[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, 2 insertions, 4 deletions

diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 9dd84884abb1..d4d2081dbaf7 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -99,9 +99,8 @@ extern void proc_misc_init(void);
 
 struct mm_struct;
 
+void proc_flush_task(struct task_struct *task);
 struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *);
-struct dentry *proc_pid_unhash(struct task_struct *p);
-void proc_pid_flush(struct dentry *proc_dentry);
 int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir);
 unsigned long task_vsize(struct mm_struct *);
 int task_statm(struct mm_struct *, int *, int *, int *, int *);
@@ -211,8 +210,7 @@ static inline void proc_net_remove(const char *name)
 #define proc_net_create(name, mode, info)       ({ (void)(mode), NULL; })
 static inline void proc_net_remove(const char *name) {}
 
-static inline struct dentry *proc_pid_unhash(struct task_struct *p) { return NULL; }
-static inline void proc_pid_flush(struct dentry *proc_dentry) { }
+static inline void proc_flush_task(struct task_struct *task) { }
 
 static inline struct proc_dir_entry *create_proc_entry(const char *name,
         mode_t mode, struct proc_dir_entry *parent) { return NULL; }