From: Eric W. Biederman <ebiederm@xmission.com>
Date: Mon, 26 Jun 2006 07:25:51 +0000 (-0700)
Subject: [PATCH] proc: Remove tasklist_lock from proc_pid_lookup() and proc_task_lookup()
X-Git-Tag: v2.6.18-rc1~753
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=de7587343bfebc186995ad294e3de0da382eb9bc;p=linux-2.6

[PATCH] proc: Remove tasklist_lock from proc_pid_lookup() and proc_task_lookup()

Since we no longer need the tasklist_lock for get_task_struct the lookup
methods no longer need the tasklist_lock.

This just depends on my previous patch that makes get_task_struct() rcu
safe.

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>
---

diff --git a/fs/proc/base.c b/fs/proc/base.c
index cc578a300a..8180579f87 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1940,11 +1940,11 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct
 	if (tgid == ~0U)
 		goto out;
 
-	read_lock(&tasklist_lock);
+	rcu_read_lock();
 	task = find_task_by_pid(tgid);
 	if (task)
 		get_task_struct(task);
-	read_unlock(&tasklist_lock);
+	rcu_read_unlock();
 	if (!task)
 		goto out;
 
@@ -1988,11 +1988,11 @@ static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry
 	if (tid == ~0U)
 		goto out;
 
-	read_lock(&tasklist_lock);
+	rcu_read_lock();
 	task = find_task_by_pid(tid);
 	if (task)
 		get_task_struct(task);
-	read_unlock(&tasklist_lock);
+	rcu_read_unlock();
 	if (!task)
 		goto out;
 	if (leader->tgid != task->tgid)