Commit 0f11328f authored by Mike Christie's avatar Mike Christie Committed by Martin K. Petersen
Browse files

scsi: sd: Have midlayer retry read_capacity_10() errors 



This has read_capacity_10() have the SCSI midlayer retry errors instead of
driving them itself.

There are 2 behavior changes with this patch:

 1. There is one behavior change where we no longer retry when
    scsi_execute_cmd() returns < 0, but we should be ok. We don't need to
    retry for failures like the queue being removed, and for the case where
    there are no tags/reqs since the block layer waits/retries for us. For
    possible memory allocation failures from blk_rq_map_kern() we use
    GFP_NOIO, so retrying will probably not help.

 2. For the specific UAs we checked for and retried, we would get
    READ_CAPACITY_RETRIES_ON_RESET retries plus whatever retries were left
    from the main loop's retries. Each UA now gets
    READ_CAPACITY_RETRIES_ON_RESET retries, and the other errors get up to
    3 retries. This is most likely ok, because
    READ_CAPACITY_RETRIES_ON_RESET is already 10 and is not based on
    anything specific like a spec or device, so the extra 3 we got from the
    main loop was probably just an accident and is not going to help.

Signed-off-by: default avatarMike Christie <michael.christie@oracle.com>
Link: https://lore.kernel.org/r/20240123002220.129141-16-michael.christie@oracle.com


Acked-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent eea6ef37

drivers/scsi/sd.c

+39 −23
Original line number Diff line number Diff line
@@ -2588,42 +2588,58 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp, 
static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,

						unsigned char *buffer)

{

	unsigned char cmd[16];

	static const u8 cmd[10] = { READ_CAPACITY };

	struct scsi_sense_hdr sshdr;

	struct scsi_failure failure_defs[] = {

		/* Do not retry Medium Not Present */

		{

			.sense = UNIT_ATTENTION,

			.asc = 0x3A,

			.result = SAM_STAT_CHECK_CONDITION,

		},

		{

			.sense = NOT_READY,

			.asc = 0x3A,

			.result = SAM_STAT_CHECK_CONDITION,

		},

		 /* Device reset might occur several times so retry a lot */

		{

			.sense = UNIT_ATTENTION,

			.asc = 0x29,

			.allowed = READ_CAPACITY_RETRIES_ON_RESET,

			.result = SAM_STAT_CHECK_CONDITION,

		},

		/* Any other error not listed above retry 3 times */

		{

			.result = SCMD_FAILURE_RESULT_ANY,

			.allowed = 3,

		},

		{}

	};

	struct scsi_failures failures = {

		.failure_definitions = failure_defs,

	};

	const struct scsi_exec_args exec_args = {

		.sshdr = &sshdr,

		.failures = &failures,

	};

	int sense_valid = 0;

	int the_result;

	int retries = 3, reset_retries = READ_CAPACITY_RETRIES_ON_RESET;

	sector_t lba;

	unsigned sector_size;



	do {

		cmd[0] = READ_CAPACITY;

		memset(&cmd[1], 0, 9);

	memset(buffer, 0, 8);



	the_result = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN, buffer,

				      8, SD_TIMEOUT, sdkp->max_retries,

				      &exec_args);



		if (media_not_present(sdkp, &sshdr))

			return -ENODEV;



	if (the_result > 0) {

		sense_valid = scsi_sense_valid(&sshdr);

			if (sense_valid &&

			    sshdr.sense_key == UNIT_ATTENTION &&

			    sshdr.asc == 0x29 && sshdr.ascq == 0x00)

				/* Device reset might occur several times,

				 * give it one more chance */

				if (--reset_retries > 0)

					continue;

		}

		retries--;



	} while (the_result && retries);

		if (media_not_present(sdkp, &sshdr))

			return -ENODEV;

	}



	if (the_result) {

		sd_print_result(sdkp, "Read Capacity(10) failed", the_result);