scsi: lpfc: Replace blk_irq_poll intr handler with threaded IRQ

It has been determined that the threaded IRQ API accomplishes effectively
the same performance metrics as blk_irq_poll.  As blk_irq_poll is mostly
scheduled by the softirqd and handled in softirq context, this is not
entirely desired from a Fibre Channel driver context.  A threaded IRQ model
fits cleaner.  This patch replaces the blk_irq_poll logic with threaded
IRQ.
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Link: https://lore.kernel.org/r/20230417191558.83100-7-justintee8345@gmail.comSigned-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_crtn.h

@@ -247,6 +247,7 @@ irqreturn_t lpfc_sli_sp_intr_handler(int, void *);
 irqreturn_t lpfc_sli_fp_intr_handler(int, void *);
 irqreturn_t lpfc_sli4_intr_handler(int, void *);
 irqreturn_t lpfc_sli4_hba_intr_handler(int, void *);
+irqreturn_t lpfc_sli4_hba_intr_handler_th(int irq, void *dev_id);
 
 int lpfc_read_object(struct lpfc_hba *phba, char *s, uint32_t *datap,
 		     uint32_t len);

drivers/scsi/lpfc/lpfc_init.c

@@ -1279,7 +1279,7 @@ lpfc_hb_mbox_cmpl(struct lpfc_hba * phba, LPFC_MBOXQ_t * pmboxq)
 /*
  * lpfc_idle_stat_delay_work - idle_stat tracking
  *
- * This routine tracks per-cq idle_stat and determines polling decisions.
+ * This routine tracks per-eq idle_stat and determines polling decisions.
  *
  * Return codes:
  *   None
@@ -1290,7 +1290,7 @@ lpfc_idle_stat_delay_work(struct work_struct *work)
 	struct lpfc_hba *phba = container_of(to_delayed_work(work),
 					     struct lpfc_hba,
 					     idle_stat_delay_work);
-	struct lpfc_queue *cq;
+	struct lpfc_queue *eq;
 	struct lpfc_sli4_hdw_queue *hdwq;
 	struct lpfc_idle_stat *idle_stat;
 	u32 i, idle_percent;
@@ -1306,10 +1306,10 @@ lpfc_idle_stat_delay_work(struct work_struct *work)
 
 	for_each_present_cpu(i) {
 		hdwq = &phba->sli4_hba.hdwq[phba->sli4_hba.cpu_map[i].hdwq];
-		cq = hdwq->io_cq;
+		eq = hdwq->hba_eq;
 
-		/* Skip if we've already handled this cq's primary CPU */
-		if (cq->chann != i)
+		/* Skip if we've already handled this eq's primary CPU */
+		if (eq->chann != i)
 			continue;
 
 		idle_stat = &phba->sli4_hba.idle_stat[i];
@@ -1333,9 +1333,9 @@ lpfc_idle_stat_delay_work(struct work_struct *work)
 		idle_percent = 100 - idle_percent;
 
 		if (idle_percent < 15)
-			cq->poll_mode = LPFC_QUEUE_WORK;
+			eq->poll_mode = LPFC_QUEUE_WORK;
 		else
-			cq->poll_mode = LPFC_IRQ_POLL;
+			eq->poll_mode = LPFC_THREADED_IRQ;
 
 		idle_stat->prev_idle = wall_idle;
 		idle_stat->prev_wall = wall;
@@ -4357,6 +4357,7 @@ lpfc_io_buf_replenish(struct lpfc_hba *phba, struct list_head *cbuf)
 	struct lpfc_sli4_hdw_queue *qp;
 	struct lpfc_io_buf *lpfc_cmd;
 	int idx, cnt;
+	unsigned long iflags;
 
 	qp = phba->sli4_hba.hdwq;
 	cnt = 0;
@@ -4371,12 +4372,13 @@ lpfc_io_buf_replenish(struct lpfc_hba *phba, struct list_head *cbuf)
 			lpfc_cmd->hdwq_no = idx;
 			lpfc_cmd->hdwq = qp;
 			lpfc_cmd->cur_iocbq.cmd_cmpl = NULL;
-			spin_lock(&qp->io_buf_list_put_lock);
+			spin_lock_irqsave(&qp->io_buf_list_put_lock, iflags);
 			list_add_tail(&lpfc_cmd->list,
 				      &qp->lpfc_io_buf_list_put);
 			qp->put_io_bufs++;
 			qp->total_io_bufs++;
-			spin_unlock(&qp->io_buf_list_put_lock);
+			spin_unlock_irqrestore(&qp->io_buf_list_put_lock,
+					       iflags);
 		}
 	}
 	return cnt;
@@ -13117,8 +13119,10 @@ lpfc_sli4_enable_msix(struct lpfc_hba *phba)
 		}
 		eqhdl->irq = rc;
 
-		rc = request_irq(eqhdl->irq, &lpfc_sli4_hba_intr_handler, 0,
-				 name, eqhdl);
+		rc = request_threaded_irq(eqhdl->irq,
+					  &lpfc_sli4_hba_intr_handler,
+					  &lpfc_sli4_hba_intr_handler_th,
+					  IRQF_ONESHOT, name, eqhdl);
 		if (rc) {
 			lpfc_printf_log(phba, KERN_WARNING, LOG_INIT,
 					"0486 MSI-X fast-path (%d) "

drivers/scsi/lpfc/lpfc_sli4.h

@@ -140,7 +140,7 @@ struct lpfc_rqb {
 
 enum lpfc_poll_mode {
 	LPFC_QUEUE_WORK,
-	LPFC_IRQ_POLL
+	LPFC_THREADED_IRQ,
 };
 
 struct lpfc_idle_stat {
@@ -279,8 +279,6 @@ struct lpfc_queue {
 	struct list_head _poll_list;
 	void **q_pgs;	/* array to index entries per page */
 
-#define LPFC_IRQ_POLL_WEIGHT 256
-	struct irq_poll iop;
 	enum lpfc_poll_mode poll_mode;
 };