scsi: core: Allow passthrough to request midlayer retries

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 the SCSI midlayer 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@oracle.com>
Link: https://lore.kernel.org/r/20240123002220.129141-2-michael.christie@oracle.com
Reviewed-by: John Garry <john.g.garry@oracle.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 48 insertions, 0 deletions

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);