From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932520Ab3KFNXh (ORCPT ); Wed, 6 Nov 2013 08:23:37 -0500 Received: from terminus.zytor.com ([198.137.202.10]:48931 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932208Ab3KFNUO (ORCPT ); Wed, 6 Nov 2013 08:20:14 -0500 Date: Wed, 6 Nov 2013 05:19:42 -0800 From: tip-bot for Oleg Nesterov Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, peterz@infradead.org, oleg@redhat.com, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, peterz@infradead.org, tglx@linutronix.de, oleg@redhat.com In-Reply-To: <20131017182417.GA17753@redhat.com> References: <20131017182417.GA17753@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf: Factor out strncpy() in perf_event_mmap_event() Git-Commit-ID: c7e548b45ce85f765f6262149dd60d9956a31d60 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.1 (terminus.zytor.com [127.0.0.1]); Wed, 06 Nov 2013 05:19:47 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: c7e548b45ce85f765f6262149dd60d9956a31d60 Gitweb: http://git.kernel.org/tip/c7e548b45ce85f765f6262149dd60d9956a31d60 Author: Oleg Nesterov AuthorDate: Thu, 17 Oct 2013 20:24:17 +0200 Committer: Ingo Molnar CommitDate: Wed, 6 Nov 2013 12:34:28 +0100 perf: Factor out strncpy() in perf_event_mmap_event() While this is really minor, but strncpy() does the unnecessary zero-padding till the end of tmp[16] and it is called every time we are going to use the string literal. Turn these strncpy()'s into the single strlcpy() under the new label, saves 72 bytes. Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20131017182417.GA17753@redhat.com Signed-off-by: Ingo Molnar --- kernel/events/core.c | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 17b3c6c..4dc078d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5144,8 +5144,8 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) buf = kmalloc(PATH_MAX, GFP_KERNEL); if (!buf) { - name = strncpy(tmp, "//enomem", sizeof(tmp)); - goto got_name; + name = "//enomem"; + goto cpy_name; } /* * d_path() works from the end of the rb backwards, so we @@ -5154,8 +5154,8 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) */ name = d_path(&file->f_path, buf, PATH_MAX - sizeof(u64)); if (IS_ERR(name)) { - name = strncpy(tmp, "//toolong", sizeof(tmp)); - goto got_name; + name = "//toolong"; + goto cpy_name; } inode = file_inode(vma->vm_file); dev = inode->i_sb->s_dev; @@ -5163,30 +5163,30 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) gen = inode->i_generation; maj = MAJOR(dev); min = MINOR(dev); - + goto got_name; } else { name = (char *)arch_vma_name(vma); - if (name) { - name = strncpy(tmp, name, sizeof(tmp) - 1); - tmp[sizeof(tmp) - 1] = '\0'; - goto got_name; - } + if (name) + goto cpy_name; if (vma->vm_start <= vma->vm_mm->start_brk && vma->vm_end >= vma->vm_mm->brk) { - name = strncpy(tmp, "[heap]", sizeof(tmp)); - goto got_name; + name = "[heap]"; + goto cpy_name; } if (vma->vm_start <= vma->vm_mm->start_stack && vma->vm_end >= vma->vm_mm->start_stack) { - name = strncpy(tmp, "[stack]", sizeof(tmp)); - goto got_name; + name = "[stack]"; + goto cpy_name; } - name = strncpy(tmp, "//anon", sizeof(tmp)); - goto got_name; + name = "//anon"; + goto cpy_name; } +cpy_name: + strlcpy(tmp, name, sizeof(tmp)); + name = tmp; got_name: /* * Since our buffer works in 8 byte units we need to align our string