@@ -239,13 +239,8 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error)
error = fq->rq_status;
hctx = flush_rq->mq_hctx;
- if (!q->elevator) {
- blk_mq_tag_set_rq(hctx, flush_rq->tag, fq->orig_rq);
- flush_rq->tag = -1;
- } else {
- blk_mq_put_driver_tag(flush_rq);
- flush_rq->internal_tag = -1;
- }
+ flush_rq->internal_tag = -1;
+ blk_mq_put_driver_tag(flush_rq);
running = &fq->flush_queue[fq->flush_running_idx];
BUG_ON(fq->flush_pending_idx == fq->flush_running_idx);
@@ -320,14 +315,7 @@ static void blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq,
flush_rq->mq_ctx = first_rq->mq_ctx;
flush_rq->mq_hctx = first_rq->mq_hctx;
- if (!q->elevator) {
- fq->orig_rq = first_rq;
- flush_rq->tag = first_rq->tag;
- blk_mq_tag_set_rq(flush_rq->mq_hctx, first_rq->tag, flush_rq);
- } else {
- flush_rq->internal_tag = first_rq->internal_tag;
- }
-
+ flush_rq->internal_tag = first_rq->internal_tag;
flush_rq->cmd_flags = REQ_OP_FLUSH | REQ_PREFLUSH;
flush_rq->cmd_flags |= (flags & REQ_DRV) | (flags & REQ_FAILFAST_MASK);
flush_rq->rq_flags |= RQF_FLUSH_SEQ;
@@ -276,18 +276,8 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
struct request *rq = tags->static_rqs[tag];
req_flags_t rq_flags = 0;
- if (data->flags & BLK_MQ_REQ_INTERNAL) {
- rq->tag = -1;
- rq->internal_tag = tag;
- } else {
- if (data->hctx->flags & BLK_MQ_F_TAG_SHARED) {
- rq_flags = RQF_MQ_INFLIGHT;
- atomic_inc(&data->hctx->nr_active);
- }
- rq->tag = tag;
- rq->internal_tag = -1;
- data->hctx->tags->rqs[rq->tag] = rq;
- }
+ rq->internal_tag = tag;
+ rq->tag = -1;
/* csd/requeue_work/fifo_time is initialized before use */
rq->q = data->q;
@@ -472,14 +462,18 @@ static void __blk_mq_free_request(struct request *rq)
struct request_queue *q = rq->q;
struct blk_mq_ctx *ctx = rq->mq_ctx;
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
- const int sched_tag = rq->internal_tag;
+ const int tag = rq->internal_tag;
+ bool has_sched = !!hctx->sched_tags;
blk_pm_mark_last_busy(rq);
rq->mq_hctx = NULL;
- if (rq->tag != -1)
+ if (!has_sched)
+ blk_mq_put_tag(hctx->tags, ctx, tag);
+ else if (rq->tag >= 0)
blk_mq_put_tag(hctx->tags, ctx, rq->tag);
- if (sched_tag != -1)
- blk_mq_put_tag(hctx->sched_tags, ctx, sched_tag);
+
+ if (has_sched)
+ blk_mq_put_tag(hctx->sched_tags, ctx, tag);
blk_mq_sched_restart(hctx);
blk_queue_exit(q);
}
@@ -527,7 +521,7 @@ inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
blk_stat_add(rq, now);
}
- if (rq->internal_tag != -1)
+ if (rq->q->elevator && rq->internal_tag != -1)
blk_mq_sched_completed_request(rq, now);
blk_account_io_done(rq, now);
@@ -1037,14 +1031,21 @@ bool blk_mq_get_driver_tag(struct request *rq)
};
bool shared;
- if (rq->tag != -1)
- return true;
+ if (rq->tag >= 0)
+ goto allocated;
+
+ if (!rq->q->elevator) {
+ rq->tag = rq->internal_tag;
+ goto allocated;
+ }
if (blk_mq_tag_is_reserved(data.hctx->sched_tags, rq->internal_tag))
data.flags |= BLK_MQ_REQ_RESERVED;
- shared = blk_mq_tag_busy(data.hctx);
rq->tag = blk_mq_get_tag(&data);
+
+allocated:
+ shared = blk_mq_tag_busy(data.hctx);
if (rq->tag >= 0) {
if (shared) {
rq->rq_flags |= RQF_MQ_INFLIGHT;
@@ -197,26 +197,25 @@ static inline bool blk_mq_get_dispatch_budget(struct blk_mq_hw_ctx *hctx)
return true;
}
-static inline void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx,
- struct request *rq)
+static inline void blk_mq_put_driver_tag(struct request *rq)
{
- blk_mq_put_tag(hctx->tags, rq->mq_ctx, rq->tag);
+ struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
+ int tag = rq->tag;
+
+ if (tag < 0)
+ return;
+
rq->tag = -1;
+ if (rq->q->elevator)
+ blk_mq_put_tag(hctx->tags, rq->mq_ctx, tag);
+
if (rq->rq_flags & RQF_MQ_INFLIGHT) {
rq->rq_flags &= ~RQF_MQ_INFLIGHT;
atomic_dec(&hctx->nr_active);
}
}
-static inline void blk_mq_put_driver_tag(struct request *rq)
-{
- if (rq->tag == -1 || rq->internal_tag == -1)
- return;
-
- __blk_mq_put_driver_tag(rq->mq_hctx, rq);
-}
-
static inline void blk_mq_clear_mq_map(struct blk_mq_queue_map *qmap)
{
int cpu;
@@ -25,11 +25,6 @@ struct blk_flush_queue {
struct list_head flush_data_in_flight;
struct request *flush_rq;
- /*
- * flush_rq shares tag with this rq, both can't be active
- * at the same time
- */
- struct request *orig_rq;
struct lock_class_key key;
spinlock_t mq_flush_lock;
};
Especially for none elevator, rq->tag is assigned after the request is allocated, so there isn't any way to figure out if one request is in being dispatched. Also the code path wrt. driver tag becomes a bit difference between none and io scheduler. When one hctx becomes inactive, we have to prevent any request from being dispatched to LLD. And get driver tag provides one perfect chance to do that. Meantime we can drain any such requests by checking if rq->tag is assigned. So only assign rq->tag until blk_mq_get_driver_tag() is called. This way also simplifies code of dealing with driver tag a lot. Cc: Bart Van Assche <bvanassche@acm.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Garry <john.garry@huawei.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/blk-flush.c | 18 +++--------------- block/blk-mq.c | 41 +++++++++++++++++++++-------------------- block/blk-mq.h | 21 ++++++++++----------- block/blk.h | 5 ----- 4 files changed, 34 insertions(+), 51 deletions(-)