Merge tag 'locking-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:
 "Mutexes:

   - Redo __mutex_init() to reduce generated code size (Sebastian
     Andrzej Siewior)

  Seqlocks:

   - Introduce scoped_seqlock_read() (Peter Zijlstra)

   - Change thread_group_cputime() to use scoped_seqlock_read() (Oleg
     Nesterov)

   - Change do_task_stat() to use scoped_seqlock_read() (Oleg Nesterov)

   - Change do_io_accounting() to use scoped_seqlock_read() (Oleg
     Nesterov)

   - Fix the incorrect documentation of read_seqbegin_or_lock() /
     need_seqretry() (Oleg Nesterov)

   - Allow KASAN to fail optimizing (Peter Zijlstra)

  Local lock updates:

   - Fix all kernel-doc warnings (Randy Dunlap)

   - Add the <linux/local_lock*.h> headers to MAINTAINERS (Sebastian
     Andrzej Siewior)

   - Reduce the risk of shadowing via s/l/__l/ and s/tl/__tl/ (Vincent
     Mailhol)

  Lock debugging:

   - spinlock/debug: Fix data-race in do_raw_write_lock (Alexander
     Sverdlin)

  Atomic primitives infrastructure:

   - atomic: Skip alignment check for try_cmpxchg() old arg (Arnd
     Bergmann)

  Rust runtime integration:

   - sync: atomic: Enable generated Atomic<T> usage (Boqun Feng)

   - sync: atomic: Implement Debug for Atomic<Debug> (Boqun Feng)

   - debugfs: Remove Rust native atomics and replace them with Linux
     versions (Boqun Feng)

   - debugfs: Implement Reader for Mutex<T> only when T is Unpin (Boqun
     Feng)

   - lock: guard: Add T: Unpin bound to DerefMut (Daniel Almeida)

   - lock: Pin the inner data (Daniel Almeida)

   - lock: Add a Pin<&mut T> accessor (Daniel Almeida)"

* tag 'locking-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/local_lock: Fix all kernel-doc warnings
  locking/local_lock: s/l/__l/ and s/tl/__tl/ to reduce the risk of shadowing
  locking/local_lock: Add the <linux/local_lock*.h> headers to MAINTAINERS
  locking/mutex: Redo __mutex_init() to reduce generated code size
  rust: debugfs: Replace the usage of Rust native atomics
  rust: sync: atomic: Implement Debug for Atomic<Debug>
  rust: sync: atomic: Make Atomic*Ops pub(crate)
  seqlock: Allow KASAN to fail optimizing
  rust: debugfs: Implement Reader for Mutex<T> only when T is Unpin
  seqlock: Change do_io_accounting() to use scoped_seqlock_read()
  seqlock: Change do_task_stat() to use scoped_seqlock_read()
  seqlock: Change thread_group_cputime() to use scoped_seqlock_read()
  seqlock: Introduce scoped_seqlock_read()
  documentation: seqlock: fix the wrong documentation of read_seqbegin_or_lock/need_seqretry
  atomic: Skip alignment check for try_cmpxchg() old arg
  rust: lock: Add a Pin<&mut T> accessor
  rust: lock: Pin the inner data
  rust: lock: guard: Add T: Unpin bound to DerefMut
  locking/spinlock/debug: Fix data-race in do_raw_write_lock

2 files changed, 5 insertions, 17 deletions

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 2ae63189091e..cbd4bc4a58e4 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -481,7 +481,6 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 	unsigned long flags;
 	int exit_code = task->exit_code;
 	struct signal_struct *sig = task->signal;
-	unsigned int seq = 1;
 
 	state = *get_task_state(task);
 	vsize = eip = esp = 0;
@@ -538,10 +537,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 	if (permitted && (!whole || num_threads < 2))
 		wchan = !task_is_running(task);
 
-	do {
-		seq++; /* 2 on the 1st/lockless path, otherwise odd */
-		flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);
-
+	scoped_seqlock_read (&sig->stats_lock, ss_lock_irqsave) {
 		cmin_flt = sig->cmin_flt;
 		cmaj_flt = sig->cmaj_flt;
 		cutime = sig->cutime;
@@ -563,8 +559,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 			}
 			rcu_read_unlock();
 		}
-	} while (need_seqretry(&sig->stats_lock, seq));
-	done_seqretry_irqrestore(&sig->stats_lock, seq, flags);
+	}
 
 	if (whole) {
 		thread_group_cputime_adjusted(task, &utime, &stime);
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 6299878e3d97..407b41cb6e7c 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -3043,21 +3043,14 @@ static int do_io_accounting(struct task_struct *task, struct seq_file *m, int wh
 	if (whole) {
 		struct signal_struct *sig = task->signal;
 		struct task_struct *t;
-		unsigned int seq = 1;
-		unsigned long flags;
-
-		rcu_read_lock();
-		do {
-			seq++; /* 2 on the 1st/lockless path, otherwise odd */
-			flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);
 
+		guard(rcu)();
+		scoped_seqlock_read (&sig->stats_lock, ss_lock_irqsave) {
 			acct = sig->ioac;
 			__for_each_thread(sig, t)
 				task_io_accounting_add(&acct, &t->ioac);
 
-		} while (need_seqretry(&sig->stats_lock, seq));
-		done_seqretry_irqrestore(&sig->stats_lock, seq, flags);
-		rcu_read_unlock();
+		}
 	} else {
 		acct = task->ioac;
 	}