* [PATCH V2 1/3] block: Allow mapping of vmalloc-ed buffers
2019-06-26 1:47 [PATCH V2 0/3] Fix zone revalidation memory allocation failures Damien Le Moal
@ 2019-06-26 1:47 ` Damien Le Moal
2019-06-26 6:10 ` Christoph Hellwig
2019-06-26 1:47 ` [PATCH V2 2/3] sd_zbc: Fix report zones buffer allocation Damien Le Moal
2019-06-26 1:47 ` [PATCH V2 3/3] block: Limit zone array allocation size Damien Le Moal
2 siblings, 1 reply; 6+ messages in thread
From: Damien Le Moal @ 2019-06-26 1:47 UTC (permalink / raw)
To: linux-scsi, Martin K . Petersen, linux-block, Jens Axboe
Cc: Christoph Hellwig, Bart Van Assche
To allow the SCSI subsystem scsi_execute_req() function to issue
requests using large buffers that are better allocated with vmalloc()
rather than kmalloc(), modify bio_map_kern() to allow passing a buffer
allocated with the vmalloc() function. To do so, simply test the buffer
address using is_vmalloc_addr() and use vmalloc_to_page() instead of
virt_to_page() to obtain the pages of vmalloc-ed buffers.
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
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
block/bio.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/block/bio.c b/block/bio.c
index ce797d73bb43..46e0b970e287 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -16,6 +16,7 @@
#include <linux/workqueue.h>
#include <linux/cgroup.h>
#include <linux/blk-cgroup.h>
+#include <linux/highmem.h>
#include <trace/events/block.h>
#include "blk.h"
@@ -1501,9 +1502,14 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
unsigned long start = kaddr >> PAGE_SHIFT;
const int nr_pages = end - start;
+ bool is_vmalloc = is_vmalloc_addr(data);
+ struct page *page;
int offset, i;
struct bio *bio;
+ if (is_vmalloc)
+ invalidate_kernel_vmap_range(data, len);
+
bio = bio_kmalloc(gfp_mask, nr_pages);
if (!bio)
return ERR_PTR(-ENOMEM);
@@ -1518,7 +1524,11 @@ struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len,
if (bytes > len)
bytes = len;
- if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
+ if (is_vmalloc)
+ page = vmalloc_to_page(data);
+ else
+ page = virt_to_page(data);
+ if (bio_add_pc_page(q, bio, page, bytes,
offset) < bytes) {
/* we don't support partial mappings */
bio_put(bio);
--
2.21.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH V2 2/3] sd_zbc: Fix report zones buffer allocation
2019-06-26 1:47 [PATCH V2 0/3] Fix zone revalidation memory allocation failures Damien Le Moal
2019-06-26 1:47 ` [PATCH V2 1/3] block: Allow mapping of vmalloc-ed buffers Damien Le Moal
@ 2019-06-26 1:47 ` Damien Le Moal
2019-06-26 1:47 ` [PATCH V2 3/3] block: Limit zone array allocation size Damien Le Moal
2 siblings, 0 replies; 6+ messages in thread
From: Damien Le Moal @ 2019-06-26 1:47 UTC (permalink / raw)
To: linux-scsi, Martin K . Petersen, linux-block, Jens Axboe
Cc: Christoph Hellwig, Bart Van Assche
During disk scan and revalidation done with sd_revalidate(), the zones
of a zoned disk are checked using the helper function
blk_revalidate_disk_zones() if a configuration change is detected
(change in the number of zones or zone size). The function
blk_revalidate_disk_zones() issues report_zones calls that are very
large, that is, to obtain zone information for all zones of the disk
with a single command. The size of the report zones command buffer
necessary for such large request generally is lower than the disk
max_hw_sectors and KMALLOC_MAX_SIZE (4MB) and succeeds on boot (no
memory fragmentation), but often fail at run time (e.g. hot-plug
event). This causes the disk revalidation to fail and the disk
capacity to be changed to 0.
This problem can be avoided by using vmalloc() instead of kmalloc() for
the buffer allocation. To limit the amount of memory to be allocated,
this patch also introduces the arbitrary SD_ZBC_REPORT_MAX_ZONES
maximum number of zones to report with a single report zones command.
This limit may be lowered further to satisfy the disk max_hw_sectors
limit. Finally, to ensure that the vmalloc-ed buffer can always be
mapped in a request, the buffer size is further limited to at most
queue_max_segments() pages, allowing successful mapping of the buffer
even in the worst case scenario where none of the buffer pages are
contiguous.
