[PATCH v2 2/8] qedf: Fix for the deviations from the SAM-4 spec.

Saurav Kashyap
2020-03-30T06:30:47Z

From: Javed Hasan <jhasan@marvell.com>

- Upper limit for retry delay(QEDF_RETRY_DELAY_MAX)
increased from 20 sec to 1 min.
- Log an event/message indicating throttling of I/O
for the target and include scope and retry delay
time returned by the target and the driver enforced delay.
- Synchronizing the update of the fcport->retry_delay_timestamp
between qedf_queuecommand() and qedf_scsi_completion().

Signed-off-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Javed Hasan <jhasan@marvell.com>
---
drivers/scsi/qedf/qedf.h | 2 +-
drivers/scsi/qedf/qedf_io.c | 47 +++++++++++++++++++++++++++++++++++----------
2 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/drivers/scsi/qedf/qedf.h b/drivers/scsi/qedf/qedf.h
index 042ebf6..aaa2ac9 100644
--- a/drivers/scsi/qedf/qedf.h
+++ b/drivers/scsi/qedf/qedf.h
@@ -470,7 +470,7 @@ static inline void qedf_stop_all_io(struct qedf_ctx *qedf)
extern uint qedf_io_tracing;
extern uint qedf_stop_io_on_error;
extern uint qedf_link_down_tmo;
-#define QEDF_RETRY_DELAY_MAX 20 /* 2 seconds */
+#define QEDF_RETRY_DELAY_MAX 600 /* 60 seconds */
extern bool qedf_retry_delay;
extern uint qedf_debug;

diff --git a/drivers/scsi/qedf/qedf_io.c b/drivers/scsi/qedf/qedf_io.c
index e749a2d..f0f455e 100644
--- a/drivers/scsi/qedf/qedf_io.c
+++ b/drivers/scsi/qedf/qedf_io.c
@@ -1021,14 +1021,18 @@ int qedf_post_io_req(struct qedf_rport *fcport, struct qedf_ioreq *io_req)
atomic_inc(&fcport->ios_to_queue);

if (fcport->retry_delay_timestamp) {
+ /* Take fcport->rport_lock for resetting the delay_timestamp */
+ spin_lock_irqsave(&fcport->rport_lock, flags);
if (time_after(jiffies, fcport->retry_delay_timestamp)) {
fcport->retry_delay_timestamp = 0;
} else {
+ spin_unlock_irqrestore(&fcport->rport_lock, flags);
/* If retry_delay timer is active, flow off the ML */
rc = SCSI_MLQUEUE_TARGET_BUSY;
atomic_dec(&fcport->ios_to_queue);
goto exit_qcmd;
}
+ spin_unlock_irqrestore(&fcport->rport_lock, flags);
}

io_req = qedf_alloc_cmd(fcport, QEDF_SCSI_CMD);
@@ -1134,6 +1138,8 @@ void qedf_scsi_completion(struct qedf_ctx *qedf, struct fcoe_cqe *cqe,
int refcount;
u16 scope, qualifier = 0;
u8 fw_residual_flag = 0;
+ unsigned long flags = 0;
+ u16 chk_scope = 0;

if (!io_req)
return;
@@ -1267,16 +1273,8 @@ void qedf_scsi_completion(struct qedf_ctx *qedf, struct fcoe_cqe *cqe,
/* Lower 14 bits */
qualifier = fcp_rsp->retry_delay_timer & 0x3FFF;

- if (qedf_retry_delay &&
- scope > 0 && qualifier > 0 &&
- qualifier <= 0x3FEF) {
- /* Check we don't go over the max */
- if (qualifier > QEDF_RETRY_DELAY_MAX)
- qualifier =
- QEDF_RETRY_DELAY_MAX;
- fcport->retry_delay_timestamp =
- jiffies + (qualifier * HZ / 10);
- }
+ if (qedf_retry_delay)
+ chk_scope = 1;
/* Record stats */
if (io_req->cdb_status ==
SAM_STAT_TASK_SET_FULL)
@@ -1287,6 +1285,35 @@ void qedf_scsi_completion(struct qedf_ctx *qedf, struct fcoe_cqe *cqe,
}
if (io_req->fcp_resid)
scsi_set_resid(sc_cmd, io_req->fcp_resid);
+
+ if (chk_scope == 1)
+ if ((scope == 1 || scope == 2) &&
+ (qualifier > 0 && qualifier <= 0x3FEF)) {
+ /* Check we don't go over the max */
+ if (qualifier > QEDF_RETRY_DELAY_MAX) {
+ qualifier = QEDF_RETRY_DELAY_MAX;
+ QEDF_INFO(&qedf->dbg_ctx, QEDF_LOG_IO,
+ "qualifier = %d\n",
+ (fcp_rsp->retry_delay_timer &
+ 0x3FFF));
+ }
+ QEDF_INFO(&qedf->dbg_ctx, QEDF_LOG_IO,
+ "Scope = %d and qualifier = %d",
+ scope, qualifier);
+ /* Take fcport->rport_lock to
+ * update the retry_delay_timestamp
+ */
+ spin_lock_irqsave(&fcport->rport_lock, flags);
+ fcport->retry_delay_timestamp =
+ jiffies + (qualifier * HZ / 10);
+ spin_unlock_irqrestore(&fcport->rport_lock,
+ flags);
+
+ } else {
+ QEDF_INFO(&qedf->dbg_ctx, QEDF_LOG_IO,
+ "combination of scope = %d and qualifier = %d is not handled in qedf.\n",
+ scope, qualifier);
+ }
break;
default:
QEDF_INFO(&(qedf->dbg_ctx), QEDF_LOG_IO, "fcp_status=%d.\n",
--
1.8.3.1