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bsdacct: turn the acct_lock from on-the-struct to global 

Don't use per-bsd-acct-struct lock, but work with a global one.

This lock is taken for short periods, so it doesn't seem it'll become a
bottleneck, but it will allow us to easily avoid many locking difficulties
in the future.

So this is a mostly s/acct_globals.lock/acct_lock/ over the file.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.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>
This commit is contained in:
Pavel Emelyanov 2008-07-25 01:48:45 -07:00 committed by Linus Torvalds
parent e59a04a7aa
commit a75d979765
1 changed files with 21 additions and 21 deletions
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42
kernel/acct.c
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@ -83,7 +83,6 @@ static void do_acct_process(struct pid_namespace *ns, struct file *);
* the cache line to have the data after getting the lock.
*/
struct bsd_acct_struct {
spinlock_t lock;
volatile int active;
volatile int needcheck;
struct file *file;
@ -91,8 +90,9 @@ struct bsd_acct_struct {
struct timer_list timer;
};
static struct bsd_acct_struct acct_globals __cacheline_aligned =
{__SPIN_LOCK_UNLOCKED(acct_globals.lock)};
static DEFINE_SPINLOCK(acct_lock);
static struct bsd_acct_struct acct_globals __cacheline_aligned;
/*
* Called whenever the timer says to check the free space.
@ -114,11 +114,11 @@ static int check_free_space(struct file *file)
sector_t resume;
sector_t suspend;
spin_lock(&acct_globals.lock);
spin_lock(&acct_lock);
res = acct_globals.active;
if (!file || !acct_globals.needcheck)
goto out;
spin_unlock(&acct_globals.lock);
spin_unlock(&acct_lock);
/* May block */
if (vfs_statfs(file->f_path.dentry, &sbuf))
@ -140,7 +140,7 @@ static int check_free_space(struct file *file)
* If some joker switched acct_globals.file under us we'ld better be
* silent and _not_ touch anything.
*/
spin_lock(&acct_globals.lock);
spin_lock(&acct_lock);
if (file != acct_globals.file) {
if (act)
res = act>0;
@ -165,7 +165,7 @@ static int check_free_space(struct file *file)
add_timer(&acct_globals.timer);
res = acct_globals.active;
out:
spin_unlock(&acct_globals.lock);
spin_unlock(&acct_lock);
return res;
}
@ -173,7 +173,7 @@ out:
* Close the old accounting file (if currently open) and then replace
* it with file (if non-NULL).
*
* NOTE: acct_globals.lock MUST be held on entry and exit.
* NOTE: acct_lock MUST be held on entry and exit.
*/
static void acct_file_reopen(struct file *file)
{
@ -201,11 +201,11 @@ static void acct_file_reopen(struct file *file)
}
if (old_acct) {
mnt_unpin(old_acct->f_path.mnt);
spin_unlock(&acct_globals.lock);
spin_unlock(&acct_lock);
do_acct_process(old_ns, old_acct);
filp_close(old_acct, NULL);
put_pid_ns(old_ns);
spin_lock(&acct_globals.lock);
spin_lock(&acct_lock);
}
}
@ -235,10 +235,10 @@ static int acct_on(char *name)
return error;
}
spin_lock(&acct_globals.lock);
spin_lock(&acct_lock);
mnt_pin(file->f_path.mnt);
acct_file_reopen(file);
spin_unlock(&acct_globals.lock);
spin_unlock(&acct_lock);
mntput(file->f_path.mnt); /* it's pinned, now give up active reference */
@ -272,9 +272,9 @@ asmlinkage long sys_acct(const char __user *name)
} else {
error = security_acct(NULL);
if (!error) {
spin_lock(&acct_globals.lock);
spin_lock(&acct_lock);
acct_file_reopen(NULL);
spin_unlock(&acct_globals.lock);
spin_unlock(&acct_lock);
}
}
return error;
@ -289,10 +289,10 @@ asmlinkage long sys_acct(const char __user *name)
*/
void acct_auto_close_mnt(struct vfsmount *m)
{
spin_lock(&acct_globals.lock);
spin_lock(&acct_lock);
if (acct_globals.file && acct_globals.file->f_path.mnt == m)
acct_file_reopen(NULL);
spin_unlock(&acct_globals.lock);
spin_unlock(&acct_lock);
}
/**
@ -304,12 +304,12 @@ void acct_auto_close_mnt(struct vfsmount *m)
*/
void acct_auto_close(struct super_block *sb)
{
spin_lock(&acct_globals.lock);
spin_lock(&acct_lock);
if (acct_globals.file &&
acct_globals.file->f_path.mnt->mnt_sb == sb) {
acct_file_reopen(NULL);
}
spin_unlock(&acct_globals.lock);
spin_unlock(&acct_lock);
}
/*
@ -594,15 +594,15 @@ void acct_process(void)
if (!acct_globals.file)
return;
spin_lock(&acct_globals.lock);
spin_lock(&acct_lock);
file = acct_globals.file;
if (unlikely(!file)) {
spin_unlock(&acct_globals.lock);
spin_unlock(&acct_lock);
return;
}
get_file(file);
ns = get_pid_ns(acct_globals.ns);
spin_unlock(&acct_globals.lock);
spin_unlock(&acct_lock);
do_acct_process(ns, file);
fput(file);