From: Alexey Dobriyan <adobriyan@gmail.com>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] proc: save decrement during lookup/readdir in /proc/$PID
Date: Tue, 22 Nov 2016 22:51:44 +0300 [thread overview]
Message-ID: <20161122195143.GA29812@avx2> (raw)
Comparison for "<" works equally well as comparison for "<="
but one SUB/LEA is saved (no, it is not optimised away, at least here).
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
fs/proc/base.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2412,14 +2412,14 @@ static struct dentry *proc_pident_lookup(struct inode *dir,
* Yes, it does not scale. And it should not. Don't add
* new entries into /proc/<tgid>/ without very good reasons.
*/
- last = &ents[nents - 1];
- for (p = ents; p <= last; p++) {
+ last = &ents[nents];
+ for (p = ents; p < last; p++) {
if (p->len != dentry->d_name.len)
continue;
if (!memcmp(dentry->d_name.name, p->name, p->len))
break;
}
- if (p > last)
+ if (p >= last)
goto out;
error = proc_pident_instantiate(dir, dentry, task, p);
@@ -2444,7 +2444,7 @@ static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
if (ctx->pos >= nents + 2)
goto out;
- for (p = ents + (ctx->pos - 2); p <= ents + nents - 1; p++) {
+ for (p = ents + (ctx->pos - 2); p < ents + nents; p++) {
if (!proc_fill_cache(file, ctx, p->name, p->len,
proc_pident_instantiate, task, p))
break;
reply other threads:[~2016-11-22 17:51 UTC|newest]
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