do_io_accounting: use __for_each_thread()

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>

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 601329f..7779efd 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2972,7 +2972,7 @@ static const struct file_operations proc_coredump_filter_operations = {
 #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_struct *task, struct seq_file *m, int wh
        }
 
        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"