[PATCH] proc: skip branch in /proc/*/* lookup

From: Alexey Dobriyan
Date: Mon Apr 23 2018 - 17:40:19 EST


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@xxxxxxxxx>
---

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);