scsi: lpfc: Change lpfc_nodelist save_flags member into a bitmask

In attempt to reduce the amount of unnecessary ndlp->lock acquisitions in
the lpfc driver, change save_flags into an unsigned long bitmask and use
clear_bit/test_bit bitwise atomic APIs instead of reliance on ndlp->lock
for synchronization.

Signed-off-by: Justin Tee <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin K. Petersen <[email protected]>

Author: Justin Tee

drivers/scsi/lpfc/lpfc_ct.c

@@ -1646,14 +1646,12 @@ lpfc_cmpl_ct(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 	/* If the caller wanted a synchronous DA_ID completion, signal the
 	 * wait obj and clear flag to reset the vport.
 	 */
-	if (ndlp->save_flags & NLP_WAIT_FOR_DA_ID) {
+	if (test_bit(NLP_WAIT_FOR_DA_ID, &ndlp->save_flags)) {
 		if (ndlp->da_id_waitq)
 			wake_up(ndlp->da_id_waitq);
 	}
 
-	spin_lock_irq(&ndlp->lock);
-	ndlp->save_flags &= ~NLP_WAIT_FOR_DA_ID;
-	spin_unlock_irq(&ndlp->lock);
+	clear_bit(NLP_WAIT_FOR_DA_ID, &ndlp->save_flags);
 
 	lpfc_ct_free_iocb(phba, cmdiocb);
 	lpfc_nlp_put(ndlp);

drivers/scsi/lpfc/lpfc_disc.h

@@ -85,13 +85,13 @@ enum lpfc_fc4_xpt_flags {
 	NLP_XPT_HAS_HH		= 0x10
 };
 
-enum lpfc_nlp_save_flags {
+enum lpfc_nlp_save_flags { /* mask bits */
 	/* devloss occurred during recovery */
-	NLP_IN_RECOV_POST_DEV_LOSS	= 0x1,
+	NLP_IN_RECOV_POST_DEV_LOSS,
 	/* wait for outstanding LOGO to cmpl */
-	NLP_WAIT_FOR_LOGO		= 0x2,
+	NLP_WAIT_FOR_LOGO,
 	/* wait for outstanding DA_ID to finish */
-	NLP_WAIT_FOR_DA_ID              = 0x4
+	NLP_WAIT_FOR_DA_ID
 };
 
 struct lpfc_nodelist {
@@ -154,7 +154,7 @@ struct lpfc_nodelist {
 	uint32_t fc4_prli_sent;
 
 	/* flags to keep ndlp alive until special conditions are met */
-	enum lpfc_nlp_save_flags save_flags;
+	unsigned long save_flags;
 
 	enum lpfc_fc4_xpt_flags fc4_xpt_flags;
 

drivers/scsi/lpfc/lpfc_els.c

@@ -2988,12 +2988,8 @@ lpfc_cmpl_els_logo(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 	}
 
 	clear_bit(NLP_LOGO_SND, &ndlp->nlp_flag);
-	spin_lock_irq(&ndlp->lock);
-	if (ndlp->save_flags & NLP_WAIT_FOR_LOGO) {
+	if (test_and_clear_bit(NLP_WAIT_FOR_LOGO, &ndlp->save_flags))
 		wake_up_waiter = 1;
-		ndlp->save_flags &= ~NLP_WAIT_FOR_LOGO;
-	}
-	spin_unlock_irq(&ndlp->lock);
 
 	lpfc_debugfs_disc_trc(vport, LPFC_DISC_TRC_ELS_CMD,
 		"LOGO cmpl:       status:x%x/x%x did:x%x",
@@ -11509,15 +11505,13 @@ lpfc_cmpl_els_npiv_logo(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 		lpfc_can_disctmo(vport);
 	}
 
-	if (ndlp->save_flags & NLP_WAIT_FOR_LOGO) {
+	if (test_bit(NLP_WAIT_FOR_LOGO, &ndlp->save_flags)) {
 		/* Wake up lpfc_vport_delete if waiting...*/
 		if (ndlp->logo_waitq)
 			wake_up(ndlp->logo_waitq);
 		clear_bit(NLP_ISSUE_LOGO, &ndlp->nlp_flag);
 		clear_bit(NLP_LOGO_SND, &ndlp->nlp_flag);
-		spin_lock_irq(&ndlp->lock);
-		ndlp->save_flags &= ~NLP_WAIT_FOR_LOGO;
-		spin_unlock_irq(&ndlp->lock);
+		clear_bit(NLP_WAIT_FOR_LOGO, &ndlp->save_flags);
 	}
 
