It is enough to just check if we can get the budget via .get_budget().
And we don't need to deal with device state change in .get_budget().
For SCSI, one issue to be fixed is that we have to call scsi_mq_uninit_cmd()
to free allocated ressources if SCSI device fails to handle the request. And
it isn't enough to simply call blk_mq_end_request() to do that if this request
is marked as RQF_DONTPREP.
Fixes: 0df21c86bdbf(scsi: implement .get_budget and .put_budget for blk-mq)
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
block/blk-mq-sched.c | 14 ++------------
block/blk-mq.c | 17 ++++-------------
block/blk-mq.h | 5 ++---
drivers/scsi/scsi_lib.c | 11 +++--------
include/linux/blk-mq.h | 2 +-
5 files changed, 12 insertions(+), 37 deletions(-)
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 7775f6b12fa9..13a27d4d1671 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -94,23 +94,18 @@ static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
do {
struct request *rq;
- blk_status_t ret;
if (e->type->ops.mq.has_work &&
!e->type->ops.mq.has_work(hctx))
break;
- ret = blk_mq_get_dispatch_budget(hctx);
- if (ret == BLK_STS_RESOURCE)
+ if (!blk_mq_get_dispatch_budget(hctx))
break;
rq = e->type->ops.mq.dispatch_request(hctx);
if (!rq) {
blk_mq_put_dispatch_budget(hctx);
break;
- } else if (ret != BLK_STS_OK) {
- blk_mq_end_request(rq, ret);
- continue;
}
/*
@@ -146,22 +141,17 @@ static void blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
do {
struct request *rq;
- blk_status_t ret;
if (!sbitmap_any_bit_set(&hctx->ctx_map))
break;
- ret = blk_mq_get_dispatch_budget(hctx);
- if (ret == BLK_STS_RESOURCE)
+ if (!blk_mq_get_dispatch_budget(hctx))
break;
rq = blk_mq_dequeue_from_ctx(hctx, ctx);
if (!rq) {
blk_mq_put_dispatch_budget(hctx);
break;
- } else if (ret != BLK_STS_OK) {
- blk_mq_end_request(rq, ret);
- continue;
}
/*
diff --git a/block/blk-mq.c b/block/blk-mq.c
index e4d2490f4e7e..f4e1d8447b5d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1134,13 +1134,8 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
}
}
- if (!got_budget) {
- ret = blk_mq_get_dispatch_budget(hctx);
- if (ret == BLK_STS_RESOURCE)
- break;
- if (ret != BLK_STS_OK)
- goto fail_rq;
- }
+ if (!got_budget && !blk_mq_get_dispatch_budget(hctx))
+ break;
list_del_init(&rq->queuelist);
@@ -1167,7 +1162,6 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
break;
}
- fail_rq:
if (unlikely(ret != BLK_STS_OK)) {
errors++;
blk_mq_end_request(rq, BLK_STS_IOERR);
@@ -1639,12 +1633,10 @@ static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
if (!blk_mq_get_driver_tag(rq, NULL, false))
goto insert;
- ret = blk_mq_get_dispatch_budget(hctx);
- if (ret == BLK_STS_RESOURCE) {
+ if (!blk_mq_get_dispatch_budget(hctx)) {
blk_mq_put_driver_tag(rq);
goto insert;
- } else if (ret != BLK_STS_OK)
- goto fail_rq;
+ }
new_cookie = request_to_qc_t(hctx, rq);
@@ -1662,7 +1654,6 @@ static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
__blk_mq_requeue_request(rq);
goto insert;
default:
- fail_rq:
*cookie = BLK_QC_T_NONE;
blk_mq_end_request(rq, ret);
return;
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 522b420dedc0..f97aceff76e9 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -147,14 +147,13 @@ static inline void blk_mq_put_dispatch_budget(struct blk_mq_hw_ctx *hctx)
q->mq_ops->put_budget(hctx);
}
-static inline blk_status_t blk_mq_get_dispatch_budget(
- struct blk_mq_hw_ctx *hctx)
+static inline bool blk_mq_get_dispatch_budget(struct blk_mq_hw_ctx *hctx)
{
struct request_queue *q = hctx->queue;
if (q->mq_ops->get_budget)
return q->mq_ops->get_budget(hctx);
- return BLK_STS_OK;
+ return true;
}
#endif
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 7f218ef61900..c537c4d768c1 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1949,27 +1949,22 @@ static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
put_device(&sdev->sdev_gendev);
}
-static blk_status_t scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
+static bool scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
{
struct request_queue *q = hctx->queue;
struct scsi_device *sdev = q->queuedata;
- blk_status_t ret;
-
- ret = prep_to_mq(scsi_prep_state_check(sdev, NULL));
- if (ret == BLK_STS_RESOURCE || ret != BLK_STS_OK)
- return ret;
if (!get_device(&sdev->sdev_gendev))
goto out;
if (!scsi_dev_queue_ready(q, sdev))
goto out_put_device;
- return BLK_STS_OK;
+ return true;
out_put_device:
put_device(&sdev->sdev_gendev);
out:
- return BLK_STS_RESOURCE;
+ return false;
}
static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index e5e6becd57d3..439a7970ed5d 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -92,7 +92,7 @@ struct blk_mq_queue_data {
typedef blk_status_t (queue_rq_fn)(struct blk_mq_hw_ctx *,
const struct blk_mq_queue_data *);
-typedef blk_status_t (get_budget_fn)(struct blk_mq_hw_ctx *);
+typedef bool (get_budget_fn)(struct blk_mq_hw_ctx *);
typedef void (put_budget_fn)(struct blk_mq_hw_ctx *);
typedef enum blk_eh_timer_return (timeout_fn)(struct request *, bool);
typedef int (init_hctx_fn)(struct blk_mq_hw_ctx *, void *, unsigned int);
--
2.9.5
