaphores. Atomic operations that affect multiple semaphores are
supported.
The patch optimizes single semaphore operation calls that affect only one
semaphore: It's not necessary to scan all pending operations, it is
sufficient to scan the per-semaphore list.
The idea is from Nick Piggin version of an ipc sem improvement, the
implementation is different: The code tries to keep as much common code as
possible.
As the result, the patch is simpler, but optimizes fewer cases.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Based on Nick's findings:
sysv sem has the concept of semaphore arrays that consist out of multiple
semaphores. Atomic operations that affect multiple semaphores are
supported.
The patch is the first step for optimizing simple, single semaphore
operations: In addition to the global list of all pending operations, a
2nd, per-semaphore list with the simple operations is added.
Note: this patch does not make sense by itself, the new list is used
nowhere.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reduce the amount of scanning of the list of pending semaphore operations:
If try_atomic_semop failed, then no changes were applied. Thus no need to
restart.
Additionally, this patch correct an incorrect comment: It's possible to
wait for arbitrary semaphore values (do a dec by <x>, wait-for-zero, inc
by <x> in one atomic operation)
Both changes are from Nick Piggin, the patch is the result of a different
split of the individual changes.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The strange sysv semaphore wakeup scheme has a kind of busy-wait lock
involved, which could deadlock if preemption is enabled during the "lock".
It is an implementation detail (due to a spinlock being held) that this is
actually the case. However if "spinlocks" are made preemptible, or if the
sem lock is changed to a sleeping lock for example, then the wakeup would
become buggy. So this might be a bugfix for -rt kernels.
Imagine waker being preempted by wakee and never clearing IN_WAKEUP -- if
wakee has higher RT priority then there is a priority inversion deadlock.
Even if there is not a priority inversion to cause a deadlock, then there
is still time wasted spinning.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace the handcoded list operations in update_queue() with the standard
list_for_each_entry macros.
list_for_each_entry_safe() must be used, because list entries can
disappear immediately uppon the wakeup event.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Around a month ago, there was some discussion about an improvement of the
sysv sem algorithm: Most (at least: some important) users only use simple
semaphore operations, therefore it's worthwile to optimize this use case.
This patch:
Move last looked up sem_undo struct to the head of the task's undo list.
Attempt to move common entries to the front of the list so search time is
reduced. This reduces lookup_undo on oprofile of problematic SAP workload
by 30% (see patch 4 for a description of SAP workload).
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have apparently had a memory leak since
7ca7e564e0 "ipc: store ipcs into IDRs" in
2007. The idr of which 3 exist for each ipc namespace is never freed.
This patch simply frees them when the ipcns is freed. I don't believe any
idr_remove() are done from rcu (and could therefore be delayed until after
this idr_destroy()), so the patch should be safe. Some quick testing
showed no harm, and the memory leak fixed.
Caught by kmemleak.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
... we should call mm ->get_unmapped_area() instead and let our caller
do the final checks.
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Commit a0d092f introduced the following warning:
ipc/msg.c: In function ?msgctl_down?:
ipc/msg.c:415: warning: ?msqid64? may be used uninitialized in this function
The gcc warning in this case is actually bogus, as msqid64 is touched only
iff cmd == IPC_SET, and in such case, copy_msqid_from_user() initializes
it properly.
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Now that sys_sysctl is a generic wrapper around /proc/sys .ctl_name
and .strategy members of sysctl tables are dead code. Remove them.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* mark struct vm_area_struct::vm_ops as const
* mark vm_ops in AGP code
But leave TTM code alone, something is fishy there with global vm_ops
being used.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's unused.
It isn't needed -- read or write flag is already passed and sysctl
shouldn't care about the rest.
It _was_ used in two places at arch/frv for some reason.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make all seq_operations structs const, to help mitigate against
revectoring user-triggerable function pointers.
This is derived from the grsecurity patch, although generated from scratch
because it's simpler than extracting the changes from there.
Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patchset adds a flag to mmap that allows the user to request that an
anonymous mapping be backed with huge pages. This mapping will borrow
functionality from the huge page shm code to create a file on the kernel
internal mount and use it to approximate an anonymous mapping. The
MAP_HUGETLB flag is a modifier to MAP_ANONYMOUS and will not work without
both flags being preset.
A new flag is necessary because there is no other way to hook into huge
pages without creating a file on a hugetlbfs mount which wouldn't be
MAP_ANONYMOUS.
To userspace, this mapping will behave just like an anonymous mapping
because the file is not accessible outside of the kernel.
This patchset is meant to simplify the programming model. Presently there
is a large chunk of boiler platecode, contained in libhugetlbfs, required
to create private, hugepage backed mappings. This patch set would allow
use of hugepages without linking to libhugetlbfs or having hugetblfs
mounted.
Unification of the VM code would provide these same benefits, but it has
been resisted each time that it has been suggested for several reasons: it
would break PAGE_SIZE assumptions across the kernel, it makes page-table
abstractions really expensive, and it does not provide any benefit on
architectures that do not support huge pages, incurring fast path
penalties without providing any benefit on these architectures.
This patch:
There are two means of creating mappings backed by huge pages:
1. mmap() a file created on hugetlbfs
2. Use shm which creates a file on an internal mount which essentially
maps it MAP_SHARED
The internal mount is only used for shared mappings but there is very
little that stops it being used for private mappings. This patch extends
hugetlbfs_file_setup() to deal with the creation of files that will be
mapped MAP_PRIVATE on the internal hugetlbfs mount. This extended API is
used in a subsequent patch to implement the MAP_HUGETLB mmap() flag.
