[PATCH V2 3/5] scsi: core: implement callback of .complete_queue_affinity

Ming Lei
2019-05-27T15:03:01Z

Implement scsi core's callback of .complete_queue_affinity for
supporting to drain in-flight requests in case that SCSI HBA
supports multiple completion queue.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
drivers/scsi/scsi_lib.c | 14 ++++++++++++++
include/scsi/scsi_host.h | 10 ++++++++++
2 files changed, 24 insertions(+)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 65d0a10c76ad..ac57dc98a8c0 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1750,6 +1750,19 @@ static int scsi_map_queues(struct blk_mq_tag_set *set)
return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
}

+static const struct cpumask *
+scsi_complete_queue_affinity(struct blk_mq_hw_ctx *hctx, int cpu)
+{
+ struct request_queue *q = hctx->queue;
+ struct scsi_device *sdev = q->queuedata;
+ struct Scsi_Host *shost = sdev->host;
+
+ if (shost->hostt->complete_queue_affinity)
+ return shost->hostt->complete_queue_affinity(shost, cpu);
+
+ return NULL;
+}
+
void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
{
struct device *dev = shost->dma_dev;
@@ -1802,6 +1815,7 @@ static const struct blk_mq_ops scsi_mq_ops = {
.initialize_rq_fn = scsi_initialize_rq,
.busy = scsi_mq_lld_busy,
.map_queues = scsi_map_queues,
+ .complete_queue_affinity = scsi_complete_queue_affinity,
};

struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index a5fcdad4a03e..65ccac1429a1 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -268,6 +268,16 @@ struct scsi_host_template {
*/
int (* map_queues)(struct Scsi_Host *shost);

+ /*
+ * This functions lets the driver expose complete queue's cpu
+ * affinity to the block layer. @cpu is used for retrieving
+ * the mapped completion queue.
+ *
+ * Status: OPTIONAL
+ */
+ const struct cpumask * (* complete_queue_affinity)(struct Scsi_Host *,
+ int cpu);
+
/*
* This function determines the BIOS parameters for a given
* harddisk. These tend to be numbers that are made up by
--
2.20.1