linux-kernel - [tip:x86/cleanups] x86/process: Avoid unnecessary NULL check in get

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Message-ID: <tip-6e662ae7bce6db602f79e57791f5fb887fb7d371@git.kernel.org>
Date:   Thu, 22 Nov 2018 23:03:57 -0800
From:   tip-bot for Yafang Shao <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     laoar.shao@...il.com, brgerst@...il.com, peterz@...radead.org,
        mingo@...nel.org, dvlasenk@...hat.com,
        linux-kernel@...r.kernel.org, bp@...en8.de,
        torvalds@...ux-foundation.org, luto@...capital.net,
        tglx@...utronix.de, hpa@...or.com
Subject: [tip:x86/cleanups] x86/process: Avoid unnecessary NULL check in
 get_wchan()

Commit-ID:  6e662ae7bce6db602f79e57791f5fb887fb7d371
Gitweb:     https://git.kernel.org/tip/6e662ae7bce6db602f79e57791f5fb887fb7d371
Author:     Yafang Shao <laoar.shao@...il.com>
AuthorDate: Wed, 21 Nov 2018 19:12:14 +0800
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Fri, 23 Nov 2018 07:58:23 +0100

x86/process: Avoid unnecessary NULL check in get_wchan()

Task 'p' is always guaranteed to be non-NULL, because the only call
sites are in fs/proc/ which all guarantee a non-NULL task pointer.

[ mingo: Improved the changelog. ]
Signed-off-by: Yafang Shao <laoar.shao@...il.com>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Denys Vlasenko <dvlasenk@...hat.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/1542798734-12532-1-git-send-email-laoar.shao@gmail.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kernel/process.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index c93fcfdf1673..3c3ee8982577 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -730,7 +730,7 @@ unsigned long get_wchan(struct task_struct *p)
 	unsigned long start, bottom, top, sp, fp, ip, ret = 0;
 	int count = 0;
 
-	if (!p || p == current || p->state == TASK_RUNNING)
+	if (p == current || p->state == TASK_RUNNING)
 		return 0;
 
 	if (!try_get_task_stack(p))