Signed-off-by: Eric Munson <ebmunson@us.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Adam Litke <agl@us.ibm.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
My 353d5c30c6 "mm: fix hugetlb bug due to
user_shm_unlock call" broke the CONFIG_SYSVIPC !CONFIG_MMU build of both
2.6.31 and 2.6.30.6: "undefined reference to `user_shm_unlock'".
gcc didn't understand my comment! so couldn't figure out to optimize
away user_shm_unlock() from the error path in the hugetlb-less case, as
it does elsewhere. Help it to do so, in a language it understands.
Reported-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2.6.30's commit 8a0bdec194 removed
user_shm_lock() calls in hugetlb_file_setup() but left the
user_shm_unlock call in shm_destroy().
In detail:
Assume that can_do_hugetlb_shm() returns true and hence user_shm_lock()
is not called in hugetlb_file_setup(). However, user_shm_unlock() is
called in any case in shm_destroy() and in the following
atomic_dec_and_lock(&up->__count) in free_uid() is executed and if
up->__count gets zero, also cleanup_user_struct() is scheduled.
Note that sched_destroy_user() is empty if CONFIG_USER_SCHED is not set.
However, the ref counter up->__count gets unexpectedly non-positive and
the corresponding structs are freed even though there are live
references to them, resulting in a kernel oops after a lots of
shmget(SHM_HUGETLB)/shmctl(IPC_RMID) cycles and CONFIG_USER_SCHED set.
Hugh changed Stefan's suggested patch: can_do_hugetlb_shm() at the
time of shm_destroy() may give a different answer from at the time
of hugetlb_file_setup(). And fixed newseg()'s no_id error path,
which has missed user_shm_unlock() ever since it came in 2.6.9.
Reported-by: Stefan Huber <shuber2@gmail.com>
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Tested-by: Stefan Huber <shuber2@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch fixes an imbalance message as reported by Sanchin Sant.
As we don't need to measure the message queue, just increment the
counters.
Reported-by: Sanchin Sant <sanchinp@in.ibm.com>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
31a985f "ipc: use __ARCH_WANT_IPC_PARSE_VERSION in ipc/util.h" would
choose the implementation of ipc_parse_version() based on a symbol
defined in <asm/unistd.h>.
But it failed to also include this header and thus broke
IPC_64-passing 32-bit userspace because the flag wasn't masked out
properly anymore and the command not understood.
Include <linux/unistd.h> to give the architecture a chance to ask for
the no-no-op ipc_parse_version().
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Function is really private to ipc/ and avoid struct kern_ipc_perm
forward declaration.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
clone_ipc_ns() is misnamed, it doesn't clone anything and doesn't use
passed parameter. Rename it.
create_ipc_ns() will be used by C/R to create fresh ipcns.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
copy_ipcs() doesn't actually copy anything. If new ipcns is created, it's
created from scratch, in this case get/put on old ipcns isn't needed.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The definition of ipc_parse_version depends on
__ARCH_WANT_IPC_PARSE_VERSION, but the header file declares it
conditionally based on the architecture.
Use the macro consistently to make it easier to add new architectures.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: rcu_sched_grace_period(): kill the bogus flush_signals()
rculist: use list_entry_rcu in places where it's appropriate
rculist.h: introduce list_entry_rcu() and list_first_entry_rcu()
rcu: Update RCU tracing documentation for __rcu_pending
rcu: Add __rcu_pending tracing to hierarchical RCU
RCU: make treercu be default
The massive nommu update (8feae131) resulted in these warnings:
ipc/shm.c: In function `sys_shmdt':
ipc/shm.c:974: warning: unused variable `size'
ipc/shm.c:972: warning: unused variable `next'
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Based on discussion on lkml (Andrew Morton and Eric Paris),
move ima_counts_get down a layer into shmem/hugetlb__file_setup().
Resolves drm shmem_file_setup() usage case as well.
HD comment:
I still think you're doing this at the wrong level, but recognize
that you probably won't be persuaded until a few more users of
alloc_file() emerge, all wanting your ima_counts_get().
Resolving GEM's shmem_file_setup() is an improvement, so I'll say
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
- Add support in ima_path_check() for integrity checking without
incrementing the counts. (Required for nfsd.)
- rename and export opencount_get to ima_counts_get
- replace ima_shm_check calls with ima_counts_get
- export ima_path_check
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
| ipc/mq_sysctl.c:26: warning: 'get_mq' defined but not used
Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Largely inspired from ipc/ipc_sysctl.c. This patch isolates the mqueue
sysctl stuff in its own file.
[akpm@linux-foundation.org: build fix]
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implement multiple mounts of the mqueue file system, and link it to usage
of CLONE_NEWIPC.
Each ipc ns has a corresponding mqueuefs superblock. When a user does
clone(CLONE_NEWIPC) or unshare(CLONE_NEWIPC), the unshare will cause an
internal mount of a new mqueuefs sb linked to the new ipc ns.
When a user does 'mount -t mqueue mqueue /dev/mqueue', he mounts the
mqueuefs superblock.
Posix message queues can be worked with both through the mq_* system calls
(see mq_overview(7)), and through the VFS through the mqueue mount. Any
usage of mq_open() and friends will work with the acting task's ipc
namespace. Any actions through the VFS will work with the mqueuefs in
which the file was created. So if a user doesn't remount mqueuefs after
unshare(CLONE_NEWIPC), mq_open("/ab") will not be reflected in "ls
/dev/mqueue".
