From: Alexey Dobriyan <adobriyan@sw.ru>
Date: Fri, 8 Feb 2008 12:18:27 +0000 (-0800)
Subject: proc: less LOCK operations during lookup
X-Git-Tag: v2.6.25-rc1~270
X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=4237e0d3de38da640d7c977d68f5f7f1d207a631

proc: less LOCK operations during lookup

Pseudo-code for lookup effectively is:

	LOCK kernel
	LOCK proc_subdir_lock
		find PDE
		UNLOCK proc_subdir_lock

		get inode

		LOCK proc_subdir_lock
		goto unlock
	UNLOCK proc_subdir_lock
	UNLOCK kernel

We can get rid of LOCK/UNLOCK pair after getting inode simply by jumping
to unlock_kernel() directly.

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 6a2fe51..75cd8d7 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -406,12 +406,12 @@ struct dentry *proc_lookup(struct inode * dir, struct dentry *dentry, struct nam
 				spin_unlock(&proc_subdir_lock);
 				error = -EINVAL;
 				inode = proc_get_inode(dir->i_sb, ino, de);
-				spin_lock(&proc_subdir_lock);
-				break;
+				goto out_unlock;
 			}
 		}
 	}
 	spin_unlock(&proc_subdir_lock);
+out_unlock:
 	unlock_kernel();
 
 	if (inode) {