 	/* Safe to release resources now. */

drivers/scsi/lpfc/lpfc_hbadisc.c

@@ -414,22 +414,15 @@ void
 lpfc_check_nlp_post_devloss(struct lpfc_vport *vport,
 			    struct lpfc_nodelist *ndlp)
 {
-	unsigned long iflags;
-
-	spin_lock_irqsave(&ndlp->lock, iflags);
-	if (ndlp->save_flags & NLP_IN_RECOV_POST_DEV_LOSS) {
-		ndlp->save_flags &= ~NLP_IN_RECOV_POST_DEV_LOSS;
-		spin_unlock_irqrestore(&ndlp->lock, iflags);
+	if (test_and_clear_bit(NLP_IN_RECOV_POST_DEV_LOSS, &ndlp->save_flags)) {
 		lpfc_nlp_get(ndlp);
 		lpfc_printf_vlog(vport, KERN_INFO, LOG_DISCOVERY | LOG_NODE,
 				 "8438 Devloss timeout reversed on DID x%x "
 				 "refcnt %d ndlp %p flag x%lx "
 				 "port_state = x%x\n",
 				 ndlp->nlp_DID, kref_read(&ndlp->kref), ndlp,
 				 ndlp->nlp_flag, vport->port_state);
-		return;
 	}
-	spin_unlock_irqrestore(&ndlp->lock, iflags);
 }
 
 /**
@@ -546,9 +539,7 @@ lpfc_dev_loss_tmo_handler(struct lpfc_nodelist *ndlp)
 					 ndlp->nlp_DID, kref_read(&ndlp->kref),
 					 ndlp, ndlp->nlp_flag,
 					 vport->port_state);
-			spin_lock_irqsave(&ndlp->lock, iflags);
-			ndlp->save_flags |= NLP_IN_RECOV_POST_DEV_LOSS;
-			spin_unlock_irqrestore(&ndlp->lock, iflags);
+			set_bit(NLP_IN_RECOV_POST_DEV_LOSS, &ndlp->save_flags);
 			return fcf_inuse;
 		} else if (ndlp->nlp_state == NLP_STE_UNMAPPED_NODE) {
 			/* Fabric node fully recovered before this dev_loss_tmo

drivers/scsi/lpfc/lpfc_init.c

@@ -3847,8 +3847,8 @@ lpfc_offline_prep(struct lpfc_hba *phba, int mbx_action)
 					 * Otherwise, let dev_loss take care of
 					 * the node.
 					 */
-					if (!(ndlp->save_flags &
-					      NLP_IN_RECOV_POST_DEV_LOSS) &&
+					if (!test_bit(NLP_IN_RECOV_POST_DEV_LOSS,
+						      &ndlp->save_flags) &&
 					    !(ndlp->fc4_xpt_flags &
 					      (NVME_XPT_REGD | SCSI_XPT_REGD)))
 						lpfc_disc_state_machine

drivers/scsi/lpfc/lpfc_scsi.c

@@ -6120,31 +6120,28 @@ lpfc_target_reset_handler(struct scsi_cmnd *cmnd)
 
 		/* Issue LOGO, if no LOGO is outstanding */
 		spin_lock_irqsave(&pnode->lock, flags);
-		if (!(pnode->save_flags & NLP_WAIT_FOR_LOGO) &&
+		if (!test_bit(NLP_WAIT_FOR_LOGO, &pnode->save_flags) &&
 		    !pnode->logo_waitq) {
 			pnode->logo_waitq = &waitq;
 			pnode->nlp_fcp_info &= ~NLP_FCP_2_DEVICE;
-			set_bit(NLP_ISSUE_LOGO, &pnode->nlp_flag);
-			pnode->save_flags |= NLP_WAIT_FOR_LOGO;
 			spin_unlock_irqrestore(&pnode->lock, flags);
+			set_bit(NLP_ISSUE_LOGO, &pnode->nlp_flag);
+			set_bit(NLP_WAIT_FOR_LOGO, &pnode->save_flags);
 			lpfc_unreg_rpi(vport, pnode);
 			wait_event_timeout(waitq,
-					   (!(pnode->save_flags &
-					      NLP_WAIT_FOR_LOGO)),
+					   !test_bit(NLP_WAIT_FOR_LOGO,
+						     &pnode->save_flags),
 					   msecs_to_jiffies(dev_loss_tmo *
 							    1000));
 