If task a mounts mqueue for ipc_ns:1, then clones task b with a new ipcns,
ipcns:2, and then task a is the last task in ipc_ns:1 to exit, then (1)
ipc_ns:1 will be freed, (2) it's superblock will live on until task b
umounts the corresponding mqueuefs, and vfs actions will continue to
succeed, but (3) sb->s_fs_info will be NULL for the sb corresponding to
the deceased ipc_ns:1.
To make this happen, we must protect the ipc reference count when
a) a task exits and drops its ipcns->count, since it might be dropping
it to 0 and freeing the ipcns
b) a task accesses the ipcns through its mqueuefs interface, since it
bumps the ipcns refcount and might race with the last task in the ipcns
exiting.
So the kref is changed to an atomic_t so we can use
atomic_dec_and_lock(&ns->count,mq_lock), and every access to the ipcns
through ns = mqueuefs_sb->s_fs_info is protected by the same lock.
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move mqueue vfsmount plus a few tunables into the ipc_namespace struct.
The CONFIG_IPC_NS boolean and the ipc_namespace struct will serve both the
posix message queue namespaces and the SYSV ipc namespaces.
The sysctl code will be fixed separately in patch 3. After just this
patch, making a change to posix mqueue tunables always changes the values
in the initial ipc namespace.
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
Remove two unneeded exports and make two symbols static in fs/mpage.c
Cleanup after commit 585d3bc06f
Trim includes of fdtable.h
Don't crap into descriptor table in binfmt_som
Trim includes in binfmt_elf
Don't mess with descriptor table in load_elf_binary()
Get rid of indirect include of fs_struct.h
New helper - current_umask()
check_unsafe_exec() doesn't care about signal handlers sharing
New locking/refcounting for fs_struct
Take fs_struct handling to new file (fs/fs_struct.c)
Get rid of bumping fs_struct refcount in pivot_root(2)
Kill unsharing fs_struct in __set_personality()
As pointed out by Cedric Le Goater (in response to Alexey's original
comment wrt mqns), ipc_sysctl.c and utsname_sysctl.c are using
CONFIG_PROC_FS, not CONFIG_PROC_SYSCTL, to determine whether to define
the proc_handlers. Change that.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Acked-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
shm_get_stat() assumes idr_find(&shm_ids(ns).ipcs_idr) returns "struct
shmid_kernel *"; all other callers assume that it returns "struct
kern_ipc_perm *". This works because "struct kern_ipc_perm" is currently
the first member of "struct shmid_kernel", but it would be better to use
container_of() to prevent future breakage.
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Cc: Jiri Olsa <olsajiri@gmail.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'bkl-removal' of git://git.lwn.net/linux-2.6:
Rationalize fasync return values
Move FASYNC bit handling to f_op->fasync()
Use f_lock to protect f_flags
Rename struct file->f_ep_lock
Traditionally, changes to struct file->f_flags have been done under BKL
protection, or with no protection at all. This patch causes all f_flags
changes after file open/creation time to be done under protection of
f_lock. This allows the removal of some BKL usage and fixes a number of
longstanding (if microscopic) races.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
When overcommit is disabled, the core VM accounts for pages used by anonymous
shared, private mappings and special mappings. It keeps track of VMAs that
should be accounted for with VM_ACCOUNT and VMAs that never had a reserve
with VM_NORESERVE.
Overcommit for hugetlbfs is much riskier than overcommit for base pages
due to contiguity requirements. It avoids overcommiting on both shared and
private mappings using reservation counters that are checked and updated
during mmap(). This ensures (within limits) that hugepages exist in the
future when faults occurs or it is too easy to applications to be SIGKILLed.
As hugetlbfs makes its own reservations of a different unit to the base page
size, VM_ACCOUNT should never be set. Even if the units were correct, we would
double account for the usage in the core VM and hugetlbfs. VM_NORESERVE may
be set because an application can request no reserves be made for hugetlbfs
at the risk of getting killed later.
With commit fc8744adc8, VM_NORESERVE and
VM_ACCOUNT are getting unconditionally set for hugetlbfs-backed mappings. This
breaks the accounting for both the core VM and hugetlbfs, can trigger an
OOM storm when hugepage pools are too small lockups and corrupted counters
otherwise are used. This patch brings hugetlbfs more in line with how the
core VM treats VM_NORESERVE but prevents VM_ACCOUNT being set.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The number of calls to ima_path_check()/ima_file_free()
should be balanced. An extra call to fput(), indicates
the file could have been accessed without first being
measured.
Although f_count is incremented/decremented in places other
than fget/fput, like fget_light/fput_light and get_file, the
current task must already hold a file refcnt. The call to
__fput() is delayed until the refcnt becomes 0, resulting
in ima_file_free() flagging any changes.
- add hook to increment opencount for IPC shared memory(SYSV),
shmat files, and /dev/zero
- moved NULL iint test in opencount_get()
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
shm_get_stat() assumes that the inode is a "struct shmem_inode_info",
which is incorrect for !CONFIG_SHMEM (see fs/ramfs/inode.c:
ramfs_get_inode() vs. mm/shmem.c: shmem_get_inode()).
