On 15/10/2020 14:36, Kashyap Desai wrote:
io_uring with IOPOLL is not currently supported in scsi mid layer.
Outside of that everything else should work and no extra support in the driver is needed.
Currently io_uring with IOPOLL support is only available in block layer.
This patch is to extend support of mq_poll in scsi layer. >
Signed-off-by: Kashyap Desai <kashyap.desai@xxxxxxxxxxxx>
Cc: sumit.saxena@xxxxxxxxxxxx
Cc: chandrakanth.patil@xxxxxxxxxxxx
Cc: linux-block@xxxxxxxxxxxxxxx
---
drivers/scsi/scsi_lib.c | 16 ++++++++++++++++
include/scsi/scsi_cmnd.h | 1 +
include/scsi/scsi_host.h | 11 +++++++++++
3 files changed, 28 insertions(+)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 72b12102f777..5a3c383a2bb3 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1766,6 +1766,19 @@ static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
cmd->sense_buffer);
}
+
+static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx)
+{
+ struct request_queue *q = hctx->queue;
+ struct scsi_device *sdev = q->queuedata;
+ struct Scsi_Host *shost = sdev->host;
could we separately set hctx->driver_data = shost or similar for a
quicker lookup? I don't see hctx->driver_data set for SCSI currently.
Going through the scsi_device looks strange - I know that it is done in
scsi_commit_rqs.
+
+ if (shost->hostt->mq_poll)
to avoid this check, could we reject if .mq_poll is not set and
HCTX_TYPE_POLL is?
+ return shost->hostt->mq_poll(shost, hctx->queue_num);
+
+ return 0;
+}
+
static int scsi_map_queues(struct blk_mq_tag_set *set)
{
struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
@@ -1833,6 +1846,7 @@ static const struct blk_mq_ops scsi_mq_ops_no_commit = {
.cleanup_rq = scsi_cleanup_rq,
.busy = scsi_mq_lld_busy,
.map_queues = scsi_map_queues,
+ .poll = scsi_mq_poll,
};
@@ -1861,6 +1875,7 @@ static const struct blk_mq_ops scsi_mq_ops = {
.cleanup_rq = scsi_cleanup_rq,
.busy = scsi_mq_lld_busy,
.map_queues = scsi_map_queues,
+ .poll = scsi_mq_poll,
};
struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
@@ -1893,6 +1908,7 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost)
else
tag_set->ops = &scsi_mq_ops_no_commit;
tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
+ tag_set->nr_maps = shost->nr_maps ? : 1;
tag_set->queue_depth = shost->can_queue;
tag_set->cmd_size = cmd_size;
tag_set->numa_node = NUMA_NO_NODE;
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index e76bac4d14c5..5844374a85b1 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -9,6 +9,7 @@
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/scatterlist.h>
+#include <scsi/scsi_host.h>
can we maintain alphabetic ordering?
#include <scsi/scsi_device.h>
#include <scsi/scsi_request.h>
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 701f178b20ae..905ee6b00c55 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -270,6 +270,16 @@ struct scsi_host_template {
*/
int (* map_queues)(struct Scsi_Host *shost);
+ /*
+ * SCSI interface of blk_poll - poll for IO completions.
+ * Possible interface only if scsi LLD expose multiple h/w queues.
+ *
+ * Return values: Number of completed entries found.
/s/values/value/
+ *
+ * Status: OPTIONAL
+ */
+ int (* mq_poll)(struct Scsi_Host *shost, unsigned int queue_num);
+
/*
* Check if scatterlists need to be padded for DMA draining.
*
@@ -610,6 +620,7 @@ struct Scsi_Host {
* the total queue depth is can_queue.
*/
unsigned nr_hw_queues;
+ unsigned nr_maps; > unsigned active_mode:2;
unsigned unchecked_isa_dma:1;
