[PATCH] proc: Rewrite the proc dentry flush on exit optimization

To keep the dcache from filling up with dead /proc entries we flush them on
process exit.  However over the years that code has gotten hairy with a
dentry_pointer and a lock in task_struct and misdocumented as a correctness
feature.

I have rewritten this code to look and see if we have a corresponding entry in
the dcache and if so flush it on process exit.  This removes the extra fields
in the task_struct and allows me to trivially handle the case of a
/proc/<tgid>/task/<pid> entry as well as the current /proc/<pid> entries.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 0 insertions, 3 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 8d11d9310db0..122a25c1b997 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -842,8 +842,6 @@ struct task_struct {
         u32 self_exec_id;
 /* Protection of (de-)allocation: mm, files, fs, tty, keyrings */
         spinlock_t alloc_lock;
-/* Protection of proc_dentry: nesting proc_lock, dcache_lock, write_lock_irq(&tasklist_lock); */
-        spinlock_t proc_lock;
 
 #ifdef CONFIG_DEBUG_MUTEXES
         /* mutex deadlock detection */
@@ -856,7 +854,6 @@ struct task_struct {
 /* VM state */
         struct reclaim_state *reclaim_state;
 
-        struct dentry *proc_dentry;
         struct backing_dev_info *backing_dev_info;
 
         struct io_context *io_context;