This bad assumption can cause shmctl(SHM_INFO) to lockup when
shm_get_stat() tries to spin_lock(&info->lock). Users of !CONFIG_SHMEM
may encounter this lockup simply by invoking the 'ipcs' command.
Reported by Jiri Olsa back in February 2008:
http://lkml.org/lkml/2008/2/29/74
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Reported-by: Jiri Olsa <olsajiri@gmail.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: <stable@kernel.org> [2.6.everything]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The mmap_region() code would temporarily set the VM_ACCOUNT flag for
anonymous shared mappings just to inform shmem_zero_setup() that it
should enable accounting for the resulting shm object. It would then
clear the flag after calling ->mmap (for the /dev/zero case) or doing
shmem_zero_setup() (for the MAP_ANON case).
This just resulted in vma merge issues, but also made for just
unnecessary confusion. Use the already-existing VM_NORESERVE flag for
this instead, and let shmem_{zero|file}_setup() just figure it out from
that.
This also happens to make it obvious that the new DRI2 GEM layer uses a
non-reserving backing store for its object allocation - which is quite
possibly not intentional. But since I didn't want to change semantics
in this patch, I left it alone, and just updated the caller to use the
new flag semantics.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
System calls with an unsigned long long argument can't be converted with
the standard wrappers since that would include a cast to long, which in
turn means that we would lose the upper 32 bit on 32 bit architectures.
Also semctl can't use the standard wrapper since it has a 'union'
parameter.
So we handle them as special case and add some extra wrappers instead.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Convert all system calls to return a long. This should be a NOP since all
converted types should have the same size anyway.
With the exception of sys_exit_group which returned void. But that doesn't
matter since the system call doesn't return.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-nommu:
NOMMU: Support XIP on initramfs
NOMMU: Teach kobjsize() about VMA regions.
FLAT: Don't attempt to expand the userspace stack to fill the space allocated
FDPIC: Don't attempt to expand the userspace stack to fill the space allocated
NOMMU: Improve procfs output using per-MM VMAs
NOMMU: Make mmap allocation page trimming behaviour configurable.
NOMMU: Make VMAs per MM as for MMU-mode linux
NOMMU: Delete askedalloc and realalloc variables
NOMMU: Rename ARM's struct vm_region
NOMMU: Fix cleanup handling in ramfs_nommu_get_umapped_area()
If a process registers for asynchronous notification on a POSIX message
queue, it gets a signal and a siginfo_t structure when a message arrives
on the message queue. The si_pid in the siginfo_t structure is set to the
PID of the process that sent the message to the message queue.
The principle is the following:
. when mq_notify(SIGEV_SIGNAL) is called, the caller registers for
notification when a msg arrives. The associated pid structure is stroed into
inode_info->notify_owner. Let's call this process P1.
. when mq_send() is called by say P2, P2 sends a signal to P1 to notify
him about msg arrival.
The way .si_pid is set today is not correct, since it doesn't take into account
the fact that the process that is sending the message might not be in the
same namespace as the notified one.
This patch proposes to set si_pid to the sender's pid into the notify_owner
namespace.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Bastian Blank <bastian@waldi.eu.org>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make VMAs per mm_struct as for MMU-mode linux. This solves two problems:
(1) In SYSV SHM where nattch for a segment does not reflect the number of
shmat's (and forks) done.
(2) In mmap() where the VMA's vm_mm is set to point to the parent mm by an
exec'ing process when VM_EXECUTABLE is specified, regardless of the fact
that a VMA might be shared and already have its vm_mm assigned to another
process or a dead process.
A new struct (vm_region) is introduced to track a mapped region and to remember
the circumstances under which it may be shared and the vm_list_struct structure
is discarded as it's no longer required.
This patch makes the following additional changes:
(1) Regions are now allocated with alloc_pages() rather than kmalloc() and
with no recourse to __GFP_COMP, so the pages are not composite. Instead,
each page has a reference on it held by the region. Anything else that is
interested in such a page will have to get a reference on it to retain it.
When the pages are released due to unmapping, each page is passed to
put_page() and will be freed when the page usage count reaches zero.
(2) Excess pages are trimmed after an allocation as the allocation must be
made as a power-of-2 quantity of pages.
(3) VMAs are added to the parent MM's R/B tree and mmap lists. As an MM may
end up with overlapping VMAs within the tree, the VMA struct address is
appended to the sort key.
(4) Non-anonymous VMAs are now added to the backing inode's prio list.
(5) Holes may be punched in anonymous VMAs with munmap(), releasing parts of
the backing region. The VMA and region structs will be split if
necessary.
(6) sys_shmdt() only releases one attachment to a SYSV IPC shared memory
segment instead of all the attachments at that addresss. Multiple
shmat()'s return the same address under NOMMU-mode instead of different
virtual addresses as under MMU-mode.
(7) Core dumping for ELF-FDPIC requires fewer exceptions for NOMMU-mode.
(8) /proc/maps is now the global list of mapped regions, and may list bits
that aren't actually mapped anywhere.
(9) /proc/meminfo gains a line (tagged "MmapCopy") that indicates the amount
of RAM currently allocated by mmap to hold mappable regions that can't be
mapped directly. These are copies of the backing device or file if not
anonymous.
These changes make NOMMU mode more similar to MMU mode. The downside is that
NOMMU mode requires some extra memory to track things over NOMMU without this
patch (VMAs are no longer shared, and there are now region structs).
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Mike Frysinger <vapier.adi@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
proc_ipcauto_dointvec_minmax() is the only user of ipc_auto_callback(),
since the former function is protected by CONFIG_PROC_FS, so should be the
latter one.
