[PATCH v8 3/5] scsi_transport_fc: Added a new rport state FC_PORTSTATE_MARGINAL

[Muneendra <muneendra.kumar@broadcom.com>]

Added a new rport state FC_PORTSTATE_MARGINAL.

Added a new interface fc_eh_should_retry_cmd which Checks if the cmd
should be retried or not by checking the rport state.
If the rport state is marginal it returns
false to make sure there won't be any retries on the cmd.

Also made changes in fc_remote_port_delete,fc_user_scan_tgt,
fc_timeout_deleted_rport functions  to handle the new rport state
FC_PORTSTATE_MARGINAL.

Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Muneendra <muneendra.kumar@broadcom.com>

---
v8:
Rebased the patches on top of 5.11-rc2

v7:
Removed the changes related to SCMD_NORETRIES_ABORT bit.

Added a new function fc_eh_should_retry_cmd to check whether the cmd
should be retried based on the rport state.

v6:
No change

v5:
Made changes to clear the SCMD_NORETRIES_ABORT bit if the port_state
has changed from marginal to online due to port_delete and port_add
as we need the normal cmd retry behaviour

Made changes in fc_scsi_scan_rport as we are checking FC_PORTSTATE_ONLINE
instead of FC_PORTSTATE_ONLINE and FC_PORTSTATE_MARGINAL

v4:
Made changes in fc_eh_timed_out to call fc_rport_chkmarginal_set_noretries
so that SCMD_NORETRIES_ABORT bit in cmd->state is set if rport state
is marginal.

Removed the newly added scsi_cmd argument to fc_remote_port_chkready
as the current patch handles only SCSI EH timeout/abort case.

v3:
Rearranged the patch so that all the changes with respect to new
rport state is part of this patch.
Added a new argument to scsi_cmd  to fc_remote_port_chkready

v2:
New patch
---
 drivers/scsi/scsi_transport_fc.c | 62 +++++++++++++++++++++++---------
 include/scsi/scsi_transport_fc.h |  4 ++-
 2 files changed, 49 insertions(+), 17 deletions(-)

diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index a926e8f9e56e..ffd25195ae62 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -148,20 +148,23 @@ fc_enum_name_search(host_event_code, fc_host_event_code,
 static struct {
 	enum fc_port_state	value;
 	char			*name;
+	int			matchlen;
 } fc_port_state_names[] = {
-	{ FC_PORTSTATE_UNKNOWN,		"Unknown" },
-	{ FC_PORTSTATE_NOTPRESENT,	"Not Present" },
-	{ FC_PORTSTATE_ONLINE,		"Online" },
-	{ FC_PORTSTATE_OFFLINE,		"Offline" },
-	{ FC_PORTSTATE_BLOCKED,		"Blocked" },
-	{ FC_PORTSTATE_BYPASSED,	"Bypassed" },
-	{ FC_PORTSTATE_DIAGNOSTICS,	"Diagnostics" },
-	{ FC_PORTSTATE_LINKDOWN,	"Linkdown" },
-	{ FC_PORTSTATE_ERROR,		"Error" },
-	{ FC_PORTSTATE_LOOPBACK,	"Loopback" },
-	{ FC_PORTSTATE_DELETED,		"Deleted" },
+	{ FC_PORTSTATE_UNKNOWN,		"Unknown", 7},
+	{ FC_PORTSTATE_NOTPRESENT,	"Not Present", 11 },
+	{ FC_PORTSTATE_ONLINE,		"Online", 6 },
+	{ FC_PORTSTATE_OFFLINE,		"Offline", 7 },
+	{ FC_PORTSTATE_BLOCKED,		"Blocked", 7 },
+	{ FC_PORTSTATE_BYPASSED,	"Bypassed", 8 },
+	{ FC_PORTSTATE_DIAGNOSTICS,	"Diagnostics", 11 },
+	{ FC_PORTSTATE_LINKDOWN,	"Linkdown", 8 },
+	{ FC_PORTSTATE_ERROR,		"Error", 5 },
+	{ FC_PORTSTATE_LOOPBACK,	"Loopback", 8 },
+	{ FC_PORTSTATE_DELETED,		"Deleted", 7 },
+	{ FC_PORTSTATE_MARGINAL,	"Marginal", 8 },
 };
 fc_enum_name_search(port_state, fc_port_state, fc_port_state_names)
+fc_enum_name_match(port_state, fc_port_state, fc_port_state_names)
 #define FC_PORTSTATE_MAX_NAMELEN	20
 
 
@@ -2509,7 +2512,8 @@ fc_user_scan_tgt(struct Scsi_Host *shost, uint channel, uint id, u64 lun)
 		if (rport->scsi_target_id == -1)
 			continue;
 
-		if (rport->port_state != FC_PORTSTATE_ONLINE)
+		if ((rport->port_state != FC_PORTSTATE_ONLINE) &&
+			(rport->port_state != FC_PORTSTATE_MARGINAL))
 			continue;
 
 		if ((channel == rport->channel) &&
@@ -3373,7 +3377,8 @@ fc_remote_port_delete(struct fc_rport  *rport)
 
 	spin_lock_irqsave(shost->host_lock, flags);
 
