commit 26b95137d673d8d6a9a124d433d968e18298f4ed
author Alexey Dobriyan <adobriyan@gmail.com> Thu Jun 14 15:27:17 2018 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> Fri Jun 15 07:55:24 2018 +0900
tree 1f31d199ff9290dbd082a2559731fb6fce193edc
parent 37a4094e828f3c7673aa9c60f8b2b9d1019db81b

proc: skip branch in /proc/*/* lookup

Code is structured like this:

	for ( ... p < last; p++) {
		if (memcmp == 0)
			break;
	}
	if (p >= last)
		ERROR
	OK

gcc doesn't see that if if lookup succeeds than post loop branch will
never be taken and skip it.

[akpm@linux-foundation.org: proc_pident_instantiate() no longer takes an inode*]
Link: http://lkml.kernel.org/r/20180423213954.GD9043@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/base.c

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 80aa425..b657294 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2439,14 +2439,11 @@ static struct dentry *proc_pident_lookup(struct inode *dir,
 	for (p = ents; p < last; p++) {
 		if (p->len != dentry->d_name.len)
 			continue;
-		if (!memcmp(dentry->d_name.name, p->name, p->len))
+		if (!memcmp(dentry->d_name.name, p->name, p->len)) {
+			res = proc_pident_instantiate(dentry, task, p);
 			break;
+		}
 	}
-	if (p >= last)
-		goto out;
-
-	res = proc_pident_instantiate(dentry, task, p);
-out:
 	put_task_struct(task);
 out_no_task:
 	return res;