scsi: mpi3mr: Add io_uring interface support in I/O-polled mode

Add support for the io_uring interface in I/O-polled mode.

This feature is disabled in the driver by default. To enable the feature, a
module parameter "poll_queues" has to be set with the desired number of
polling queues.

When the feature is enabled, the driver reserves a certain number of
operational queue pairs for the poll_queues either from the available queue
pairs or creates additional queue pairs based on the operational queue
availability.

The Polling queues will have corresponding IRQ and ISR functions as similar
to default queues. However, the IRQ line is disabled by the driver for
poll_queues.

Link: https://lore.kernel.org/r/20211220141159.16117-22-sreekanth.reddy@broadcom.com
Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 41 insertions, 5 deletions

diff --git a/drivers/scsi/mpi3mr/mpi3mr_os.c b/drivers/scsi/mpi3mr/mpi3mr_os.c
index d893c6d61a60..8bf1b590cc58 100644
--- a/drivers/scsi/mpi3mr/mpi3mr_os.c
+++ b/drivers/scsi/mpi3mr/mpi3mr_os.c
@@ -3049,17 +3049,49 @@ static int mpi3mr_bios_param(struct scsi_device *sdev,
  * mpi3mr_map_queues - Map queues callback handler
  * @shost: SCSI host reference
  *
- * Call the blk_mq_pci_map_queues with from which operational
- * queue the mapping has to be done
+ * Maps default and poll queues.
  *
- * Return: return of blk_mq_pci_map_queues
+ * Return: return zero.
  */
 static int mpi3mr_map_queues(struct Scsi_Host *shost)
 {
 	struct mpi3mr_ioc *mrioc = shost_priv(shost);
+	int i, qoff, offset;
+	struct blk_mq_queue_map *map = NULL;
+
+	offset = mrioc->op_reply_q_offset;
+
+	for (i = 0, qoff = 0; i < HCTX_MAX_TYPES; i++) {
+		map = &shost->tag_set.map[i];
+
+		map->nr_queues  = 0;
+
+		if (i == HCTX_TYPE_DEFAULT)
+			map->nr_queues = mrioc->default_qcount;
+		else if (i == HCTX_TYPE_POLL)
+			map->nr_queues = mrioc->active_poll_qcount;
+
+		if (!map->nr_queues) {
+			BUG_ON(i == HCTX_TYPE_DEFAULT);
+			continue;
+		}
+
+		/*
+		 * The poll queue(s) doesn't have an IRQ (and hence IRQ
+		 * affinity), so use the regular blk-mq cpu mapping
+		 */
+		map->queue_offset = qoff;
+		if (i != HCTX_TYPE_POLL)
+			blk_mq_pci_map_queues(map, mrioc->pdev, offset);
+		else
+			blk_mq_map_queues(map);
+
+		qoff += map->nr_queues;
+		offset += map->nr_queues;
+	}
+
+	return 0;
 
-	return blk_mq_pci_map_queues(&shost->tag_set.map[HCTX_TYPE_DEFAULT],
-	    mrioc->pdev, mrioc->op_reply_q_offset);
 }
 
 /**
@@ -3873,6 +3905,7 @@ static struct scsi_host_template mpi3mr_driver_template = {
 	.eh_host_reset_handler		= mpi3mr_eh_host_reset,
 	.bios_param			= mpi3mr_bios_param,
 	.map_queues			= mpi3mr_map_queues,
+	.mq_poll                        = mpi3mr_blk_mq_poll,
 	.no_write_same			= 1,
 	.can_queue			= 1,
 	.this_id			= -1,
@@ -4105,6 +4138,9 @@ mpi3mr_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	}
 
 	shost->nr_hw_queues = mrioc->num_op_reply_q;
+	if (mrioc->active_poll_qcount)
+		shost->nr_maps = 3;
+
 	shost->can_queue = mrioc->max_host_ios;
 	shost->sg_tablesize = MPI3MR_SG_DEPTH;
 	shost->max_id = mrioc->facts.max_perids + 1;