From: Alexey Dobriyan <adobriyan@gmail.com>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] proc: skip branch in /proc/*/* lookup
Date: Tue, 24 Apr 2018 00:39:54 +0300 [thread overview]
Message-ID: <20180423213954.GD9043@avx2> (raw)
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.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
fs/proc/base.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2485,14 +2485,11 @@ 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)) {
+ error = proc_pident_instantiate(dir, dentry, task, p);
break;
+ }
}
- if (p >= last)
- goto out;
-
- error = proc_pident_instantiate(dir, dentry, task, p);
-out:
put_task_struct(task);
out_no_task:
return ERR_PTR(error);
reply other threads:[~2018-04-23 21:40 UTC|newest]
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