linux-kernel - [PATCH] proc: don't use READ_ONCE/WRITE

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Message-ID: <20171120204033.GA9446@avx2>
Date:   Mon, 20 Nov 2017 23:40:33 +0300
From:   Alexey Dobriyan <adobriyan@...il.com>
To:     akpm@...ux-foundation.org
Cc:     linux-kernel@...r.kernel.org, akinobu.mita@...il.com
Subject: [PATCH] proc: don't use READ_ONCE/WRITE_ONCE for /proc/*/fail-nth

READ_ONCE and WRITE_ONCE are useless when there is only one read/write
is being made.

Signed-off-by: Alexey Dobriyan <adobriyan@...il.com>
---

 fs/proc/base.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1371,7 +1371,7 @@ static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf,
 	task = get_proc_task(file_inode(file));
 	if (!task)
 		return -ESRCH;
-	WRITE_ONCE(task->fail_nth, n);
+	task->fail_nth = n;
 	put_task_struct(task);
 
 	return count;
@@ -1387,8 +1387,7 @@ static ssize_t proc_fail_nth_read(struct file *file, char __user *buf,
 	task = get_proc_task(file_inode(file));
 	if (!task)
 		return -ESRCH;
-	len = snprintf(numbuf, sizeof(numbuf), "%u\n",
-			READ_ONCE(task->fail_nth));
+	len = snprintf(numbuf, sizeof(numbuf), "%u\n", task->fail_nth);
 	len = simple_read_from_buffer(buf, count, ppos, numbuf, len);
 	put_task_struct(task);