scsi: aacraid: Reply queue mapping to CPUs based on IRQ affinity

Fix the I/O hang that arises because of the MSIx vector not having a mapped
online CPU upon receiving completion.

SCSI cmds take the blk_mq route, which is setup during init. Reserved cmds
fetch the vector_no from mq_map after init is complete. Before init, they
have to use 0 - as per the norm.

Reviewed-by: Gilbert Wu <[e-mail]>
Signed-off-by: Sagar Biradar <[e-mail]>
Reviewed-by: John Garry <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/aacraid/aacraid.h

···
 	u32			handle_pci_error;
 	bool			init_reset;
 	u8			soft_reset_support;
+	u8			use_map_queue;
 };
 
 #define aac_adapter_interrupt(dev) \

drivers/scsi/aacraid/commsup.c

···
 struct fib *aac_fib_alloc_tag(struct aac_dev *dev, struct scsi_cmnd *scmd)
 {
 	struct fib *fibptr;
+	u32 blk_tag;
+	int i;
 
-	fibptr = &dev->fibs[scsi_cmd_to_rq(scmd)->tag];
+	blk_tag = blk_mq_unique_tag(scsi_cmd_to_rq(scmd));
+	i = blk_mq_unique_tag_to_tag(blk_tag);
+	fibptr = &dev->fibs[i];
 	/*
 	 *	Null out fields that depend on being zero at the start of
 	 *	each I/O

drivers/scsi/aacraid/linit.c

···
 
 #include <linux/compat.h>
 #include <linux/blkdev.h>
+#include <linux/blk-mq-pci.h>
 #include <linux/completion.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
···
 	sdev->tagged_supported = 1;
 
 	return 0;
+}
+
+static void aac_map_queues(struct Scsi_Host *shost)
+{
+	struct aac_dev *aac = (struct aac_dev *)shost->hostdata;
+
+	blk_mq_pci_map_queues(&shost->tag_set.map[HCTX_TYPE_DEFAULT],
+			      aac->pdev, 0);
+	aac->use_map_queue = true;
 }
 
 /**
···
 	.bios_param			= aac_biosparm,
 	.shost_groups			= aac_host_groups,
 	.slave_configure		= aac_slave_configure,
+	.map_queues			= aac_map_queues,
 	.change_queue_depth		= aac_change_queue_depth,
 	.sdev_groups			= aac_dev_groups,
 	.eh_abort_handler		= aac_eh_abort,
···
 	shost->max_lun = AAC_MAX_LUN;
 
 	pci_set_drvdata(pdev, shost);
+	shost->nr_hw_queues = aac->max_msix;
+	shost->host_tagset = 1;
 
 	error = scsi_add_host(shost, &pdev->dev);
 	if (error)
···
 	struct aac_dev *aac = (struct aac_dev *)shost->hostdata;
 
 	aac_cancel_rescan_worker(aac);
+	aac->use_map_queue = false;
 	scsi_remove_host(shost);
 
 	__aac_shutdown(aac);

drivers/scsi/aacraid/src.c

···
 #endif
 
 	u16 vector_no;
+	struct scsi_cmnd *scmd;
+	u32 blk_tag;
+	struct Scsi_Host *shost = dev->scsi_host_ptr;
+	struct blk_mq_queue_map *qmap;
 
 	atomic_inc(&q->numpending);
 
···
 		if ((dev->comm_interface == AAC_COMM_MESSAGE_TYPE3)
 			&& dev->sa_firmware)
 			vector_no = aac_get_vector(dev);
-		else
-			vector_no = fib->vector_no;
+		else {
+			if (!fib->vector_no || !fib->callback_data) {
+				if (shost && dev->use_map_queue) {
+					qmap = &shost->tag_set.map[HCTX_TYPE_DEFAULT];
+					vector_no = qmap->mq_map[raw_smp_processor_id()];
+				}
+				/*
+				 *	We hardcode the vector_no for
+				 *	reserved commands as a valid shost is
+				 *	absent during the init
+				 */
+				else
+					vector_no = 0;
+			} else {
+				scmd = (struct scsi_cmnd *)fib->callback_data;
+				blk_tag = blk_mq_unique_tag(scsi_cmd_to_rq(scmd));
+				vector_no = blk_mq_unique_tag_to_hwq(blk_tag);
+			}
+		}
 
 		if (native_hba) {
 			if (fib->flags & FIB_CONTEXT_FLAG_NATIVE_HBA_TMF) {