Just move its definition down.
Signed-off-by: WANG Cong <wangcong@zeuux.org>
Cc: Eric Biederman <ebiederm@xmision.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the macro shm_ids().
Remove useless check for a userspace pointer, because copy_to_user()
will check it.
Some style cleanups.
Signed-off-by: WANG Cong <wangcong@zeuux.org>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
inotify: fix type errors in interfaces
fix breakage in reiserfs_new_inode()
fix the treatment of jfs special inodes
vfs: remove duplicate code in get_fs_type()
add a vfs_fsync helper
sys_execve and sys_uselib do not call into fsnotify
zero i_uid/i_gid on inode allocation
inode->i_op is never NULL
ntfs: don't NULL i_op
isofs check for NULL ->i_op in root directory is dead code
affs: do not zero ->i_op
kill suid bit only for regular files
vfs: lseek(fd, 0, SEEK_CUR) race condition
... and don't bother in callers. Don't bother with zeroing i_blocks,
while we are at it - it's already been zeroed.
i_mode is not worth the effort; it has no common default value.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* don't bother with allocations
* don't do double copy_from_user()
* don't duplicate parts of check for audit_dummy_context()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* logging the original value of *msg_prio in mq_timedreceive(2)
is insane - the argument is write-only (i.e. syscall always
ignores the original value and only overwrites it).
* merge __audit_mq_timed{send,receive}
* don't do copy_from_user() twice
* don't mess with allocations in auditsc part
* ... and don't bother checking !audit_enabled and !context in there -
we'd already checked for audit_dummy_context().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* don't copy_from_user() twice
* don't bother with allocations
* don't duplicate parts of audit_dummy_context()
* make it return void
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Conflicts:
fs/nfsd/nfs4recover.c
Manually fixed above to use new creds API functions, e.g.
nfs4_save_creds().
Signed-off-by: James Morris <jmorris@namei.org>
A problem was found while reviewing the code after Bugzilla bug
http://bugzilla.kernel.org/show_bug.cgi?id=11796.
In ipc_addid(), the newly allocated ipc structure is inserted into the
ipcs tree (i.e made visible to readers) without locking it. This is not
correct since its initialization continues after it has been inserted in
the tree.
This patch moves the ipc structure lock initialization + locking before
the actual insertion.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Reported-by: Clement Calmels <cboulte@gmail.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: <stable@kernel.org> [2.6.27.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pass credentials through dentry_open() so that the COW creds patch can have
SELinux's flush_unauthorized_files() pass the appropriate creds back to itself
when it opens its null chardev.
The security_dentry_open() call also now takes a creds pointer, as does the
dentry_open hook in struct security_operations.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
Wrap current->cred and a few other accessors to hide their actual
implementation.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Separate the task security context from task_struct. At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.
Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.
With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.
Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().
Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Increase the range of various posix message queue limits.
Posix gives the message queue user the ability to 'trade off' the maximum
size of messages with the number of possible messages that can be 'in
flight'. Linux currently makes this trade off more restrictive than it
needs to be.
In particular, the maximum message size today can be made no smaller than
8192. This greatly restricts those applications that would like to have
the ability to post large numbers of very small messages.
So this task lowers the limit that the maximum message size can be set to,
from 8192 to 128. It also lowers the limit that the maximum #number of
messages in flight can be set to, from 10 to 1.
With these changes the message queue user can make better trade offs
between #messages and message size, in order to get everything to fit
within the setrlimit(RLIMIT_MSGQUEUE) limit for that particular user.
This patch also applies the values in
/proc/sys/fs/mqueue/msg_max
/proc/sys/fs/mqueue/msgsize_max
as the defaults for the max #messages allowed and the max message size
allowed, respectively, for those applications that do not supply these.
Previously, the defaults were hardwired to 10 and 8192, respectively.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Joe Korty <joe.korty@ccur.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Shmem segments locked into memory via shmctl(SHM_LOCKED) should not be
kept on the normal LRU, since scanning them is a waste of time and might
throw off kswapd's balancing algorithms. Place them on the unevictable
LRU list instead.
Use the AS_UNEVICTABLE flag to mark address_space of SHM_LOCKed shared
memory regions as unevictable. Then these pages will be culled off the
normal LRU lists during vmscan.
Add new wrapper function to clear the mapping's unevictable state when/if
shared memory segment is munlocked.
Add 'scan_mapping_unevictable_page()' to mm/vmscan.c to scan all pages in
the shmem segment's mapping [struct address_space] for evictability now
that they're no longer locked. If so, move them to the appropriate zone
lru list.
Changes depend on [CONFIG_]UNEVICTABLE_LRU.
[kosaki.motohiro@jp.fujitsu.com: revert shm change]
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Kosaki Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
name and nlen parameters passed to ->strategy hook are unused, remove
them. In general ->strategy hook should know what it's doing, and don't
do something tricky for which, say, pointer to original userspace array
may be needed (name).
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net> [ networking bits ]
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kmem cache passed to constructor is only needed for constructors that are
themselves multiplexeres. Nobody uses this "feature", nor does anybody uses
passed kmem cache in non-trivial way, so pass only pointer to object.
