qla2xxx: Honor FCP_RSP retry delay timer field.

Parse the retry delay timer field from the FCP response data and if:

- It is not zero
- The SCSI status is busy or queue full

return SCSI_MLQUEUE_TARGET_BUSY for the number of milliseconds specified
in the retry delay timer field.

Signed-off-by: Chad Dupuis <chad.dupuis@qlogic.com>
Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

5 files changed, 32 insertions, 1 deletions

diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index d9daad7db6ce..d529510bbc6c 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -2023,6 +2023,8 @@ typedef struct fc_port {
         unsigned long last_ramp_up;
 
         uint16_t port_id;
+
+        unsigned long retry_delay_timestamp;
 } fc_port_t;
 
 #include "qla_mr.h"
diff --git a/drivers/scsi/qla2xxx/qla_fw.h b/drivers/scsi/qla2xxx/qla_fw.h
index 7f2e1c71cc31..42bb357bf56b 100644
--- a/drivers/scsi/qla2xxx/qla_fw.h
+++ b/drivers/scsi/qla2xxx/qla_fw.h
@@ -567,7 +567,7 @@ struct sts_entry_24xx {
 #define SF_TRANSFERRED_DATA     BIT_11
 #define SF_FCP_RSP_DMA          BIT_0
 
-        uint16_t reserved_2;
+        uint16_t retry_delay;
         uint16_t scsi_status;           /* SCSI status. */
 #define SS_CONFIRMATION_REQ             BIT_12
 
diff --git a/drivers/scsi/qla2xxx/qla_inline.h b/drivers/scsi/qla2xxx/qla_inline.h
index b3b1d6fc2d6c..fee9eb7c8a60 100644
--- a/drivers/scsi/qla2xxx/qla_inline.h
+++ b/drivers/scsi/qla2xxx/qla_inline.h
@@ -279,3 +279,11 @@ qla2x00_handle_mbx_completion(struct qla_hw_data *ha, int status)
                 complete(&ha->mbx_intr_comp);
         }
 }
+
+static inline void
+qla2x00_set_retry_delay_timestamp(fc_port_t *fcport, uint16_t retry_delay)
+{
+        if (retry_delay)
+                fcport->retry_delay_timestamp = jiffies +
+                    (retry_delay * HZ / 10);
+}
diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index 550ffdf0bf17..f15f87e1abd8 100644
--- a/drivers/scsi/qla2xxx/qla_isr.c
+++ b/drivers/scsi/qla2xxx/qla_isr.c
@@ -1983,6 +1983,7 @@ qla2x00_status_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, void *pkt)
         int logit = 1;
         int res = 0;
         uint16_t state_flags = 0;
+        uint16_t retry_delay = 0;
 
         sts = (sts_entry_t *) pkt;
         sts24 = (struct sts_entry_24xx *) pkt;
@@ -2076,6 +2077,9 @@ qla2x00_status_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, void *pkt)
                 host_to_fcp_swap(sts24->data, sizeof(sts24->data));
                 ox_id = le16_to_cpu(sts24->ox_id);
                 par_sense_len = sizeof(sts24->data);
+                /* Valid values of the retry delay timer are 0x1-0xffef */
+                if (sts24->retry_delay > 0 && sts24->retry_delay < 0xfff1)
+                        retry_delay = sts24->retry_delay;
         } else {
                 if (scsi_status & SS_SENSE_LEN_VALID)
                         sense_len = le16_to_cpu(sts->req_sense_length);
@@ -2110,6 +2114,14 @@ qla2x00_status_entry(scsi_qla_host_t *vha, struct rsp_que *rsp, void *pkt)
                 comp_status = CS_DATA_OVERRUN;
 
         /*
+         * Check retry_delay_timer value if we receive a busy or
+         * queue full.
+         */
+        if (lscsi_status == SAM_STAT_TASK_SET_FULL ||
+            lscsi_status == SAM_STAT_BUSY)
+                qla2x00_set_retry_delay_timestamp(fcport, retry_delay);
+
+        /*
          * Based on Host and scsi status generate status code for Linux
          */
         switch (comp_status) {
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index e742890d5d1b..daabf8c9c298 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -731,6 +731,15 @@ qla2xxx_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
                 goto qc24_target_busy;
         }
 
+        /*
+         * Return target busy if we've received a non-zero retry_delay_timer
+         * in a FCP_RSP.
+         */
+        if (time_after(jiffies, fcport->retry_delay_timestamp))
+                fcport->retry_delay_timestamp = 0;
+        else
+                goto qc24_target_busy;
+
         sp = qla2x00_get_sp(vha, fcport, GFP_ATOMIC);
         if (!sp)
                 goto qc24_host_busy;