4.20-stable review patch. If anyone has any objections, please let me know.
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From: Masato Suzuki masato.suzuki@wdc.com
commit 515ce60613128be7a176a8b82b20c7624f3b440d upstream.
The function sd_zbc_do_report_zones() issues a REPORT ZONES command with a buffer size calculated based on the number of zones requested by the caller. This value should however not exceed the capabilities of the hardware maximum command size, that is, should not exceed the max_hw_sectors limit of the device. This problem leads to failures of report zones commands when re-validating disks with some SAS HBAs.
Fix this by limiting a report zone command buffer size to the minimum of the device max_hw_sectors and calculated value based on the requested number of zones. This does not change the semantic of the report_zones file operation as report zones can always return less zone reports than requested. Short reports are handled using a loop execution of the report_zones file operation in the function blk_report_zones().
[Damien] Before patch 'e76239a3748c ("block: add a report_zones method")', report zones buffer allocation was limited to max_sectors when allocated in blk_report_zones(). This however does not consider the actual format of the device reply which is interface dependent. Limiting the allocation based on the size of the expected reply format rather than the size of the array of generic sturct blkzone passed by blk_report_zones() makes more sense.
Fixes: e76239a3748c ("block: add a report_zones method") Cc: stable@vger.kernel.org Signed-off-by: Masato Suzuki masato.suzuki@wdc.com Signed-off-by: Damien Le Moal damien.lemoal@wdc.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/scsi/sd_zbc.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
--- a/drivers/scsi/sd_zbc.c +++ b/drivers/scsi/sd_zbc.c @@ -142,10 +142,12 @@ int sd_zbc_report_zones(struct gendisk * return -EOPNOTSUPP;
/* - * Get a reply buffer for the number of requested zones plus a header. - * For ATA, buffers must be aligned to 512B. + * Get a reply buffer for the number of requested zones plus a header, + * without exceeding the device maximum command size. For ATA disks, + * buffers must be aligned to 512B. */ - buflen = roundup((nrz + 1) * 64, 512); + buflen = min(queue_max_hw_sectors(disk->queue) << 9, + roundup((nrz + 1) * 64, 512)); buf = kmalloc(buflen, gfp_mask); if (!buf) return -ENOMEM;