Non-trivial places are:
arch/powerpc/mm/init_64.c
arch/powerpc/mm/hugetlbpage.c
This is flag day, yes.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Jon Tollefson <kniht@linux.vnet.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Matt Mackall <mpm@selenic.com>
[akpm@linux-foundation.org: fix arch/powerpc/mm/hugetlbpage.c]
[akpm@linux-foundation.org: fix mm/slab.c]
[akpm@linux-foundation.org: fix ubifs]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch proposes an alternative to the "magical
positive-versus-negative number trick" Andrew complained about last week
in http://lkml.org/lkml/2008/6/24/418.
This had been introduced with the patches that scale msgmni to the amount
of lowmem. With these patches, msgmni has a registered notification
routine that recomputes msgmni value upon memory add/remove or ipc
namespace creation/ removal.
When msgmni is changed from user space (i.e. value written to the proc
file), that notification routine is unregistered, and the way to make it
registered back is to write a negative value into the proc file. This is
the "magical positive-versus-negative number trick".
To fix this, a new proc file is introduced: /proc/sys/kernel/auto_msgmni.
This file acts as ON/OFF for msgmni automatic recomputing.
With this patch, the process is the following:
1) kernel boots in "automatic recomputing mode"
/proc/sys/kernel/msgmni contains the value that has been computed (depends
on lowmem)
/proc/sys/kernel/automatic_msgmni contains "1"
2) echo <val> > /proc/sys/kernel/msgmni
. sets msg_ctlmni to <val>
. de-activates automatic recomputing (i.e. if, say, some memory is added
msgmni won't be recomputed anymore)
. /proc/sys/kernel/automatic_msgmni now contains "0"
3) echo "0" > /proc/sys/kernel/automatic_msgmni
. de-activates msgmni automatic recomputing
this has the same effect as 2) except that msg_ctlmni's value stays
blocked at its current value)
3) echo "1" > /proc/sys/kernel/automatic_msgmni
. recomputes msgmni's value based on the current available memory size
and number of ipc namespaces
. re-activates automatic recomputing for msgmni.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Solofo Ramangalahy <Solofo.Ramangalahy@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The attached patch:
- reverses the locking order of ulp->lock and sem_lock:
Previously, it was first ulp->lock, then inside sem_lock.
Now it's the other way around.
- converts the undo structure to rcu.
Benefits:
- With the old locking order, IPC_RMID could not kfree the undo structures.
The stale entries remained in the linked lists and were released later.
- The patch fixes a a race in semtimedop(): if both IPC_RMID and a semget() that
recreates exactly the same id happen between find_alloc_undo() and sem_lock,
then semtimedop() would access already kfree'd memory.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Reviewed-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the ipc_lock_down() routines: they used to call idr_find() locklessly
(given that the ipc ids lock was already held), so they are not needed
anymore.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Jim Houston <jim.houston@comcast.net>
Cc: Pierre Peiffer <peifferp@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Call idr_find() locklessly from ipc_lock(), since the idr tree is now RCU
protected.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Jim Houston <jim.houston@comcast.net>
Cc: Pierre Peiffer <peifferp@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The goal of this patchset is to support multiple hugetlb page sizes. This
is achieved by introducing a new struct hstate structure, which
encapsulates the important hugetlb state and constants (eg. huge page
size, number of huge pages currently allocated, etc).
The hstate structure is then passed around the code which requires these
fields, they will do the right thing regardless of the exact hstate they
are operating on.
This patch adds the hstate structure, with a single global instance of it
(default_hstate), and does the basic work of converting hugetlb to use the
hstate.
Future patches will add more hstate structures to allow for different
hugetlbfs mounts to have different page sizes.
[akpm@linux-foundation.org: coding-style fixes]
Acked-by: Adam Litke <agl@us.ibm.com>
Acked-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sysvipc_shm_proc_show() picks between format strings (based on the
expected maximum length of a SHM segment) in a way that prevents gcc from
performing format checks on the seq_printf() parameters. This hid two
format errors - shp->shm_segsz and shp->shm_nattach are both unsigned
long, but were being printed as unsigned int and signed int respectively.
This leads to 32-bit truncation of SHM segment sizes reported in
/proc/sysvipc/shm. (And for nattach, but that's less of a problem for
most users).
This patch makes the format string directly visible to gcc's format
specifier checker, and fixes the two broken format specifiers.
Signed-off-by: Paul Menage <menage@google.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Found a silly double assignment of err is do_shmat. Silly, but good to
clean up the useless code.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When posting:
[PATCH 1/8] Scaling msgmni to the amount of lowmem
(see http://lkml.org/lkml/2008/2/11/171), I have added a KERN_INFO message
that is output each time msgmni is recomputed.
In http://lkml.org/lkml/2008/4/29/575 Tony Luck complained that this
message references an ipc namespace address that is useless.
I first thought of using an audit_log instead of a printk, as suggested by
Serge Hallyn. But unfortunately, we do not have any other information
than the namespace address to provide here too. So I chose to move the
message and output it only at boot time, removing the reference to the
namespace.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Pierre Peiffer <peifferp@gmail.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: "Serge E. Hallyn" <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A very small cleanup for mq_open.
We do not have to call set_close_on_exit if we create the file
descriptor right away with the flag set. We have a function for this
now. The resulting code is smaller and a tiny bit faster.
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use proc_create_data() to make sure that ->proc_fops and ->data be setup
before gluing PDE to main tree.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sys_unshare(CLONE_NEWIPC) doesn't handle the undo lists properly, this can
cause a kernel memory corruption. CLONE_NEWIPC must detach from the existing
undo lists.
