From 93eab050d33c71412bf70e81ac47d304ad906812 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 3 Dec 2019 10:39:08 +0100 Subject: [PATCH] block: set the zone size in blk_revalidate_disk_zones atomically MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The current zone revalidation code has a major problem in that it doesn't update the zone size and q->nr_zones atomically, leading to a short window where an out of bounds access to the zone arrays is possible. To fix this move the setting of the zone size into the crticial sections blk_revalidate_disk_zones so that it gets updated together with the zone bitmaps and q->nr_zones. This also slightly simplifies the caller as it deducts the zone size from the report_zones. This change also allows to check for a power of two zone size in generic code. Reported-by: Hans Holmberg Reviewed-by: Javier González Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/blk-zoned.c | 59 ++++++++++++++++++++--------------- drivers/block/null_blk_main.c | 3 +- drivers/scsi/sd_zbc.c | 2 -- 3 files changed, 35 insertions(+), 29 deletions(-) diff --git a/block/blk-zoned.c b/block/blk-zoned.c index 51d427659ce7..d00fcfd71dfe 100644 --- a/block/blk-zoned.c +++ b/block/blk-zoned.c @@ -343,6 +343,7 @@ struct blk_revalidate_zone_args { unsigned long *conv_zones_bitmap; unsigned long *seq_zones_wlock; unsigned int nr_zones; + sector_t zone_sectors; sector_t sector; }; @@ -355,25 +356,33 @@ static int blk_revalidate_zone_cb(struct blk_zone *zone, unsigned int idx, struct blk_revalidate_zone_args *args = data; struct gendisk *disk = args->disk; struct request_queue *q = disk->queue; - sector_t zone_sectors = blk_queue_zone_sectors(q); sector_t capacity = get_capacity(disk); /* * All zones must have the same size, with the exception on an eventual * smaller last zone. */ - if (zone->start + zone_sectors < capacity && - zone->len != zone_sectors) { - pr_warn("%s: Invalid zoned device with non constant zone size\n", - disk->disk_name); - return false; - } + if (zone->start == 0) { + if (zone->len == 0 || !is_power_of_2(zone->len)) { + pr_warn("%s: Invalid zoned device with non power of two zone size (%llu)\n", + disk->disk_name, zone->len); + return -ENODEV; + } - if (zone->start + zone->len >= capacity && - zone->len > zone_sectors) { - pr_warn("%s: Invalid zoned device with larger last zone size\n", - disk->disk_name); - return -ENODEV; + args->zone_sectors = zone->len; + args->nr_zones = (capacity + zone->len - 1) >> ilog2(zone->len); + } else if (zone->start + args->zone_sectors < capacity) { + if (zone->len != args->zone_sectors) { + pr_warn("%s: Invalid zoned device with non constant zone size\n", + disk->disk_name); + return -ENODEV; + } + } else { + if (zone->len > args->zone_sectors) { + pr_warn("%s: Invalid zoned device with larger last zone size\n", + disk->disk_name); + return -ENODEV; + } } /* Check for holes in the zone report */ @@ -428,9 +437,9 @@ int blk_revalidate_disk_zones(struct gendisk *disk) struct request_queue *q = disk->queue; struct blk_revalidate_zone_args args = { .disk = disk, - .nr_zones = blkdev_nr_zones(disk), }; - int ret = 0; + unsigned int noio_flag; + int ret; if (WARN_ON_ONCE(!blk_queue_is_zoned(q))) return -EIO; @@ -438,24 +447,22 @@ int blk_revalidate_disk_zones(struct gendisk *disk) return -EIO; /* - * Ensure that all memory allocations in this context are done as - * if GFP_NOIO was specified. + * Ensure that all memory allocations in this context are done as if + * GFP_NOIO was specified. */ - if (args.nr_zones) { - unsigned int noio_flag = memalloc_noio_save(); - - ret = disk->fops->report_zones(disk, 0, args.nr_zones, - blk_revalidate_zone_cb, &args); - memalloc_noio_restore(noio_flag); - } + noio_flag = memalloc_noio_save(); + ret = disk->fops->report_zones(disk, 0, UINT_MAX, + blk_revalidate_zone_cb, &args); + memalloc_noio_restore(noio_flag); /* - * Install the new bitmaps, making sure the queue is stopped and - * all I/Os are completed (i.e. a scheduler is not referencing the - * bitmaps). + * Install the new bitmaps and update nr_zones only once the queue is + * stopped and all I/Os are completed (i.e. a scheduler is not + * referencing the bitmaps). */ blk_mq_freeze_queue(q); if (ret >= 0) { + blk_queue_chunk_sectors(q, args.zone_sectors); q->nr_zones = args.nr_zones; swap(q->seq_zones_wlock, args.seq_zones_wlock); swap(q->conv_zones_bitmap, args.conv_zones_bitmap); diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c index 860fb2560cdf..ce1a05e41e88 100644 --- a/drivers/block/null_blk_main.c +++ b/drivers/block/null_blk_main.c @@ -1557,6 +1557,8 @@ static int null_gendisk_register(struct nullb *nullb) if (ret) return ret; } else { + blk_queue_chunk_sectors(nullb->q, + nullb->dev->zone_size_sects); nullb->q->nr_zones = blkdev_nr_zones(disk); } } @@ -1720,7 +1722,6 @@ static int null_add_dev(struct nullb_device *dev) if (rv) goto out_cleanup_blk_queue; - blk_queue_chunk_sectors(nullb->q, dev->zone_size_sects); nullb->q->limits.zoned = BLK_ZONED_HM; blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, nullb->q); blk_queue_required_elevator_features(nullb->q, diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c index f47d3874094e..e0bd4cf17230 100644 --- a/drivers/scsi/sd_zbc.c +++ b/drivers/scsi/sd_zbc.c @@ -414,8 +414,6 @@ int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf) goto err; /* The drive satisfies the kernel restrictions: set it up */ - blk_queue_chunk_sectors(sdkp->disk->queue, - logical_to_sectors(sdkp->device, zone_blocks)); blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, sdkp->disk->queue); blk_queue_required_elevator_features(sdkp->disk->queue, ELEVATOR_F_ZBD_SEQ_WRITE);