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Date: Sat, 9 Jun 2018 17:29:34 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Bart Van Assche <bart.vanassche@....com>,
Jens Axboe <axboe@...nel.dk>,
Damien Le Moal <damien.lemoal@....com>,
Christoph Hellwig <hch@....de>,
Hannes Reinecke <hare@...e.com>,
"Martin K. Petersen" <martin.petersen@...cle.com>
Subject: [PATCH 4.14 02/41] scsi: sd_zbc: Avoid that resetting a zone fails sporadically
4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Bart Van Assche <bart.vanassche@....com>
commit ccce20fc7968d546fb1e8e147bf5cdc8afc4278a upstream.
Since SCSI scanning occurs asynchronously, since sd_revalidate_disk() is
called from sd_probe_async() and since sd_revalidate_disk() calls
sd_zbc_read_zones() it can happen that sd_zbc_read_zones() is called
concurrently with blkdev_report_zones() and/or blkdev_reset_zones(). That can
cause these functions to fail with -EIO because sd_zbc_read_zones() e.g. sets
q->nr_zones to zero before restoring it to the actual value, even if no drive
characteristics have changed. Avoid that this can happen by making the
following changes:
- Protect the code that updates zone information with blk_queue_enter()
and blk_queue_exit().
- Modify sd_zbc_setup_seq_zones_bitmap() and sd_zbc_setup() such that
these functions do not modify struct scsi_disk before all zone
information has been obtained.
Note: since commit 055f6e18e08f ("block: Make q_usage_counter also track
legacy requests"; kernel v4.15) the request queue freezing mechanism also
affects legacy request queues.
Fixes: 89d947561077 ("sd: Implement support for ZBC devices")
Signed-off-by: Bart Van Assche <bart.vanassche@....com>
Cc: Jens Axboe <axboe@...nel.dk>
Cc: Damien Le Moal <damien.lemoal@....com>
Cc: Christoph Hellwig <hch@....de>
Cc: Hannes Reinecke <hare@...e.com>
Cc: stable@...r.kernel.org # v4.16
Reviewed-by: Damien Le Moal <damien.lemoal@....com>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Damien Le Moal <damien.lemoal@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/scsi/sd_zbc.c | 98 ++++++++++++++++++++++++++++++++------------------
1 file changed, 63 insertions(+), 35 deletions(-)
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -423,7 +423,16 @@ static int sd_zbc_check_capacity(struct
#define SD_ZBC_BUF_SIZE 131072
-static int sd_zbc_check_zone_size(struct scsi_disk *sdkp)
+/**
+ * sd_zbc_check_zone_size - Check the device zone sizes
+ * @sdkp: Target disk
+ *
+ * Check that all zones of the device are equal. The last zone can however
+ * be smaller. The zone size must also be a power of two number of LBAs.
+ *
+ * Returns the zone size in bytes upon success or an error code upon failure.
+ */
+static s64 sd_zbc_check_zone_size(struct scsi_disk *sdkp)
{
u64 zone_blocks = 0;
sector_t block = 0;
@@ -434,8 +443,6 @@ static int sd_zbc_check_zone_size(struct
int ret;
u8 same;
- sdkp->zone_blocks = 0;
-
/* Get a buffer */
buf = kmalloc(SD_ZBC_BUF_SIZE, GFP_KERNEL);
if (!buf)
@@ -470,16 +477,17 @@ static int sd_zbc_check_zone_size(struct
/* Parse zone descriptors */
while (rec < buf + buf_len) {
- zone_blocks = get_unaligned_be64(&rec[8]);
- if (sdkp->zone_blocks == 0) {
- sdkp->zone_blocks = zone_blocks;
- } else if (zone_blocks != sdkp->zone_blocks &&
- (block + zone_blocks < sdkp->capacity
- || zone_blocks > sdkp->zone_blocks)) {
