For passthrough we don't retry any error which we get a check condition
for. This results in a lot of callers driving their own retries for all
UAs, specific UAs, NOT_READY, specific sense values or any type of
failure.
This adds the core code to allow passthrough users to specify what errors
they want scsi-ml to retry for them. We can then convert users to drop
a lot of their sense parsing and retry handling.
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
Reviewed-by: John Garry <john.g.garry@xxxxxxxxxx>
---
drivers/scsi/scsi_lib.c | 98 ++++++++++++++++++++++++++++++++++++--
include/scsi/scsi_device.h | 48 +++++++++++++++++++
2 files changed, 143 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index cf3864f72093..868f23517d33 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -184,6 +184,92 @@ void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
__scsi_queue_insert(cmd, reason, true);
}
+void scsi_failures_reset_retries(struct scsi_failures *failures)
+{
+ struct scsi_failure *failure;
+
+ failures->total_retries = 0;
+
+ for (failure = failures->failure_definitions; failure->result;
+ failure++)
+ failure->retries = 0;
+}
+EXPORT_SYMBOL_GPL(scsi_failures_reset_retries);
+
+/**
+ * scsi_check_passthrough - Determine if passthrough scsi_cmnd needs a retry.
+ * @scmd: scsi_cmnd to check.
+ * @failures: scsi_failures struct that lists failures to check for.
+ *
+ * Returns -EAGAIN if the caller should retry else 0.
+ */
+static int scsi_check_passthrough(struct scsi_cmnd *scmd,
+ struct scsi_failures *failures)
+{
+ struct scsi_failure *failure;
+ struct scsi_sense_hdr sshdr;
+ enum sam_status status;
+
+ if (!failures)
+ return 0;
+
+ for (failure = failures->failure_definitions; failure->result;
+ failure++) {
+ if (failure->result == SCMD_FAILURE_RESULT_ANY)
+ goto maybe_retry;
+
+ if (host_byte(scmd->result) &&
+ host_byte(scmd->result) == host_byte(failure->result))
+ goto maybe_retry;
+
+ status = status_byte(scmd->result);
+ if (!status)
+ continue;
+
+ if (failure->result == SCMD_FAILURE_STAT_ANY &&
+ !scsi_status_is_good(scmd->result))
+ goto maybe_retry;
+
+ if (status != status_byte(failure->result))
+ continue;
+
+ if (status_byte(failure->result) != SAM_STAT_CHECK_CONDITION ||
+ failure->sense == SCMD_FAILURE_SENSE_ANY)
+ goto maybe_retry;
+
+ if (!scsi_command_normalize_sense(scmd, &sshdr))
+ return 0;
+
+ if (failure->sense != sshdr.sense_key)
+ continue;
+
+ if (failure->asc == SCMD_FAILURE_ASC_ANY)
+ goto maybe_retry;
+
+ if (failure->asc != sshdr.asc)
+ continue;
+
+ if (failure->ascq == SCMD_FAILURE_ASCQ_ANY ||
+ failure->ascq == sshdr.ascq)
+ goto maybe_retry;
+ }
+
+ return 0;
+
+maybe_retry:
+ if (failure->allowed) {
+ if (failure->allowed == SCMD_FAILURE_NO_LIMIT ||
+ ++failure->retries <= failure->allowed)
+ return -EAGAIN;
+ } else {
+ if (failures->total_allowed == SCMD_FAILURE_NO_LIMIT ||
+ ++failures->total_retries <= failures->total_allowed)
+ return -EAGAIN;
+ }
+
+ return 0;
+}
+
/**
* scsi_execute_cmd - insert request and wait for the result
* @sdev: scsi_device
@@ -192,7 +278,7 @@ void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
* @buffer: data buffer
* @bufflen: len of buffer
* @timeout: request timeout in HZ
- * @retries: number of times to retry request
+ * @ml_retries: number of times scsi-ml will retry request
* @args: Optional args. See struct definition for field descriptions
*
* Returns the scsi_cmnd result field if a command was executed, or a negative
@@ -200,7 +286,7 @@ void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
