+ do_io_accounting-use-__for_each_thread.patch added to mm-nonmm-unstable branch

+ do_io_accounting-use-__for_each_thread.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: do_io_accounting: use __for_each_thread()
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     do_io_accounting-use-__for_each_thread.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/do_io_accounting-use-__for_each_thread.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Oleg Nesterov <oleg@redhat.com>
Subject: do_io_accounting: use __for_each_thread()
Date: Mon, 23 Oct 2023 17:33:43 +0200

Rather than while_each_thread() which should be avoided when possible.

This makes the code more clear and allows the next change.

Link: https://lkml.kernel.org/r/20231023153343.GA4629@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/proc/base.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/fs/proc/base.c~do_io_accounting-use-__for_each_thread
+++ a/fs/proc/base.c
@@ -2972,7 +2972,7 @@ static const struct file_operations proc
 #ifdef CONFIG_TASK_IO_ACCOUNTING
 static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
 {
-	struct task_io_accounting acct = task->ioac;
+	struct task_io_accounting acct;
 	unsigned long flags;
 	int result;
 
@@ -2986,14 +2986,18 @@ static int do_io_accounting(struct task_
 	}
 
 	if (whole && lock_task_sighand(task, &flags)) {
-		struct task_struct *t = task;
+		struct signal_struct *sig = task->signal;
+		struct task_struct *t;
 
-		task_io_accounting_add(&acct, &task->signal->ioac);
-		while_each_thread(task, t)
+		acct = sig->ioac;
+		__for_each_thread(sig, t)
 			task_io_accounting_add(&acct, &t->ioac);
 
 		unlock_task_sighand(task, &flags);
+	} else {
+		acct = task->ioac;
 	}
+
 	seq_printf(m,
 		   "rchar: %llu\n"
 		   "wchar: %llu\n"
_

Patches currently in -mm which might be from oleg@redhat.com are

do_io_accounting-use-__for_each_thread.patch
do_io_accounting-use-sig-stats_lock.patch