+ u64 this_zone_blocks = get_unaligned_be64(&rec[8]);
+
+ if (zone_blocks == 0) {
+ zone_blocks = this_zone_blocks;
+ } else if (this_zone_blocks != zone_blocks &&
+ (block + this_zone_blocks < sdkp->capacity
+ || this_zone_blocks > zone_blocks)) {
zone_blocks = 0;
goto out;
}
- block += zone_blocks;
+ block += this_zone_blocks;
rec += 64;
}
@@ -492,8 +500,6 @@ static int sd_zbc_check_zone_size(struct
} while (block < sdkp->capacity);
- zone_blocks = sdkp->zone_blocks;
-
out:
if (!zone_blocks) {
if (sdkp->first_scan)
@@ -513,8 +519,7 @@ out:
"Zone size too large\n");
ret = -ENODEV;
} else {
- sdkp->zone_blocks = zone_blocks;
- sdkp->zone_shift = ilog2(zone_blocks);
+ ret = zone_blocks;
}
out_free:
@@ -523,23 +528,44 @@ out_free:
return ret;
}
-static int sd_zbc_setup(struct scsi_disk *sdkp)
+static int sd_zbc_setup(struct scsi_disk *sdkp, u32 zone_blocks)
{
+ struct request_queue *q = sdkp->disk->queue;
+ u32 zone_shift = ilog2(zone_blocks);
+ u32 nr_zones;
/* chunk_sectors indicates the zone size */
- blk_queue_chunk_sectors(sdkp->disk->queue,
- logical_to_sectors(sdkp->device, sdkp->zone_blocks));
- sdkp->zone_shift = ilog2(sdkp->zone_blocks);
- sdkp->nr_zones = sdkp->capacity >> sdkp->zone_shift;
- if (sdkp->capacity & (sdkp->zone_blocks - 1))
- sdkp->nr_zones++;
-
- if (!sdkp->zones_wlock) {
- sdkp->zones_wlock = kcalloc(BITS_TO_LONGS(sdkp->nr_zones),
- sizeof(unsigned long),
- GFP_KERNEL);
- if (!sdkp->zones_wlock)
- return -ENOMEM;
+ blk_queue_chunk_sectors(q,
+ logical_to_sectors(sdkp->device, zone_blocks));
+ nr_zones = round_up(sdkp->capacity, zone_blocks) >> zone_shift;
+
+ /*
+ * Initialize the disk zone write lock bitmap if the number
+ * of zones changed.
+ */
+ if (nr_zones != sdkp->nr_zones) {
+ unsigned long *zones_wlock = NULL;
+
+ if (nr_zones) {
+ zones_wlock = kcalloc(BITS_TO_LONGS(nr_zones),
+ sizeof(unsigned long),
+ GFP_KERNEL);
+ if (!zones_wlock)
+ return -ENOMEM;
+ }
+
+ blk_mq_freeze_queue(q);
+ sdkp->zone_blocks = zone_blocks;
+ sdkp->zone_shift = zone_shift;
+ sdkp->nr_zones = nr_zones;
+ swap(sdkp->zones_wlock, zones_wlock);
+ blk_mq_unfreeze_queue(q);
+
+ kfree(zones_wlock);
+
+ /* READ16/WRITE16 is mandatory for ZBC disks */
+ sdkp->device->use_16_for_rw = 1;
+ sdkp->device->use_10_for_rw = 0;
}
return 0;
@@ -548,6 +574,7 @@ static int sd_zbc_setup(struct scsi_disk
int sd_zbc_read_zones(struct scsi_disk *sdkp,
unsigned char *buf)
{
+ int64_t zone_blocks;
int ret;
if (!sd_is_zoned(sdkp))
@@ -585,19 +612,19 @@ int sd_zbc_read_zones(struct scsi_disk *
* Check zone size: only devices with a constant zone size (except
* an eventual last runt zone) that is a power of 2 are supported.
*/
- ret = sd_zbc_check_zone_size(sdkp);
- if (ret)
+ zone_blocks = sd_zbc_check_zone_size(sdkp);
+ ret = -EFBIG;
+ if (zone_blocks != (u32)zone_blocks)
+ goto err;
+ ret = zone_blocks;
+ if (ret < 0)
goto err;
/* The drive satisfies the kernel restrictions: set it up */
- ret = sd_zbc_setup(sdkp);
+ ret = sd_zbc_setup(sdkp, zone_blocks);
if (ret)
goto err;
- /* READ16/WRITE16 is mandatory for ZBC disks */
- sdkp->device->use_16_for_rw = 1;
- sdkp->device->use_10_for_rw = 0;
-
return 0;
err:
@@ -610,6 +637,7 @@ void sd_zbc_remove(struct scsi_disk *sdk
{
kfree(sdkp->zones_wlock);
sdkp->zones_wlock = NULL;
+ sdkp->nr_zones = 0;
}
void sd_zbc_print_zones(struct scsi_disk *sdkp)
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