From patchwork Wed Nov 6 23:13:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Damien Le Moal X-Patchwork-Id: 13865617 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E4AC920CCF8 for ; Wed, 6 Nov 2024 23:13:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730934806; cv=none; b=O7P/RdRJXyH/yeKndemhXMQFYu07BFOU2fjXNBbROaC+V1DZPojlnVV2sz2sWfj+1jLz1hJcXDC2gN5xzK3LmRlJ+xIYTQqYMy7mYCCHmXmbIJw4AWRl64lLYnCDQoVKrXc8eDemq7LRvMLJQX3lY8BLDx7WZbv4E3l9tA6jkEM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730934806; c=relaxed/simple; bh=1N5Goib5K31T0qp1Ch2dr3g+MKAz7jdOq9xDH+foR5U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ohlHP8iVpwFxLOnDVEQMXkDCPS9zksJPH5ZTT3OZtKzrQCA6oVlVihjy3lyFr0tfzevshri70N2nTugc0e3HOQQVftYzkjPSiknWxRRIARLW8I7jgA6JPVv9mc2zDzhWRw/cIM/H34nzvzlpxIWVpF6JwzbNFruWvCYnwblZnwI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WLHJBkNX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WLHJBkNX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 572F4C4CED0; Wed, 6 Nov 2024 23:13:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730934805; bh=1N5Goib5K31T0qp1Ch2dr3g+MKAz7jdOq9xDH+foR5U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WLHJBkNXEOOhZSjQewc4IEWZrvQ6XPQO2HrqDbOGF+G5hYC9UHbJ2YS+nQ/GmfhwM H4Exc6GlfPIC7cqUivbBoI9EdXHgu2Unweo6hq8JPyFxvzC/Ua9FVu34S3l515CYG/ Ak1wsMjErVzgQTlyRu9cUj7k+NgnqA6XGxCk1GX5H9jxkCyV+4/zb0MxIRydxsnC1H DGUNBP5QnsJlXHwFochL7KCQ2v21g27THkZuUiQYnPODMQtvmIDjKKdkuLt1LI3hil yYF0+5YTc6HTCk5j/SSCO+WNp1dUICgmtWa0lt2/ZkSmfYdm2OlDZX+q1Nkgieq8T6 HOsyOgTBDAZmw== From: Damien Le Moal To: Jens Axboe , linux-block@vger.kernel.org Cc: Christoph Hellwig Subject: [PATCH 1/2] block: RCU protect disk->conv_zones_bitmap Date: Thu, 7 Nov 2024 08:13:22 +0900 Message-ID: <20241106231323.8008-2-dlemoal@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241106231323.8008-1-dlemoal@kernel.org> References: <20241106231323.8008-1-dlemoal@kernel.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Ensure that a disk revalidation changing the conventional zones bitmap of a disk does not cause invalid memory references when using the disk_zone_is_conv() helper by RCU protecting the disk->conv_zones_bitmap pointer. disk_zone_is_conv() is modified to operate under the RCU read lock and the function disk_set_conv_zones_bitmap() is added to update a disk conv_zones_bitmap pointer using rcu_replace_pointer() with the disk zone_wplugs_lock spinlock held. disk_free_zone_resources() is modified to call disk_update_zone_resources() with a NULL bitmap pointer to free the disk conv_zones_bitmap. disk_set_conv_zones_bitmap() is also used in disk_update_zone_resources() to set the new (revalidated) bitmap and free the old one. Signed-off-by: Damien Le Moal --- block/blk-zoned.c | 43 ++++++++++++++++++++++++++++++------------ include/linux/blkdev.h | 2 +- 2 files changed, 32 insertions(+), 13 deletions(-) diff --git a/block/blk-zoned.c b/block/blk-zoned.c index a287577d1ad6..7a7855555d6d 100644 --- a/block/blk-zoned.c +++ b/block/blk-zoned.c @@ -350,9 +350,14 @@ int blkdev_zone_mgmt_ioctl(struct