For passthrough, we don't retry any error we get a check condition for.
This results in a lot of callers driving their own retries for those types
of errors and retrying all errors, and there has been a request to retry
specific host byte errors.
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
their sense parsing and retry handling.
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
---
drivers/scsi/scsi_error.c | 84 +++++++++++++++++++++++++++++++++++++++
drivers/scsi/scsi_lib.c | 1 +
include/scsi/scsi_cmnd.h | 27 ++++++++++++-
3 files changed, 111 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 36ae7cc5e7d9..2aa162406107 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1832,6 +1832,84 @@ bool scsi_noretry_cmd(struct scsi_cmnd *scmd)
return false;
}
+/**
+ * scsi_check_passthrough - Determine if passthrough scsi_cmnd needs a retry.
+ * @scmd: scsi_cmnd to check.
+ *
+ * Return value:
+ * SCSI_RETURN_NOT_HANDLED - if the caller should process the command
+ * because there is no error or the passthrough user wanted the default
+ * error processing.
+ * SUCCESS, FAILED or NEEDS_RETRY - if this function has determined the
+ * command should be completed, go through the erorr handler due to
+ * missing sense or should be retried.
+ */
+static enum scsi_disposition scsi_check_passthrough(struct scsi_cmnd *scmd)
+{
+ struct scsi_failure *failure;
+ struct scsi_sense_hdr sshdr;
+ enum scsi_disposition ret;
+ enum sam_status status;
+ int i;
+
+ if (!scmd->result || !scmd->failures)
+ return SCSI_RETURN_NOT_HANDLED;
+
+ for (i = 0, failure = &scmd->failures[i]; failure->result;
+ failure = &scmd->failures[++i]) {
+ if (failure->result == SCMD_FAILURE_ANY)
+ goto maybe_retry;
+
+ if (host_byte(scmd->result) &&
+ host_byte(scmd->result) == host_byte(failure->result))
+ goto maybe_retry;
+
+ status = get_status_byte(scmd);
+ if (!status)
+ continue;
+
+ if (failure->result == SCMD_FAILURE_STAT_ANY &&
+ !scsi_status_is_good(scmd->result))
+ goto maybe_retry;
+
+ if (status != __get_status_byte(failure->result))
+ continue;
+
+ if (__get_status_byte(failure->result) !=
+ SAM_STAT_CHECK_CONDITION ||
+ failure->sense == SCMD_FAILURE_SENSE_ANY)
+ goto maybe_retry;
+
+ ret = scsi_start_sense_processing(scmd, &sshdr);
+ if (ret == NEEDS_RETRY)
+ goto maybe_retry;
+ else if (ret != SUCCESS)
+ return ret;
+
+ 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 SCSI_RETURN_NOT_HANDLED;
+
+maybe_retry:
+ if (failure->allowed == SCMD_FAILURE_NO_LIMIT ||
+ ++failure->retries <= failure->allowed)
+ return NEEDS_RETRY;
+
+ return SUCCESS;
+}
+
/**
* scsi_decide_disposition - Disposition a cmd on return from LLD.
* @scmd: SCSI cmd to examine.
@@ -1860,6 +1938,12 @@ enum scsi_disposition scsi_decide_disposition(struct scsi_cmnd *scmd)
return SUCCESS;
}
+ if (blk_rq_is_passthrough(scsi_cmd_to_rq(scmd))) {
+ rtn = scsi_check_passthrough(scmd);
+ if (rtn != SCSI_RETURN_NOT_HANDLED)
+ return rtn;
+ }
+
/*
* first check the host byte, to see if there is anything in there
* that would indicate what we need to do.
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 8b89fab7c420..eae438d53ac5 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1130,6 +1130,7 @@ static void scsi_initialize_rq(struct request *rq)
init_rcu_head(&cmd->rcu);
cmd->jiffies_at_alloc = jiffies;
cmd->retries = 0;
+ cmd->failures = NULL;
}
struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf,
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 7d3622db38ed..c08e083ddab0 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -65,6 +65,24 @@ enum scsi_cmnd_submitter {
SUBMITTED_BY_SCSI_RESET_IOCTL = 2,
} __packed;
+#define SCMD_FAILURE_NONE 0
+#define SCMD_FAILURE_ANY 0x7fffffff
+#define SCMD_FAILURE_STAT_ANY 0xff
+#define SCMD_FAILURE_SENSE_ANY 0xff
+#define SCMD_FAILURE_ASC_ANY 0xff
+#define SCMD_FAILURE_ASCQ_ANY 0xff
+#define SCMD_FAILURE_NO_LIMIT -1
+
+struct scsi_failure {
+ int result;
+ u8 sense;
+ u8 asc;
+ u8 ascq;
+
+ s8 allowed;
+ s8 retries;
+};
+
struct scsi_cmnd {
struct scsi_device *device;
struct list_head eh_entry; /* entry for the host eh_abort_list/eh_cmd_q */
@@ -85,6 +103,8 @@ struct scsi_cmnd {
int retries;
int allowed;
+ /* optional array of failures that passthrough users want retried */
+ struct scsi_failure *failures;
unsigned char prot_op;
unsigned char prot_type;
@@ -330,9 +350,14 @@ static inline void set_status_byte(struct scsi_cmnd *cmd, char status)
cmd->result = (cmd->result & 0xffffff00) | status;
}
+static inline u8 __get_status_byte(int result)
+{
+ return result & 0xff;
+}
+
static inline u8 get_status_byte(struct scsi_cmnd *cmd)
{
- return cmd->result & 0xff;
+ return __get_status_byte(cmd->result);
}
static inline void set_host_byte(struct scsi_cmnd *cmd, char status)
--
2.25.1