-	if (rport->port_state != FC_PORTSTATE_ONLINE) {
+	if ((rport->port_state != FC_PORTSTATE_ONLINE) &&
+		(rport->port_state != FC_PORTSTATE_MARGINAL)) {
 		spin_unlock_irqrestore(shost->host_lock, flags);
 		return;
 	}
@@ -3515,7 +3520,8 @@ fc_timeout_deleted_rport(struct work_struct *work)
 	 * target, validate it still is. If not, tear down the
 	 * scsi_target on it.
 	 */
-	if ((rport->port_state == FC_PORTSTATE_ONLINE) &&
+	if (((rport->port_state == FC_PORTSTATE_ONLINE) ||
+		(rport->port_state == FC_PORTSTATE_MARGINAL)) &&
 	    (rport->scsi_target_id != -1) &&
 	    !(rport->roles & FC_PORT_ROLE_FCP_TARGET)) {
 		dev_printk(KERN_ERR, &rport->dev,
@@ -3658,7 +3664,8 @@ fc_scsi_scan_rport(struct work_struct *work)
 	struct fc_internal *i = to_fc_internal(shost->transportt);
 	unsigned long flags;
 
-	if ((rport->port_state == FC_PORTSTATE_ONLINE) &&
+	if (((rport->port_state == FC_PORTSTATE_ONLINE) ||
+		(rport->port_state == FC_PORTSTATE_MARGINAL)) &&
 	    (rport->roles & FC_PORT_ROLE_FCP_TARGET) &&
 	    !(i->f->disable_target_scan)) {
 		scsi_scan_target(&rport->dev, rport->channel,
@@ -3731,6 +3738,28 @@ int fc_block_scsi_eh(struct scsi_cmnd *cmnd)
 }
 EXPORT_SYMBOL(fc_block_scsi_eh);
 
+/*
+ * fc_eh_should_retry_cmd - Checks if the cmd should be retried or not
+ * @scmd:        The SCSI command to be checked
+ *
+ * This checks the rport state to decide if a cmd is
+ * retryable.
+ *
+ * Returns: true if the rport state is not in marginal state.
+ */
+bool fc_eh_should_retry_cmd(struct scsi_cmnd *scmd)
+{
+	struct fc_rport *rport = starget_to_rport(scsi_target(scmd->device));
+
+	if ((rport->port_state != FC_PORTSTATE_ONLINE) &&
+		(scmd->request->cmd_flags & REQ_FAILFAST_TRANSPORT)) {
+		set_host_byte(scmd, DID_TRANSPORT_MARGINAL);
+		return false;
+	}
+	return true;
+}
+EXPORT_SYMBOL_GPL(fc_eh_should_retry_cmd);
+
 /**
  * fc_vport_setup - allocates and creates a FC virtual port.
  * @shost:	scsi host the virtual port is connected to.
@@ -4162,7 +4191,8 @@ static blk_status_t fc_bsg_rport_prep(struct fc_rport *rport)
 	    !(rport->flags & FC_RPORT_FAST_FAIL_TIMEDOUT))
 		return BLK_STS_RESOURCE;
 
-	if (rport->port_state != FC_PORTSTATE_ONLINE)
+	if ((rport->port_state != FC_PORTSTATE_ONLINE) &&
+		(rport->port_state != FC_PORTSTATE_MARGINAL))
 		return BLK_STS_IOERR;
 
 	return BLK_STS_OK;
diff --git a/include/scsi/scsi_transport_fc.h b/include/scsi/scsi_transport_fc.h
index c759b29e46c7..14214ee121ad 100644
--- a/include/scsi/scsi_transport_fc.h
+++ b/include/scsi/scsi_transport_fc.h
@@ -67,6 +67,7 @@ enum fc_port_state {
 	FC_PORTSTATE_ERROR,
 	FC_PORTSTATE_LOOPBACK,
 	FC_PORTSTATE_DELETED,
+	FC_PORTSTATE_MARGINAL,
 };
 
 
@@ -742,7 +743,6 @@ struct fc_function_template {
 	unsigned long	disable_target_scan:1;
 };
 
-
 /**
  * fc_remote_port_chkready - called to validate the remote port state
  *   prior to initiating io to the port.
@@ -758,6 +758,7 @@ fc_remote_port_chkready(struct fc_rport *rport)
 
 	switch (rport->port_state) {
 	case FC_PORTSTATE_ONLINE:
+	case FC_PORTSTATE_MARGINAL:
 		if (rport->roles & FC_PORT_ROLE_FCP_TARGET)
 			result = 0;
 		else if (rport->flags & FC_RPORT_DEVLOSS_PENDING)
@@ -839,6 +840,7 @@ int fc_vport_terminate(struct fc_vport *vport);
 int fc_block_rport(struct fc_rport *rport);
 int fc_block_scsi_eh(struct scsi_cmnd *cmnd);
 enum blk_eh_timer_return fc_eh_timed_out(struct scsi_cmnd *scmd);
+bool fc_eh_should_retry_cmd(struct scsi_cmnd *scmd);
 
 static inline struct Scsi_Host *fc_bsg_to_shost(struct bsg_job *job)
 {
-- 
2.26.2