-			if (pnode->save_flags & NLP_WAIT_FOR_LOGO) {
+			if (test_and_clear_bit(NLP_WAIT_FOR_LOGO,
+					       &pnode->save_flags))
 				lpfc_printf_vlog(vport, KERN_ERR, logit,
 						 "0725 SCSI layer TGTRST "
 						 "failed & LOGO TMO (%d, %llu) "
 						 "return x%x\n",
 						 tgt_id, lun_id, status);
-				spin_lock_irqsave(&pnode->lock, flags);
-				pnode->save_flags &= ~NLP_WAIT_FOR_LOGO;
-			} else {
-				spin_lock_irqsave(&pnode->lock, flags);
-			}
+			spin_lock_irqsave(&pnode->lock, flags);
 			pnode->logo_waitq = NULL;
 			spin_unlock_irqrestore(&pnode->lock, flags);
 			status = SUCCESS;

drivers/scsi/lpfc/lpfc_vport.c

@@ -492,21 +492,22 @@ lpfc_send_npiv_logo(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(waitq);
 
 	spin_lock_irq(&ndlp->lock);
-	if (!(ndlp->save_flags & NLP_WAIT_FOR_LOGO) &&
+	if (!test_bit(NLP_WAIT_FOR_LOGO, &ndlp->save_flags) &&
 	    !ndlp->logo_waitq) {
 		ndlp->logo_waitq = &waitq;
 		ndlp->nlp_fcp_info &= ~NLP_FCP_2_DEVICE;
 		set_bit(NLP_ISSUE_LOGO, &ndlp->nlp_flag);
-		ndlp->save_flags |= NLP_WAIT_FOR_LOGO;
+		set_bit(NLP_WAIT_FOR_LOGO, &ndlp->save_flags);
 	}
 	spin_unlock_irq(&ndlp->lock);
 	rc = lpfc_issue_els_npiv_logo(vport, ndlp);
 	if (!rc) {
 		wait_event_timeout(waitq,
-				   (!(ndlp->save_flags & NLP_WAIT_FOR_LOGO)),
+				   !test_bit(NLP_WAIT_FOR_LOGO,
+					     &ndlp->save_flags),
 				   msecs_to_jiffies(phba->fc_ratov * 2000));
 
-		if (!(ndlp->save_flags & NLP_WAIT_FOR_LOGO))
+		if (!test_bit(NLP_WAIT_FOR_LOGO, &ndlp->save_flags))
 			goto logo_cmpl;
 		/* LOGO wait failed.  Correct status. */
 		rc = -EINTR;
@@ -516,9 +517,7 @@ lpfc_send_npiv_logo(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 
 	/* Error - clean up node flags. */
 	clear_bit(NLP_ISSUE_LOGO, &ndlp->nlp_flag);
-	spin_lock_irq(&ndlp->lock);
-	ndlp->save_flags &= ~NLP_WAIT_FOR_LOGO;
-	spin_unlock_irq(&ndlp->lock);
+	clear_bit(NLP_WAIT_FOR_LOGO, &ndlp->save_flags);
 
  logo_cmpl:
 	lpfc_printf_vlog(vport, KERN_INFO, LOG_VPORT,
@@ -696,19 +695,20 @@ lpfc_vport_delete(struct fc_vport *fc_vport)
 
 			spin_lock_irq(&ndlp->lock);
 			ndlp->da_id_waitq = &waitq;
-			ndlp->save_flags |= NLP_WAIT_FOR_DA_ID;
 			spin_unlock_irq(&ndlp->lock);
+			set_bit(NLP_WAIT_FOR_DA_ID, &ndlp->save_flags);
 
 			rc = lpfc_ns_cmd(vport, SLI_CTNS_DA_ID, 0, 0);
 			if (!rc) {
 				wait_event_timeout(waitq,
-				   !(ndlp->save_flags & NLP_WAIT_FOR_DA_ID),
+				   !test_bit(NLP_WAIT_FOR_DA_ID,
+					     &ndlp->save_flags),
 				   msecs_to_jiffies(phba->fc_ratov * 2000));
 			}
 
 			lpfc_printf_vlog(vport, KERN_INFO, LOG_VPORT | LOG_ELS,
 					 "1829 DA_ID issue status %d. "
-					 "SFlag x%x NState x%x, NFlag x%lx "
+					 "SFlag x%lx NState x%x, NFlag x%lx "
 					 "Rpi x%x\n",
 					 rc, ndlp->save_flags, ndlp->nlp_state,
 					 ndlp->nlp_flag, ndlp->nlp_rpi);
@@ -718,8 +718,8 @@ lpfc_vport_delete(struct fc_vport *fc_vport)
 			 */
 			spin_lock_irq(&ndlp->lock);
 			ndlp->da_id_waitq = NULL;
-			ndlp->save_flags &= ~NLP_WAIT_FOR_DA_ID;
 			spin_unlock_irq(&ndlp->lock);
+			clear_bit(NLP_WAIT_FOR_DA_ID, &ndlp->save_flags);
 		}
 
 issue_logo: