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Commit 26202928 authored by Damien Le Moal's avatar Damien Le Moal Committed by Jens Axboe
Browse files

block: Limit zone array allocation size 



Limit the size of the struct blk_zone array used in
blk_revalidate_disk_zones() to avoid memory allocation failures leading
to disk revalidation failure. Also further reduce the likelyhood of
such failures by using kvcalloc() (that is vmalloc()) instead of
allocating contiguous pages with alloc_pages().

Fixes: 515ce606 ("scsi: sd_zbc: Fix sd_zbc_report_zones() buffer allocation")
Fixes: e76239a3 ("block: add a report_zones method")
Cc: stable@vger.kernel.org
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b091ac61

block/blk-zoned.c

+20 −16
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ 
#include <linux/rbtree.h>

#include <linux/blkdev.h>

#include <linux/blk-mq.h>

#include <linux/mm.h>

#include <linux/vmalloc.h>

#include <linux/sched/mm.h>



#include "blk.h"
@@ -371,24 +373,27 @@ static inline unsigned long *blk_alloc_zone_bitmap(int node, 
 * Allocate an array of struct blk_zone to get nr_zones zone information.

 * The allocated array may be smaller than nr_zones.

 */

static struct blk_zone *blk_alloc_zones(int node, unsigned int *nr_zones)

static struct blk_zone *blk_alloc_zones(unsigned int *nr_zones)

{

	size_t size = *nr_zones * sizeof(struct blk_zone);

	struct page *page;

	int order;



	for (order = get_order(size); order >= 0; order--) {

		page = alloc_pages_node(node, GFP_NOIO | __GFP_ZERO, order);

		if (page) {

			*nr_zones = min_t(unsigned int, *nr_zones,

				(PAGE_SIZE << order) / sizeof(struct blk_zone));

			return page_address(page);

		}

	}

	struct blk_zone *zones;

	size_t nrz = min(*nr_zones, BLK_ZONED_REPORT_MAX_ZONES);



	/*

	 * GFP_KERNEL here is meaningless as the caller task context has

	 * the PF_MEMALLOC_NOIO flag set in blk_revalidate_disk_zones()

	 * with memalloc_noio_save().

	 */

	zones = kvcalloc(nrz, sizeof(struct blk_zone), GFP_KERNEL);

	if (!zones) {

		*nr_zones = 0;

		return NULL;

	}



	*nr_zones = nrz;



	return zones;

}



void blk_queue_free_zone_bitmaps(struct request_queue *q)

{

	kfree(q->seq_zones_bitmap);
@@ -448,7 +453,7 @@ int blk_revalidate_disk_zones(struct gendisk *disk) 


	/* Get zone information and initialize seq_zones_bitmap */

	rep_nr_zones = nr_zones;

	zones = blk_alloc_zones(q->node, &rep_nr_zones);

	zones = blk_alloc_zones(&rep_nr_zones);

	if (!zones)

		goto out;
@@ -487,8 +492,7 @@ int blk_revalidate_disk_zones(struct gendisk *disk) 
out:

	memalloc_noio_restore(noio_flag);



	free_pages((unsigned long)zones,

		   get_order(rep_nr_zones * sizeof(struct blk_zone)));

	kvfree(zones);

	kfree(seq_zones_wlock);

	kfree(seq_zones_bitmap);

include/linux/blkdev.h

+5 −0
Original line number Diff line number Diff line
@@ -344,6 +344,11 @@ struct queue_limits { 


#ifdef CONFIG_BLK_DEV_ZONED



/*

 * Maximum number of zones to report with a single report zones command.

 */

#define BLK_ZONED_REPORT_MAX_ZONES	8192U



extern unsigned int blkdev_nr_zones(struct block_device *bdev);

extern int blkdev_report_zones(struct block_device *bdev,

			       sector_t sector, struct blk_zone *zones,