Re: [PATCH v1 1/3] add io_uring with IOPOLL support in scsi layer
From: John Garry <hidden>
Date: 2020-12-01 09:50:58
Also in:
linux-scsi
On 30/11/2020 07:41, Kashyap Desai wrote:
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diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index72b12102f777..5a3c383a2bb3 100644--- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c@@ -1766,6 +1766,19 @@ static void scsi_mq_exit_request(structblk_mq_tag_set *set, struct request *rq,quoted
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).
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--- 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 */quoted
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+ + 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