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
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
drivers/scsi/sd_zbc.c | 80 ++++++++++++++++++++++++++++++++-----------
1 file changed, 60 insertions(+), 20 deletions(-)
diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index 7334024b64f1..f1474732784c 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -9,6 +9,7 @@
*/
#include <linux/blkdev.h>
+#include <linux/vmalloc.h>
#include <asm/unaligned.h>
@@ -103,6 +104,48 @@ static int sd_zbc_do_report_zones(struct scsi_disk *sdkp, unsigned char *buf,
return 0;
}
+/*
+ * Maximum number of zones to get with one report zones command.
+ */
+#define SD_ZBC_REPORT_MAX_ZONES 8192U
+
+/**
+ * Allocate a buffer for report zones reply.
+ * @disk: The target disk
+ * @nr_zones: Maximum number of zones to report
+ * @buflen: Size of the buffer allocated
+ * @gfp_mask: Memory allocation mask
+ *
+ */
+static void *sd_zbc_alloc_report_buffer(struct request_queue *q,
+ unsigned int nr_zones, size_t *buflen,
+ gfp_t gfp_mask)
+{
+ size_t bufsize;
+ void *buf;
+
+ /*
+ * Report zone buffer size should be at most 64B times the number of
+ * zones requested plus the 64B reply header, but should be at least
+ * SECTOR_SIZE for ATA devices.
+ * Make sure that this size does not exceed the hardware capabilities.
+ * Furthermore, since the report zone command cannot be split, make
+ * sure that the allocated buffer can always be mapped by limiting the
+ * number of pages allocated to the HBA max segments limit.
+ */
+ nr_zones = min(nr_zones, SD_ZBC_REPORT_MAX_ZONES);
+ bufsize = roundup((nr_zones + 1) * 64, 512);
+ bufsize = min_t(size_t, bufsize,
+ queue_max_hw_sectors(q) << SECTOR_SHIFT);
+ bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
+
+ buf = __vmalloc(bufsize, gfp_mask, PAGE_KERNEL);
+ if (buf)
+ *buflen = bufsize;
+
+ return buf;
+}
+
/**
* sd_zbc_report_zones - Disk report zones operation.
* @disk: The target disk
@@ -118,9 +161,9 @@ int sd_zbc_report_zones(struct gendisk *disk, sector_t sector,
gfp_t gfp_mask)
{
struct scsi_disk *sdkp = scsi_disk(disk);
- unsigned int i, buflen, nrz = *nr_zones;
+ unsigned int i, nrz = *nr_zones;
unsigned char *buf;
- size_t offset = 0;
+ size_t buflen = 0, offset = 0;
int ret = 0;
if (!sd_is_zoned(sdkp))
@@ -132,16 +175,14 @@ int sd_zbc_report_zones(struct gendisk *disk, sector_t sector,
* without exceeding the device maximum command size. For ATA disks,
* buffers must be aligned to 512B.
*/
- buflen = min(queue_max_hw_sectors(disk->queue) << 9,
- roundup((nrz + 1) * 64, 512));
- buf = kmalloc(buflen, gfp_mask);
+ buf = sd_zbc_alloc_report_buffer(disk->queue, nrz, &buflen, gfp_mask);
if (!buf)
return -ENOMEM;
ret = sd_zbc_do_report_zones(sdkp, buf, buflen,
sectors_to_logical(sdkp->device, sector), true);
if (ret)
- goto out_free_buf;
+ goto out;
nrz = min(nrz, get_unaligned_be32(&buf[0]) / 64);
for (i = 0; i < nrz; i++) {
@@ -152,8 +193,8 @@ int sd_zbc_report_zones(struct gendisk *disk, sector_t sector,
*nr_zones = nrz;
-out_free_buf:
- kfree(buf);
+out:
+ kvfree(buf);
return ret;
}
@@ -287,8 +328,6 @@ static int sd_zbc_check_zoned_characteristics(struct scsi_disk *sdkp,
return 0;
}
-#define SD_ZBC_BUF_SIZE 131072U
-
/**
* sd_zbc_check_zones - Check the device capacity and zone sizes
* @sdkp: Target disk
@@ -304,22 +343,23 @@ static int sd_zbc_check_zoned_characteristics(struct scsi_disk *sdkp,
*/
static int sd_zbc_check_zones(struct scsi_disk *sdkp, u32 *zblocks)
{
+ size_t bufsize, buflen;
u64 zone_blocks = 0;