Fix, part 1: add support for sys_unshare(CLONE_SYSVSEM)
The original reason to not support it was the potential (inevitable?)
confusion due to the fact that sys_unshare(CLONE_SYSVSEM) has the
inverse meaning of clone(CLONE_SYSVSEM).
Our two most reasonable options then appear to be (1) fully support
CLONE_SYSVSEM, or (2) continue to refuse explicit CLONE_SYSVSEM,
but always do it anyway on unshare(CLONE_SYSVSEM). This patch does
(1).
Changelog:
Apr 16: SEH: switch to Manfred's alternative patch which
removes the unshare_semundo() function which
always refused CLONE_SYSVSEM.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add definitions of USHORT_MAX and others into kernel. ipc uses it and slub
implementation might also use it.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Reviewed-by: Christoph Lameter <clameter@sgi.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: "Pierre Peiffer" <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
semctl_down(), msgctl_down() and shmctl_down() are used to handle the same set
of commands for each kind of IPC. They all start to do the same job (they
retrieve the ipc and do some permission checks) before handling the commands
on their own.
This patch proposes to consolidate this by moving these same pieces of code
into one common function called ipcctl_pre_down().
It simplifies a little these xxxctl_down() functions and increases a little
the maintainability.
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The IPC_SET command performs the same permission setting for all IPCs. This
patch introduces a common ipc_update_perm() function to update these
permissions and makes use of it for all IPCs.
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All IPCs make use of an intermetiate *_setbuf structure to handle the IPC_SET
command. This is not really needed and, moreover, it complicates a little bit
the code.
This patch gets rid of the use of it and uses directly the semid64_ds/
msgid64_ds/shmid64_ds structure.
In addition of removing one struture declaration, it also simplifies and
improves a little bit the common 64-bits path.
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
semctl_down() takes one unused parameter: semnum. This patch proposes to get
rid of it.
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
semctl_down is called with the rwmutex (the one which protects the list of
ipcs) taken in write mode.
This patch moves this rwmutex taken in write-mode inside semctl_down.
This has the advantages of reducing a little bit the window during which this
rwmutex is taken, clarifying sys_semctl, and finally of having a coherent
behaviour with [shm|msg]ctl_down
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, sys_msgctl is not easy to read.
This patch tries to improve that by introducing the msgctl_down function to
handle all commands requiring the rwmutex to be taken in write mode (ie
IPC_SET and IPC_RMID for now). It is the equivalent function of semctl_down
for message queues.
This greatly changes the readability of sys_msgctl and also harmonizes the way
these commands are handled among all IPCs.
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, the way the different commands are handled in sys_shmctl introduces
some duplicated code.
This patch introduces the shmctl_down function to handle all the commands
requiring the rwmutex to be taken in write mode (ie IPC_SET and IPC_RMID for
now). It is the equivalent function of semctl_down for shared memory.
This removes some duplicated code for handling these both commands and
harmonizes the way they are handled among all IPCs.
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Trivial patch which adds some small locking functions and makes use of them to
factorize some part of the code and to make it cleaner.
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The enhancement as asked for by Yasunori: if msgmni is set to a negative
value, register it back into the ipcns notifier chain.
A new interface has been added to the notification mechanism:
notifier_chain_cond_register() registers a notifier block only if not already
registered. With that new interface we avoid taking care of the states
changes in procfs.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: Pierre Peiffer <pierre.peiffer@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make msgmni not recomputed anymore upon ipc namespace creation / removal or
memory add/remove, as soon as it has been set from userland.
As soon as msgmni is explicitly set via procfs or sysctl(), the associated
callback routine is unregistered from the ipc namespace notifier chain.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: Pierre Peiffer <pierre.peiffer@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce a notification mechanism that aims at recomputing msgmni each time
an ipc namespace is created or removed.
The ipc namespace notifier chain already defined for memory hotplug management
is used for that purpose too.
Each time a new ipc namespace is allocated or an existing ipc namespace is
removed, the ipcns notifier chain is notified. The callback routine for each
registered ipc namespace is then activated in order to recompute msgmni for
that namespace.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: Pierre Peiffer <pierre.peiffer@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make the memory hotplug chain's mutex held for a shorter time: when memory is
offlined or onlined a work item is added to the global workqueue. When the
work item is run, it notifies the ipcns notifier chain with the
IPCNS_MEMCHANGED event.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: Pierre Peiffer <pierre.peiffer@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce the registration of a callback routine that recomputes msg_ctlmni
upon memory add / remove.
A single notifier block is registered in the hotplug memory chain for all the
ipc namespaces.
Since the ipc namespaces are not linked together, they have their own
notification chain: one notifier_block is defined per ipc namespace.
Each time an ipc namespace is created (removed) it registers (unregisters) its
notifier block in (from) the ipcns chain. The callback routine registered in
the memory chain invokes the ipcns notifier chain with the IPCNS_LOWMEM event.
Each callback routine registered in the ipcns namespace, in turn, recomputes
msgmni for the owning namespace.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: Pierre Peiffer <pierre.peiffer@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since all the namespaces see the same amount of memory (the total one) this
patch introduces a new variable that counts the ipc namespaces and divides
msg_ctlmni by this counter.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: Pierre Peiffer <pierre.peiffer@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On large systems we'd like to allow a larger number of message queues. In
some cases up to 32K. However simply setting MSGMNI to a larger value may
cause problems for smaller systems.
The first patch of this series introduces a default maximum number of message
queue ids that scales with the amount of lowmem.
