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authorAlexey Dobriyan <adobriyan@gmail.com>2008-10-27 22:48:36 +0300
committerAlexey Dobriyan <adobriyan@gmail.com>2009-01-05 12:27:44 +0300
commitb4df2b92d8461444fac429c75ba6e125c63056bc (patch)
tree15149c192776b817eeb6124978f74411490aa1ce /fs/proc/root.c
parentfe0bdec68b77020281dc814805edfe594ae89e0f (diff)
proc: stop using BKL
There are four BKL users in proc: de_put(), proc_lookup_de(), proc_readdir_de(), proc_root_readdir(), 1) de_put() ----------- de_put() is classic atomic_dec_and_test() refcount wrapper -- no BKL needed. BKL doesn't matter to possible refcount leak as well. 2) proc_lookup_de() ------------------- Walking PDE list is protected by proc_subdir_lock(), proc_get_inode() is potentially blocking, all callers of proc_lookup_de() eventually end up from ->lookup hooks which is protected by directory's ->i_mutex -- BKL doesn't protect anything. 3) proc_readdir_de() -------------------- "." and ".." part doesn't need BKL, walking PDE list is under proc_subdir_lock, calling filldir callback is potentially blocking because it writes to luserspace. All proc_readdir_de() callers eventually come from ->readdir hook which is under directory's ->i_mutex -- BKL doesn't protect anything. 4) proc_root_readdir_de() ------------------------- proc_root_readdir_de is ->readdir hook, see (3). Since readdir hooks doesn't use BKL anymore, switch to generic_file_llseek, since it also takes directory's i_mutex. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Diffstat (limited to 'fs/proc/root.c')
-rw-r--r--fs/proc/root.c8
1 files changed, 1 insertions, 7 deletions
diff --git a/fs/proc/root.c b/fs/proc/root.c
index 7761602af9d..f6299a25594 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -16,7 +16,6 @@
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/bitops.h>
-#include <linux/smp_lock.h>
#include <linux/mount.h>
#include <linux/pid_namespace.h>
@@ -162,17 +161,12 @@ static int proc_root_readdir(struct file * filp,
unsigned int nr = filp->f_pos;
int ret;
- lock_kernel();
-
if (nr < FIRST_PROCESS_ENTRY) {
int error = proc_readdir(filp, dirent, filldir);
- if (error <= 0) {
- unlock_kernel();
+ if (error <= 0)
return error;
- }
filp->f_pos = FIRST_PROCESS_ENTRY;
}
- unlock_kernel();
ret = proc_pid_readdir(filp, dirent, filldir);
return ret;