sector_t max_lba, block = 0;
unsigned char *buf;
unsigned char *rec;
- unsigned int buf_len;
- unsigned int list_length;
int ret;
u8 same;
/* Get a buffer */
- buf = kmalloc(SD_ZBC_BUF_SIZE, GFP_KERNEL);
+ buf = sd_zbc_alloc_report_buffer(sdkp->disk->queue,
+ SD_ZBC_REPORT_MAX_ZONES,
+ &bufsize, GFP_NOIO);
if (!buf)
return -ENOMEM;
/* Do a report zone to get max_lba and the same field */
- ret = sd_zbc_do_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE, 0, false);
+ ret = sd_zbc_do_report_zones(sdkp, buf, bufsize, 0, false);
if (ret)
goto out_free;
@@ -355,12 +395,12 @@ static int sd_zbc_check_zones(struct scsi_disk *sdkp, u32 *zblocks)
do {
/* Parse REPORT ZONES header */
- list_length = get_unaligned_be32(&buf[0]) + 64;
+ buflen = min_t(size_t, get_unaligned_be32(&buf[0]) + 64,
+ bufsize);
rec = buf + 64;
- buf_len = min(list_length, SD_ZBC_BUF_SIZE);
/* Parse zone descriptors */
- while (rec < buf + buf_len) {
+ while (rec < buf + buflen) {
u64 this_zone_blocks = get_unaligned_be64(&rec[8]);
if (zone_blocks == 0) {
@@ -376,8 +416,8 @@ static int sd_zbc_check_zones(struct scsi_disk *sdkp, u32 *zblocks)
}
if (block < sdkp->capacity) {
- ret = sd_zbc_do_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE,
- block, true);
+ ret = sd_zbc_do_report_zones(sdkp, buf, bufsize, block,
+ true);
if (ret)
goto out_free;
}
@@ -408,7 +448,7 @@ static int sd_zbc_check_zones(struct scsi_disk *sdkp, u32 *zblocks)
}
out_free:
- kfree(buf);
+ kvfree(buf);
return ret;
}
--
2.21.0
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH V2 3/3] block: Limit zone array allocation size
2019-06-26 1:47 [PATCH V2 0/3] Fix zone revalidation memory allocation failures Damien Le Moal
2019-06-26 1:47 ` [PATCH V2 1/3] block: Allow mapping of vmalloc-ed buffers Damien Le Moal
2019-06-26 1:47 ` [PATCH V2 2/3] sd_zbc: Fix report zones buffer allocation Damien Le Moal
@ 2019-06-26 1:47 ` Damien Le Moal
2 siblings, 0 replies; 6+ messages in thread
From: Damien Le Moal @ 2019-06-26 1:47 UTC (permalink / raw)
To: linux-scsi, Martin K . Petersen, linux-block, Jens Axboe
Cc: Christoph Hellwig, Bart Van Assche
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. Further reduce the likelyhood of these
failures by using kvmalloc() instead of directly allocating contiguous
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
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
---
block/blk-zoned.c | 29 +++++++++++++----------------
include/linux/blkdev.h | 5 +++++
2 files changed, 18 insertions(+), 16 deletions(-)
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index ae7e91bd0618..26f878b9b5f5 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -373,22 +373,20 @@ 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);
+
+ zones = kvcalloc(nrz, sizeof(struct blk_zone), GFP_NOIO);
+ if (!zones) {
+ *nr_zones = 0;
+ return NULL;
}
- return NULL;
+ *nr_zones = nrz;
+
+ return zones;
}
void blk_queue_free_zone_bitmaps(struct request_queue *q)
@@ -443,7 +441,7 @@ 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;
@@ -480,8 +478,7 @@ int blk_revalidate_disk_zones(struct gendisk *disk)
blk_mq_unfreeze_queue(q);
out:
- free_pages((unsigned long)zones,
- get_order(rep_nr_zones * sizeof(struct blk_zone)));
+ kvfree(zones);
kfree(seq_zones_wlock);
kfree(seq_zones_bitmap);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 592669bcc536..f7faac856017 100644
--- 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,
--
2.21.0
^ permalink raw reply related [flat|nested] 6+ messages in thread