Since msgmni is per namespace and there is no amount of memory dedicated to
each namespace so far, the second patch of this series scales msgmni to the
number of ipc namespaces too.
Since msgmni depends on the amount of memory, it becomes necessary to
recompute it upon memory add/remove. In the 4th patch, memory hotplug
management is added: a notifier block is registered into the memory hotplug
notifier chain for the ipc subsystem. Since the ipc namespaces are not linked
together, they have their own notification chain: one notifier_block is
defined per ipc namespace. Each time an ipc namespace is created (removed) it
registers (unregisters) its notifier block in (from) the ipcns chain. The
callback routine registered in the memory chain invokes the ipcns notifier
chain with the IPCNS_MEMCHANGE event. Each callback routine registered in the
ipcns namespace, in turn, recomputes msgmni for the owning namespace.
The 5th patch makes it possible to keep the memory hotplug notifier chain's
lock for a lesser amount of time: instead of directly notifying the ipcns
notifier chain upon memory add/remove, a work item is added to the global
workqueue. When activated, this work item is the one who notifies the ipcns
notifier chain.
Since msgmni depends on the number of ipc namespaces, it becomes necessary to
recompute it upon ipc namespace creation / removal. The 6th patch uses the
ipc namespace notifier chain for that purpose: that chain is notified each
time an ipc namespace is created or removed. This makes it possible to
recompute msgmni for all the namespaces each time one of them is created or
removed.
When msgmni is explicitely set from userspace, we should avoid recomputing it
upon memory add/remove or ipcns creation/removal. This is what the 7th patch
does: it simply unregisters the ipcns callback routine as soon as msgmni has
been changed from procfs or sysctl().
Even if msgmni is set by hand, it should be possible to make it back
automatically recomputed upon memory add/remove or ipcns creation/removal.
This what is achieved in patch 8: if set to a negative value, msgmni is added
back to the ipcns notifier chain, making it automatically recomputed again.
This patch:
Compute msg_ctlmni to make it scale with the amount of lowmem. msg_ctlmni is
now set to make the message queues occupy 1/32 of the available lowmem.
Some cleaning has also been done for the MSGPOOL constant: the msgctl man page
says it's not used, but it also defines it as a size in bytes (the code
expresses it in Kbytes).
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: Pierre Peiffer <pierre.peiffer@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
By continuing to consolidate a little the IPC code, each id can be built
directly in ipc_addid() instead of having it built from each callers of
ipc_addid()
And I also remove shm_addid() in order to have, as much as possible, the
same code for shm/sem/msg.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After further discussion with Christoph Lameter, it has become clear that my
earlier attempts to clean up the mempolicy reference counting were a bit of
overkill in some areas, resulting in superflous ref/unref in what are usually
fast paths. In other areas, further inspection reveals that I botched the
unref for interleave policies.
A separate patch, suitable for upstream/stable trees, fixes up the known
errors in the previous attempt to fix reference counting.
This patch reworks the memory policy referencing counting and, one hopes,
simplifies the code. Maybe I'll get it right this time.
See the update to the numa_memory_policy.txt document for a discussion of
memory policy reference counting that motivates this patch.
Summary:
Lookup of mempolicy, based on (vma, address) need only add a reference for
shared policy, and we need only unref the policy when finished for shared
policies. So, this patch backs out all of the unneeded extra reference
counting added by my previous attempt. It then unrefs only shared policies
when we're finished with them, using the mpol_cond_put() [conditional put]
helper function introduced by this patch.
Note that shmem_swapin() calls read_swap_cache_async() with a dummy vma
containing just the policy. read_swap_cache_async() can call alloc_page_vma()
multiple times, so we can't let alloc_page_vma() unref the shared policy in
this case. To avoid this, we make a copy of any non-null shared policy and
remove the MPOL_F_SHARED flag from the copy. This copy occurs before reading
a page [or multiple pages] from swap, so the overhead should not be an issue
here.
I introduced a new static inline function "mpol_cond_copy()" to copy the
shared policy to an on-stack policy and remove the flags that would require a
conditional free. The current implementation of mpol_cond_copy() assumes that
the struct mempolicy contains no pointers to dynamically allocated structures
that must be duplicated or reference counted during copy.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
get_vma_policy() is not handling fallback to task policy correctly when the
get_policy() vm_op returns NULL. The NULL overwrites the 'pol' variable that
was holding the fallback task mempolicy. So, it was falling back directly to
system default policy.
Fix get_vma_policy() to use only non-NULL policy returned from the vma
get_policy op.
shm_get_policy() was falling back to current task's mempolicy if the "backing
file system" [tmpfs vs hugetlbfs] does not support the get_policy vm_op and
the vma policy is null. This is incorrect for show_numa_maps() which is
likely querying the numa_maps of some task other than current. Remove this
fallback.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the first really tricky patch in the series. It elevates the writer
count on a mount each time a non-special file is opened for write.
We used to do this in may_open(), but Miklos pointed out that __dentry_open()
is used as well to create filps. This will cover even those cases, while a
call in may_open() would not have.
There is also an elevated count around the vfs_create() call in open_namei().
See the comments for more details, but we need this to fix a 'create, remount,
fail r/w open()' race.
Some filesystems forego the use of normal vfs calls to create
struct files. Make sure that these users elevate the mnt
writer count because they will get __fput(), and we need
to make sure they're balanced.
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Arnd Bergmann