diff mbox series

[v1,1/3] add io_uring with IOPOLL support in scsi layer

Message ID 20201015133633.61836-1-kashyap.desai@broadcom.com (mailing list archive)
State New, archived
Headers show
Series io_uring iopoll in scsi layer | expand

Commit Message

Kashyap Desai Oct. 15, 2020, 1:36 p.m. UTC
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@broadcom.com>
Cc: sumit.saxena@broadcom.com
Cc: chandrakanth.patil@broadcom.com
Cc: linux-block@vger.kernel.org

---
 drivers/scsi/scsi_lib.c  | 16 ++++++++++++++++
 include/scsi/scsi_cmnd.h |  1 +
 include/scsi/scsi_host.h | 11 +++++++++++
 3 files changed, 28 insertions(+)

Comments

John Garry Nov. 13, 2020, 11:51 a.m. UTC | #1
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@broadcom.com>
> Cc: sumit.saxena@broadcom.com
> Cc: chandrakanth.patil@broadcom.com
> Cc: linux-block@vger.kernel.org
> 
> ---
>   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;
>   
>
Hannes Reinecke Nov. 20, 2020, 7:16 a.m. UTC | #2
On 10/15/20 3:36 PM, 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@broadcom.com>
> Cc: sumit.saxena@broadcom.com
> Cc: chandrakanth.patil@broadcom.com
> Cc: linux-block@vger.kernel.org
> 
> ---
>   drivers/scsi/scsi_lib.c  | 16 ++++++++++++++++
>   include/scsi/scsi_cmnd.h |  1 +
>   include/scsi/scsi_host.h | 11 +++++++++++
>   3 files changed, 28 insertions(+)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
Kashyap Desai Nov. 30, 2020, 7:41 a.m. UTC | #3
> > 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.

John - I have included your comments. Below is add-on patch which handles
all your comment except one.
Below is just compiled (not tested patch). Please let me know if you like to
handle "scsi_init_hctx" in this patch or shall we do it as a separate patch
(out of this patch series.) ?


--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1769,9 +1769,7 @@ static void scsi_mq_exit_request(struct blk_mq_tag_set
*set, struct request *rq,

 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;
+       struct Scsi_Host *shost = hctx->driver_data;

        if (shost->hostt->mq_poll)
                return shost->hostt->mq_poll(shost, hctx->queue_num);
@@ -1779,6 +1777,14 @@ static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx)
        return 0;
 }

+static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
+                         unsigned int hctx_idx)
+{
+       struct Scsi_Host *shost = data;
+       hctx->driver_data = shost;
+       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);
@@ -1846,6 +1852,7 @@ 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,
+       .init_hctx      = scsi_init_hctx,
        .poll           = scsi_mq_poll,
 };

@@ -1875,6 +1882,7 @@ static const struct blk_mq_ops scsi_mq_ops = {
        .cleanup_rq     = scsi_cleanup_rq,
        .busy           = scsi_mq_lld_busy,
        .map_queues     = scsi_map_queues,
+       .init_hctx      = scsi_init_hctx,
        .poll           = scsi_mq_poll,
 };

diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 5844374a85b1..cc30df96f5f7 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -9,8 +9,8 @@
 #include <linux/types.h>
 #include <linux/timer.h>
 #include <linux/scatterlist.h>
-#include <scsi/scsi_host.h>
 #include <scsi/scsi_device.h>
+#include <scsi/scsi_host.h>
 #include <scsi/scsi_request.h>

 struct Scsi_Host;
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 905ee6b00c55..a0cda0f66b84 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -274,7 +274,7 @@ struct scsi_host_template {
         * 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.
+        * Return value: Number of completed entries found.
         *
         * Status: OPTIONAL
         */

>
> > +
> > +	if (shost->hostt->mq_poll)
>
> to avoid this check, could we reject if .mq_poll is not set and
> HCTX_TYPE_POLL is?

Is this urgent or shall we improve later ? I am not able to figure out how
you want to manage this ? Can you explain little bit ?

Kashyap

>
> > +		return shost->hostt->mq_poll(shost, hctx->queue_num);
> > +
> > +	return 0;
> > +}
John Garry Dec. 1, 2020, 9:49 a.m. UTC | #4
On 30/11/2020 07:41, Kashyap Desai wrote:
>>> 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.
> John - I have included your comments. Below is add-on patch which handles
> all your comment except one.
> Below is just compiled (not tested patch). Please let me know if you like to
> handle "scsi_init_hctx" in this patch or shall we do it as a separate patch
> (out of this patch series.) ?

It might be better as a separate patch if you also change 
scsi_commit_rqs() to use hctx->driver_data, which you are currently not 
doing (or showing here).

> 
> 
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -1769,9 +1769,7 @@ static void scsi_mq_exit_request(struct blk_mq_tag_set
> *set, struct request *rq,
> 
>   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;
> +       struct Scsi_Host *shost = hctx->driver_data;
> 
>          if (shost->hostt->mq_poll)
>                  return shost->hostt->mq_poll(shost, hctx->queue_num);
> @@ -1779,6 +1777,14 @@ static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx)
>          return 0;
>   }
> 
> +static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
> +                         unsigned int hctx_idx)
> +{
> +       struct Scsi_Host *shost = data;
> +       hctx->driver_data = shost;
> +       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);
> @@ -1846,6 +1852,7 @@ 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,
> +       .init_hctx      = scsi_init_hctx,
>          .poll           = scsi_mq_poll,
>   };
> 
> @@ -1875,6 +1882,7 @@ static const struct blk_mq_ops scsi_mq_ops = {
>          .cleanup_rq     = scsi_cleanup_rq,
>          .busy           = scsi_mq_lld_busy,
>          .map_queues     = scsi_map_queues,
> +       .init_hctx      = scsi_init_hctx,
>          .poll           = scsi_mq_poll,
>   };
> 
> diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
> index 5844374a85b1..cc30df96f5f7 100644
> --- a/include/scsi/scsi_cmnd.h
> +++ b/include/scsi/scsi_cmnd.h
> @@ -9,8 +9,8 @@
>   #include <linux/types.h>
>   #include <linux/timer.h>
>   #include <linux/scatterlist.h>
> -#include <scsi/scsi_host.h>
>   #include <scsi/scsi_device.h>
> +#include <scsi/scsi_host.h>
>   #include <scsi/scsi_request.h>
> 
>   struct Scsi_Host;
> diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
> index 905ee6b00c55..a0cda0f66b84 100644
> --- a/include/scsi/scsi_host.h
> +++ b/include/scsi/scsi_host.h
> @@ -274,7 +274,7 @@ struct scsi_host_template {
>           * 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.
> +        * Return value: Number of completed entries found.
>           *
>           * Status: OPTIONAL
>           */
> 
>>> +
>>> +	if (shost->hostt->mq_poll)
>> to avoid this check, could we reject if .mq_poll is not set and
>> HCTX_TYPE_POLL is?
> Is this urgent or shall we improve later ? I am not able to figure out how
> you want to manage this ? Can you explain little bit ?

I don't think that it will make much overhead difference, so ok to omit 
for now if more trouble than it's worth to implement.

Thanks,
John
diff mbox series

Patch

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;
+
+	if (shost->hostt->mq_poll)
+		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>
 #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.
+	 *
+	 * 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;