diff options
author | Damien Le Moal <dlemoal@kernel.org> | 2024-11-07 15:42:59 +0900 |
---|---|---|
committer | Jens Axboe <axboe@kernel.dk> | 2024-11-07 15:30:54 -0700 |
commit | d7cb6d7414ea1b33536fa6d11805cb8dceec1f97 (patch) | |
tree | ebd612c6ac80d9a0cab1c858f3e406c65669a530 /block | |
parent | 8e71afb94d6ed59055b67dadbc423c70104f21a9 (diff) |
block: RCU protect disk->conv_zones_bitmap
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 <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20241107064300.227731-2-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r-- | block/blk-zoned.c | 43 |
1 files changed, 31 insertions, 12 deletions
diff --git a/block/blk-zoned.c b/block/blk-zoned.c index f7e151f665c7..da710067e527 100644 --- a/block/blk-zoned.c +++ b/block/blk-zoned.c @@ -350,9 +350,15 @@ fail: 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); + unsigned long *bitmap; + bool is_conv; + + rcu_read_lock(); + bitmap = rcu_dereference(disk->conv_zones_bitmap); + is_conv = bitmap && test_bit(disk_zone_no(disk, sector), bitmap); + rcu_read_unlock(); + + return is_conv; } static bool disk_zone_is_last(struct gendisk *disk, struct blk_zone *zone) @@ -1455,6 +1461,24 @@ 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); + if (bitmap) + nr_conv_zones = bitmap_weight(bitmap, disk->nr_zones); + bitmap = rcu_replace_pointer(disk->conv_zones_bitmap, bitmap, + lockdep_is_held(&disk->zone_wplugs_lock)); + 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); |