*/
int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
blk_opf_t opf, void *buffer, unsigned int bufflen,
- int timeout, int retries,
+ int timeout, int ml_retries,
const struct scsi_exec_args *args)
{
static const struct scsi_exec_args default_args;
@@ -214,6 +300,7 @@ int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
args->sense_len != SCSI_SENSE_BUFFERSIZE))
return -EINVAL;
+retry:
req = scsi_alloc_request(sdev->request_queue, opf, args->req_flags);
if (IS_ERR(req))
return PTR_ERR(req);
@@ -227,7 +314,7 @@ int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
scmd = blk_mq_rq_to_pdu(req);
scmd->cmd_len = COMMAND_SIZE(cmd[0]);
memcpy(scmd->cmnd, cmd, scmd->cmd_len);
- scmd->allowed = retries;
+ scmd->allowed = ml_retries;
scmd->flags |= args->scmd_flags;
req->timeout = timeout;
req->rq_flags |= RQF_QUIET;
@@ -237,6 +324,11 @@ int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
*/
blk_execute_rq(req, true);
+ if (scsi_check_passthrough(scmd, args->failures) == -EAGAIN) {
+ blk_mq_free_request(req);
+ goto retry;
+ }
+
/*
* Some devices (USB mass-storage in particular) may transfer
* garbage data together with a residue indicating that the data
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 5ec1e71a09de..4dceabb9dbe1 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -489,6 +489,52 @@ extern int scsi_is_sdev_device(const struct device *);
extern int scsi_is_target_device(const struct device *);
extern void scsi_sanitize_inquiry_string(unsigned char *s, int len);
+/*
+ * scsi_execute_cmd users can set scsi_failure.result to have
+ * scsi_check_passthrough fail/retry a command. scsi_failure.result can be a
+ * specific host byte or message code, or SCMD_FAILURE_RESULT_ANY can be used
+ * to match any host or message code.
+ */
+#define SCMD_FAILURE_RESULT_ANY 0x7fffffff
+/*
+ * Set scsi_failure.result to SCMD_FAILURE_STAT_ANY to fail/retry any failure
+ * scsi_status_is_good returns false for.
+ */
+#define SCMD_FAILURE_STAT_ANY 0xff
+/*
+ * The following can be set to the scsi_failure sense, asc and ascq fields to
+ * match on any sense, ASC, or ASCQ value.
+ */
+#define SCMD_FAILURE_SENSE_ANY 0xff
+#define SCMD_FAILURE_ASC_ANY 0xff
+#define SCMD_FAILURE_ASCQ_ANY 0xff
+/* Always retry a matching failure. */
+#define SCMD_FAILURE_NO_LIMIT -1
+
+struct scsi_failure {
+ int result;
+ u8 sense;
+ u8 asc;
+ u8 ascq;
+ /*
+ * Number of times scsi_execute_cmd will retry the failure. It does
+ * not count for the total_allowed.
+ */
+ s8 allowed;
+ /* Number of times the failure has been retried. */
+ s8 retries;
+};
+
+struct scsi_failures {
+ /*
+ * If a scsi_failure does not have a retry limit setup this limit will
+ * be used.
+ */
+ int total_allowed;
+ int total_retries;
+ struct scsi_failure *failure_definitions;
+};
+
/* Optional arguments to scsi_execute_cmd */
struct scsi_exec_args {
unsigned char *sense; /* sense buffer */
@@ -497,12 +543,14 @@ struct scsi_exec_args {
blk_mq_req_flags_t req_flags; /* BLK_MQ_REQ flags */
int scmd_flags; /* SCMD flags */
int *resid; /* residual length */
+ struct scsi_failures *failures; /* failures to retry */
};
int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
blk_opf_t opf, void *buffer, unsigned int bufflen,
int timeout, int retries,
const struct scsi_exec_args *args);
+void scsi_failures_reset_retries(struct scsi_failures *failures);
extern void sdev_disable_disk_events(struct scsi_device *sdev);
extern void sdev_enable_disk_events(struct scsi_device *sdev);
--
2.34.1
