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From: Mateusz Guzik <mjguzik@gmail.com>
To: ebiederm@xmission.com, oleg@redhat.com
Cc: brauner@kernel.org, akpm@linux-foundation.org,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Mateusz Guzik <mjguzik@gmail.com>
Subject: [PATCH v3 6/6] pid: drop irq disablement around pidmap_lock
Date: Sat,  1 Feb 2025 17:31:06 +0100	[thread overview]
Message-ID: <20250201163106.28912-7-mjguzik@gmail.com> (raw)
In-Reply-To: <20250201163106.28912-1-mjguzik@gmail.com>

It no longer serves any purpose now that the tasklist_lock ->
pidmap_lock ordering got eliminated.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
---
 kernel/pid.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/kernel/pid.c b/kernel/pid.c
index 73625f28c166..900193de4232 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -115,11 +115,10 @@ static void delayed_put_pid(struct rcu_head *rhp)
 void free_pid(struct pid *pid)
 {
 	int i;
-	unsigned long flags;
 
 	lockdep_assert_not_held(&tasklist_lock);
 
-	spin_lock_irqsave(&pidmap_lock, flags);
+	spin_lock(&pidmap_lock);
 	for (i = 0; i <= pid->level; i++) {
 		struct upid *upid = pid->numbers + i;
 		struct pid_namespace *ns = upid->ns;
@@ -142,7 +141,7 @@ void free_pid(struct pid *pid)
 		idr_remove(&ns->idr, upid->nr);
 	}
 	pidfs_remove_pid(pid);
-	spin_unlock_irqrestore(&pidmap_lock, flags);
+	spin_unlock(&pidmap_lock);
 
 	call_rcu(&pid->rcu, delayed_put_pid);
 }
@@ -210,7 +209,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid,
 		}
 
 		idr_preload(GFP_KERNEL);
-		spin_lock_irq(&pidmap_lock);
+		spin_lock(&pidmap_lock);
 
 		if (tid) {
 			nr = idr_alloc(&tmp->idr, NULL, tid,
@@ -237,7 +236,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid,
 			nr = idr_alloc_cyclic(&tmp->idr, NULL, pid_min,
 					      pid_max, GFP_ATOMIC);
 		}
-		spin_unlock_irq(&pidmap_lock);
+		spin_unlock(&pidmap_lock);
 		idr_preload_end();
 
 		if (nr < 0) {
@@ -271,7 +270,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid,
 
 	upid = pid->numbers + ns->level;
 	idr_preload(GFP_KERNEL);
-	spin_lock_irq(&pidmap_lock);
+	spin_lock(&pidmap_lock);
 	if (!(ns->pid_allocated & PIDNS_ADDING))
 		goto out_unlock;
 	pidfs_add_pid(pid);
@@ -280,18 +279,18 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid,
 		idr_replace(&upid->ns->idr, pid, upid->nr);
 		upid->ns->pid_allocated++;
 	}
-	spin_unlock_irq(&pidmap_lock);
+	spin_unlock(&pidmap_lock);
 	idr_preload_end();
 
 	return pid;
 
 out_unlock:
-	spin_unlock_irq(&pidmap_lock);
+	spin_unlock(&pidmap_lock);
 	idr_preload_end();
 	put_pid_ns(ns);
 
 out_free:
-	spin_lock_irq(&pidmap_lock);
+	spin_lock(&pidmap_lock);
 	while (++i <= ns->level) {
 		upid = pid->numbers + i;
 		idr_remove(&upid->ns->idr, upid->nr);
@@ -301,7 +300,7 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid,
 	if (ns->pid_allocated == PIDNS_ADDING)
 		idr_set_cursor(&ns->idr, 0);
 
-	spin_unlock_irq(&pidmap_lock);
+	spin_unlock(&pidmap_lock);
 
 	kmem_cache_free(ns->pid_cachep, pid);
 	return ERR_PTR(retval);
@@ -309,9 +308,9 @@ struct pid *alloc_pid(struct pid_namespace *ns, pid_t *set_tid,
 
 void disable_pid_allocation(struct pid_namespace *ns)
 {
-	spin_lock_irq(&pidmap_lock);
+	spin_lock(&pidmap_lock);
 	ns->pid_allocated &= ~PIDNS_ADDING;
-	spin_unlock_irq(&pidmap_lock);
+	spin_unlock(&pidmap_lock);
 }
 
 struct pid *find_pid_ns(int nr, struct pid_namespace *ns)
-- 
2.43.0



  parent reply	other threads:[~2025-02-01 16:31 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-01 16:31 [PATCH v3 0/6] reduce tasklist_lock hold time on exit and do some Mateusz Guzik
2025-02-01 16:31 ` [PATCH v3 1/6] exit: perform add_device_randomness() without tasklist_lock Mateusz Guzik
2025-02-03 17:51   ` Oleg Nesterov
2025-02-03 17:55     ` Mateusz Guzik
2025-02-01 16:31 ` [PATCH v3 2/6] exit: hoist get_pid() in release_task() outside of tasklist_lock Mateusz Guzik
2025-02-03 19:27   ` Liam R. Howlett
2025-02-03 19:35     ` Mateusz Guzik
2025-02-03 20:13       ` Liam R. Howlett
2025-02-03 20:22         ` Mateusz Guzik
2025-02-03 20:28           ` Liam R. Howlett
2025-02-04  1:51           ` Andrew Morton
2025-02-01 16:31 ` [PATCH v3 3/6] exit: postpone tty_kref_put() until after tasklist_lock is dropped Mateusz Guzik
2025-02-03 18:06   ` Oleg Nesterov
2025-02-03 19:33     ` Mateusz Guzik
2025-02-04 11:22       ` Oleg Nesterov
2025-02-04 12:12         ` Mateusz Guzik
2025-02-01 16:31 ` [PATCH v3 4/6] pid: sprinkle tasklist_lock asserts Mateusz Guzik
2025-02-01 16:31 ` [PATCH v3 5/6] pid: perform free_pid() calls outside of tasklist_lock Mateusz Guzik
2025-02-03 18:49   ` Oleg Nesterov
2025-02-03 19:31     ` Mateusz Guzik
2025-02-03 20:02       ` Oleg Nesterov
2025-02-01 16:31 ` Mateusz Guzik [this message]
2025-02-01 17:42   ` [PATCH v3 6/6] pid: drop irq disablement around pidmap_lock Oleg Nesterov
2025-02-01 17:45     ` Oleg Nesterov
2025-02-01 18:19   ` David Laight
2025-02-01 18:42     ` Mateusz Guzik
2025-02-01 21:51       ` David Laight
2025-02-01 22:00         ` Matthew Wilcox
2025-02-02 13:55           ` David Laight
2025-02-02 19:34             ` Mateusz Guzik
2025-02-02 20:44               ` David Laight
2025-02-02 22:06                 ` Matthew Wilcox
2025-02-03 17:47 ` [PATCH v3 0/6] reduce tasklist_lock hold time on exit and do some Oleg Nesterov

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