From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CE3A23BFAF7; Sat, 17 Oct 2026 17:33:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792258396; cv=none; b=H8SNtf05CHNhnX8WW28oGgq8QdxidcmEZhE8PIJnxD8fbciOUouTjZOCkmrv9OK/Wd6mVQjj1Pa9LN0IpCWnTT8+etHdVNpcnisWprLDQbcbsNxG99+UaziQdnxln1rgr0kFf6ST4kNuviwhKfGaIH8shWd4OCcfW2HAgdqDjSU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792258396; c=relaxed/simple; bh=Pj+j1jPtrE8yHv+dzoEZgcVOdChb+ZyRQkaLocmU/nM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mm/dNUod66Sa8V3tLBc1P3U2a1+LVK3muycBVaxy8Zkpb0P6ayTWTMuzWcpYVGkro2HKn7u+cm12oghUDUwPrj2SDUsncY3MMKRxZ2NA/sUOtRnMiuHjYUtUuRiZ7RwQwYp2K5zm9Fr37257td49cxr8zs38u7hV7lBAGLHn588= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=r1kce0dw; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="r1kce0dw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A73E1F000C6; Sat, 17 Oct 2026 17:33:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792258394; bh=vtxjwtLnnkWA9GYpgOMCes8CauZ5DVXrny0WJe8/ays=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=r1kce0dw7Mnvc45JTZLtzlU3lL/4YB6cAVfNpe86YBIs5jxq+2N+ys/XeT71qoC8O Twh6I4a78M+S/UGFHLQf8eJxeEPz53NbjmI9QCXnjjS4P+QTWYbFAQbmxxRxAuoUrb bKvguagclYBOW5jxYL+SgJ+8iwwbMax6PNsu/sH4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yu Kuai , Song Liu , Sasha Levin Subject: [PATCH 6.6 0843/1674] md: add new helpers to suspend/resume array Date: Sat, 17 Oct 2026 17:51:55 +0200 Message-ID: <20261017160452.766100152@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160431.119607952@linuxfoundation.org> References: <20261017160431.119607952@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yu Kuai [ Upstream commit 714d20150ed85811193ae07a494d91f9927c590f ] Advantages for new apis: - reconfig_mutex is not required; - the weird logical that suspend array hold 'reconfig_mutex' for mddev_check_recovery() to update superblock is not needed; - the specail handling, 'pers->prepare_suspend', for raid456 is not needed; - It's safe to be called at any time once mddev is allocated, and it's designed to be used from slow path where array configuration is changed; - the new helpers is designed to be called before mddev_lock(), hence it support to be interrupted by user as well. Signed-off-by: Yu Kuai Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20231010151958.145896-5-yukuai1@huaweicloud.com Stable-dep-of: 2cc583653bbe ("md: suspend array while updating raid_disks via sysfs") Signed-off-by: Sasha Levin --- drivers/md/md.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++- drivers/md/md.h | 3 ++ 2 files changed, 103 insertions(+), 2 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index 5e13891d85139..f4d9defee5d04 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -443,12 +443,22 @@ void mddev_suspend(struct mddev *mddev) lockdep_is_held(&mddev->reconfig_mutex)); WARN_ON_ONCE(thread && current == thread->tsk); - if (mddev->suspended++) + + /* can't concurrent with __mddev_suspend() and __mddev_resume() */ + mutex_lock(&mddev->suspend_mutex); + if (mddev->suspended++) { + mutex_unlock(&mddev->suspend_mutex); return; + } + wake_up(&mddev->sb_wait); set_bit(MD_ALLOW_SB_UPDATE, &mddev->flags); percpu_ref_kill(&mddev->active_io); + /* + * TODO: cleanup 'pers->prepare_suspend after all callers are replaced + * by __mddev_suspend(). + */ if (mddev->pers && mddev->pers->prepare_suspend) mddev->pers->prepare_suspend(mddev); @@ -458,14 +468,21 @@ void mddev_suspend(struct mddev *mddev) /* restrict memory reclaim I/O during raid array is suspend */ mddev->noio_flag = memalloc_noio_save(); + + mutex_unlock(&mddev->suspend_mutex); } EXPORT_SYMBOL_GPL(mddev_suspend); void mddev_resume(struct mddev *mddev) { lockdep_assert_held(&mddev->reconfig_mutex); - if (--mddev->suspended) + + /* can't