lkml.org 
[lkml]   [2019]   [Jul]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 5.1 61/62] block: Limit zone array allocation size
Date
From: Damien Le Moal <damien.lemoal@wdc.com>

commit 26202928fafad8bda8b478edb7e62c885be623d7 upstream.

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: 515ce6061312 ("scsi: sd_zbc: Fix sd_zbc_report_zones() buffer allocation")
Fixes: e76239a3748c ("block: add a report_zones method")
Cc: stable@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
block/blk-zoned.c | 46 ++++++++++++++++++++++++++++++----------------
include/linux/blkdev.h | 5 +++++
2 files changed, 35 insertions(+), 16 deletions(-)

--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -13,6 +13,9 @@
#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"

@@ -372,22 +375,25 @@ static inline unsigned long *blk_alloc_z
* 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;
}

- return NULL;
+ *nr_zones = nrz;
+
+ return zones;
}

void blk_queue_free_zone_bitmaps(struct request_queue *q)
@@ -414,6 +420,7 @@ int blk_revalidate_disk_zones(struct gen
unsigned long *seq_zones_wlock = NULL, *seq_zones_bitmap = NULL;
unsigned int i, rep_nr_zones = 0, z = 0, nrz;
struct blk_zone *zones = NULL;
+ unsigned int noio_flag;
sector_t sector = 0;
int ret = 0;

@@ -426,6 +433,12 @@ int blk_revalidate_disk_zones(struct gen
return 0;
}

+ /*
+ * Ensure that all memory allocations in this context are done as
+ * if GFP_NOIO was specified.
+ */
+ noio_flag = memalloc_noio_save();
+
if (!blk_queue_is_zoned(q) || !nr_zones) {
nr_zones = 0;
goto update;
@@ -442,7 +455,7 @@ int blk_revalidate_disk_zones(struct gen

/* 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;

@@ -479,8 +492,9 @@ update:
blk_mq_unfreeze_queue(q);

out:
- free_pages((unsigned long)zones,
- get_order(rep_nr_zones * sizeof(struct blk_zone)));
+ memalloc_noio_restore(noio_flag);
+
+ kvfree(zones);
kfree(seq_zones_wlock);
kfree(seq_zones_bitmap);

--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -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,

\
 
 \ /
  Last update: 2019-07-26 17:36    [W:0.130 / U:16.524 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site