The patch titled
Subject: proc: don't use READ_ONCE/WRITE_ONCE for /proc/*/fail-nth
has been added to the -mm tree. Its filename is
proc-dont-use-read_once-write_once-for-proc-fail-nth.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/proc-dont-use-read_once-write_once-for-proc-fail-nth.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/proc-dont-use-read_once-write_once-for-proc-fail-nth.patch
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------------------------------------------------------
From: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Subject: 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.
Link: http://lkml.kernel.org/r/20171120204033.GA9446@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/base.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff -puN fs/proc/base.c~proc-dont-use-read_once-write_once-for-proc-fail-nth fs/proc/base.c
--- a/fs/proc/base.c~proc-dont-use-read_once-write_once-for-proc-fail-nth
+++ a/fs/proc/base.c
@@ -1371,7 +1371,7 @@ static ssize_t proc_fail_nth_write(struc
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
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);
_
Patches currently in -mm which might be from adobriyan@xxxxxxxxx are
proc-use-%u-for-pid-printing-and-slightly-less-stack.patch
proc-dont-use-read_once-write_once-for-proc-fail-nth.patch
proc-fix-proc-map_files-lookup.patch
seq_file-delete-small-value-optimization.patch
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