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 6a2fe5187b6265db0c896aa9e68ec6fb7507a3a4..75cd8d709f7f791e05b31b9a42491da7e918acbc 100644 (file)
--- 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) {