concurrent with __mddev_suspend() and __mddev_resume() */ + mutex_lock(&mddev->suspend_mutex); + if (--mddev->suspended) { + mutex_unlock(&mddev->suspend_mutex); return; + } /* entred the memalloc scope from mddev_suspend() */ memalloc_noio_restore(mddev->noio_flag); @@ -476,9 +493,89 @@ void mddev_resume(struct mddev *mddev) set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); md_wakeup_thread(mddev->thread); md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */ + + mutex_unlock(&mddev->suspend_mutex); } EXPORT_SYMBOL_GPL(mddev_resume); +int __mddev_suspend(struct mddev *mddev, bool interruptible) +{ + int err = 0; + + /* + * hold reconfig_mutex to wait for normal io will deadlock, because + * other context can't update super_block, and normal io can rely on + * updating super_block. + */ + lockdep_assert_not_held(&mddev->reconfig_mutex); + + if (interruptible) + err = mutex_lock_interruptible(&mddev->suspend_mutex); + else + mutex_lock(&mddev->suspend_mutex); + if (err) + return err; + + if (mddev->suspended) { + WRITE_ONCE(mddev->suspended, mddev->suspended + 1); + mutex_unlock(&mddev->suspend_mutex); + return 0; + } + + percpu_ref_kill(&mddev->active_io); + if (interruptible) + err = wait_event_interruptible(mddev->sb_wait, + percpu_ref_is_zero(&mddev->active_io)); + else + wait_event(mddev->sb_wait, + percpu_ref_is_zero(&mddev->active_io)); + if (err) { + percpu_ref_resurrect(&mddev->active_io); + mutex_unlock(&mddev->suspend_mutex); + return err; + } + + /* + * For raid456, io might be waiting for reshape to make progress, + * allow new reshape to start while waiting for io to be done to + * prevent deadlock. + */ + WRITE_ONCE(mddev->suspended, mddev->suspended + 1); + + del_timer_sync(&mddev->safemode_timer); + /* restrict memory reclaim I/O during raid array is suspend */ + mddev->noio_flag = memalloc_noio_save(); + + mutex_unlock(&mddev->suspend_mutex); + return 0; +} +EXPORT_SYMBOL_GPL(__mddev_suspend); + +void __mddev_resume(struct mddev *mddev) +{ + lockdep_assert_not_held(&mddev->reconfig_mutex); + + mutex_lock(&mddev->suspend_mutex); + WRITE_ONCE(mddev->suspended, mddev->suspended - 1); + if (mddev->suspended) { + mutex_unlock(&mddev->suspend_mutex); + return; + } + + /* entred the memalloc scope from __mddev_suspend() */ + memalloc_noio_restore(mddev->noio_flag); + + percpu_ref_resurrect(&mddev->active_io); + wake_up(&mddev->sb_wait); + + set_bit(MD_RECOVERY_NEEDED, &mddev->recovery); + md_wakeup_thread(mddev->thread); + md_wakeup_thread(mddev->sync_thread); /* possibly kick off a reshape */ + + mutex_unlock(&mddev->suspend_mutex); +} +EXPORT_SYMBOL_GPL(__mddev_resume); + /* * Generic flush handling for md */ @@ -672,6 +769,7 @@ void mddev_init(struct mddev *mddev) mutex_init(&mddev->open_mutex); mutex_init(&mddev->reconfig_mutex); mutex_init(&mddev->sync_mutex); + mutex_init(&mddev->suspend_mutex); mutex_init(&mddev->bitmap_info.mutex); INIT_LIST_HEAD(&mddev->disks); INIT_LIST_HEAD(&mddev->all_mddevs); diff --git a/drivers/md/md.h b/drivers/md/md.h index 59f92aa48b37e..a487e5c0648b5 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -316,6 +316,7 @@ struct mddev { unsigned long sb_flags; int suspended; + struct mutex suspend_mutex; struct percpu_ref active_io; int ro; int sysfs_active; /* set when sysfs deletes @@ -822,6 +823,8 @@ extern void md_rdev_clear(struct md_rdev *rdev); extern void md_handle_request(struct mddev *mddev, struct bio *bio); extern void mddev_suspend(struct mddev *mddev); extern void mddev_resume(struct mddev *mddev); +extern int __mddev_suspend(struct mddev *mddev, bool interruptible); +extern void __mddev_resume(struct mddev *mddev); extern void md_reload_sb(struct mddev *mddev, int raid_disk); extern void md_update_sb(struct mddev *mddev, int force); -- 2.53.0