block_device *bdev, blk_mode_t mode, static inline bool disk_zone_is_conv(struct gendisk *disk, sector_t sector) { - if (!disk->conv_zones_bitmap) - return false; - return test_bit(disk_zone_no(disk, sector), disk->conv_zones_bitmap); + bool is_conv; + + rcu_read_lock(); + is_conv = disk->conv_zones_bitmap && + test_bit(disk_zone_no(disk, sector), disk->conv_zones_bitmap); + rcu_read_unlock(); + + return is_conv; } static bool disk_zone_is_last(struct gendisk *disk, struct blk_zone *zone) @@ -1455,6 +1460,25 @@ static void disk_destroy_zone_wplugs_hash_table(struct gendisk *disk) disk->zone_wplugs_hash_bits = 0; } +static unsigned int disk_set_conv_zones_bitmap(struct gendisk *disk, + unsigned long *bitmap) +{ + unsigned int nr_conv_zones = 0; + unsigned long flags; + + spin_lock_irqsave(&disk->zone_wplugs_lock, flags); + bitmap = rcu_replace_pointer(disk->conv_zones_bitmap, bitmap, + lockdep_is_held(&disk->zone_wplugs_lock)); + if (disk->conv_zones_bitmap) + nr_conv_zones = bitmap_weight(disk->conv_zones_bitmap, + disk->nr_zones); + spin_unlock_irqrestore(&disk->zone_wplugs_lock, flags); + + kfree_rcu_mightsleep(bitmap); + + return nr_conv_zones; +} + void disk_free_zone_resources(struct gendisk *disk) { if (!disk->zone_wplugs_pool) @@ -1478,8 +1502,7 @@ void disk_free_zone_resources(struct gendisk *disk) mempool_destroy(disk->zone_wplugs_pool); disk->zone_wplugs_pool = NULL; - bitmap_free(disk->conv_zones_bitmap); - disk->conv_zones_bitmap = NULL; + disk_set_conv_zones_bitmap(disk, NULL); disk->zone_capacity = 0; disk->last_zone_capacity = 0; disk->nr_zones = 0; @@ -1538,17 +1561,15 @@ static int disk_update_zone_resources(struct gendisk *disk, struct blk_revalidate_zone_args *args) { struct request_queue *q = disk->queue; - unsigned int nr_seq_zones, nr_conv_zones = 0; + unsigned int nr_seq_zones, nr_conv_zones; unsigned int pool_size; struct queue_limits lim; disk->nr_zones = args->nr_zones; disk->zone_capacity = args->zone_capacity; disk->last_zone_capacity = args->last_zone_capacity; - swap(disk->conv_zones_bitmap, args->conv_zones_bitmap); - if (disk->conv_zones_bitmap) - nr_conv_zones = bitmap_weight(disk->conv_zones_bitmap, - disk->nr_zones); + nr_conv_zones = + disk_set_conv_zones_bitmap(disk, args->conv_zones_bitmap); if (nr_conv_zones >= disk->nr_zones) { pr_warn("%s: Invalid number of conventional zones %u / %u\n", disk->disk_name, nr_conv_zones, disk->nr_zones); @@ -1817,8 +1838,6 @@ int blk_revalidate_disk_zones(struct gendisk *disk) disk_free_zone_resources(disk); blk_mq_unfreeze_queue(q); - kfree(args.conv_zones_bitmap); - return ret; } EXPORT_SYMBOL_GPL(blk_revalidate_disk_zones); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 6d1413bd69a5..5687eb2a019c 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -195,7 +195,7 @@ struct gendisk { unsigned int nr_zones; unsigned int zone_capacity; unsigned int last_zone_capacity; - unsigned long *conv_zones_bitmap; + unsigned long __rcu *conv_zones_bitmap; unsigned int zone_wplugs_hash_bits; spinlock_t zone_wplugs_lock; struct mempool_s *zone_wplugs_pool;