lpfc: Remove host_lock unlock() + lock() from lpfc_queuecommand()

From: Nicholas Bellinger<[email protected]>

This patch removes the now legacy host_lock unlock() + lock() optimization from lpfc_scsi.c:lpfc_queuecommand(). This also includes setting the SHT->unlocked_qcmd=1 for host_lock less lpfc lpfc_queuecommand() operation.

Signed-off-by Nicholas A. Bellinger<[email protected]>

---
  drivers/scsi/lpfc/lpfc_scsi.c |    4 ++--
  1 files changed, 2 insertions(+), 2 deletions(-)

drivers/scsi/lpfc/lpfc_scsi.c +1 -2

index 2e51aa6..69fe31e 100644
@@ -3023,11 +3023,9 @@ lpfc_queuecommand(struct scsi_cmnd *cmnd, void (*done) (struct scsi_cmnd *))
  		goto out_host_busy_free_buf;
  	}
  	if (phba->cfg_poll&  ENABLE_FCP_RING_POLLING) {
-		spin_unlock(shost->host_lock);
  		lpfc_sli_handle_fast_ring_event(phba,
  			&phba->sli.ring[LPFC_FCP_RING], HA_R0RE_REQ);
 
-		spin_lock(shost->host_lock);
  		if (phba->cfg_poll&  DISABLE_FCP_RING_INT)
  			lpfc_poll_rearm_timer(phba);
  	}

@@ -3723,6 +3721,7 @@ struct scsi_host_template lpfc_template = {
  	.slave_destroy		= lpfc_slave_destroy,
  	.scan_finished		= lpfc_scan_finished,
  	.this_id		= -1,
+	.unlocked_qcmd		= 1,
  	.sg_tablesize		= LPFC_DEFAULT_SG_SEG_CNT,
  	.cmd_per_lun		= LPFC_CMD_PER_LUN,
  	.use_clustering		= ENABLE_CLUSTERING,

Quoted 36 lines · Nicholas A. Bellinger

From: Nicholas Bellinger<[email protected]>

This patch removes the now legacy host_lock unlock() + lock() optimization from lpfc_scsi.c:lpfc_queuecommand(). This also includes setting the SHT->unlocked_qcmd=1 for host_lock less lpfc lpfc_queuecommand() operation.

Signed-off-by Nicholas A. Bellinger<[email protected]>

---
  drivers/scsi/lpfc/lpfc_scsi.c |    4 ++--
  1 files changed, 2 insertions(+), 2 deletions(-)

drivers/scsi/lpfc/lpfc_scsi.c +1 -2

index 2e51aa6..69fe31e 100644
@@ -3023,11 +3023,9 @@ lpfc_queuecommand(struct scsi_cmnd *cmnd, void (*done) (struct scsi_cmnd *))
  		goto out_host_busy_free_buf;
  	}
  	if (phba->cfg_poll&  ENABLE_FCP_RING_POLLING) {
-		spin_unlock(shost->host_lock);
  		lpfc_sli_handle_fast_ring_event(phba,
  			&phba->sli.ring[LPFC_FCP_RING], HA_R0RE_REQ);
 
-		spin_lock(shost->host_lock);
  		if (phba->cfg_poll&  DISABLE_FCP_RING_INT)
  			lpfc_poll_rearm_timer(phba);
  	}

@@ -3723,6 +3721,7 @@ struct scsi_host_template lpfc_template = {
  	.slave_destroy		= lpfc_slave_destroy,
  	.scan_finished		= lpfc_scan_finished,
  	.this_id		= -1,
+	.unlocked_qcmd		= 1,
  	.sg_tablesize		= LPFC_DEFAULT_SG_SEG_CNT,
  	.cmd_per_lun		= LPFC_CMD_PER_LUN,
  	.use_clustering		= ENABLE_CLUSTERING,

drivers/scsi/lpfc/lpfc_scsi.c struct scsi_host_template lpfc_vport_template = { · line 3751

Quoted 7 lines

drivers/scsi/lpfc/lpfc_scsi.c +1 -0

@@ -3746,6 +3745,7 @@ struct scsi_host_template lpfc_vport_template = {
  	.slave_destroy		= lpfc_slave_destroy,
  	.scan_finished		= lpfc_scan_finished,
  	.this_id		= -1,
+	.unlocked_qcmd		= 1,
  	.sg_tablesize		= LPFC_DEFAULT_SG_SEG_CNT,
  	.cmd_per_lun		= LPFC_CMD_PER_LUN,
  	.use_clustering		= ENABLE_CLUSTERING,

The FC class sets the rport state and bits with the host lock held. Drivers were then calling fc_remote_port_chkready from the queuecommand with the host lock held. If we remove the host lock from queuecommand is it possible that the on one proc the fc class calls fc_remote_port_add to re-add a rport, this sets the rport state to online, it unblocks the devices, but then on some other processor we start calling queuecommand and see that the rport is not online (maybe blocked with FC_RPORT_FAST_FAIL_TIMEDOUT set) and so we end up failing the IO?