summaryrefslogtreecommitdiff
path: root/block
diff options
context:
space:
mode:
authorJens Axboe <axboe@kernel.dk>2020-07-01 22:58:32 -0600
committerJens Axboe <axboe@kernel.dk>2020-07-01 22:58:32 -0600
commit4e2f62e566b5bddec00682f36a404e05a3b64b6a (patch)
tree25a8ce0db9465f8c3f9e3f78b0098b54ab9cc636 /block
parentb53ac8b89157b5ff5d46c07eaa8b12e9d4e63b34 (diff)
downloadlwn-4e2f62e566b5bddec00682f36a404e05a3b64b6a.tar.gz
lwn-4e2f62e566b5bddec00682f36a404e05a3b64b6a.zip
Revert "blk-mq: put driver tag when this request is completed"
This reverts commits the following commits: 37f4a24c2469a10a4c16c641671bd766e276cf9f 723bf178f158abd1ce6069cb049581b3cb003aab 36a3df5a4574d5ddf59804fcd0c4e9654c514d9a The last one is the culprit, but we have to go a bit deeper to get this to revert cleanly. There's been a report that this breaks some MMC setups [1], and also causes an issue with swap [2]. Until this can be figured out, revert the offending commits. [1] https://lore.kernel.org/linux-block/57fb09b1-54ba-f3aa-f82c-d709b0e6b281@samsung.com/ [2] https://lore.kernel.org/linux-block/20200702043721.GA1087@lca.pw/ Reported-by: Marek Szyprowski <m.szyprowski@samsung.com> Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-flush.c23
-rw-r--r--block/blk-mq-tag.h12
-rw-r--r--block/blk-mq.c52
-rw-r--r--block/blk-mq.h20
-rw-r--r--block/blk.h5
5 files changed, 70 insertions, 42 deletions
diff --git a/block/blk-flush.c b/block/blk-flush.c
index e756db088d84..15ae0155ec07 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -236,10 +236,13 @@ 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)
- flush_rq->tag = BLK_MQ_NO_TAG;
- else
- flush_rq->internal_tag = BLK_MQ_NO_TAG;
+ 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;
+ }
running = &fq->flush_queue[fq->flush_running_idx];
BUG_ON(fq->flush_pending_idx == fq->flush_running_idx);
@@ -313,10 +316,13 @@ 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)
+ if (!q->elevator) {
+ fq->orig_rq = first_rq;
flush_rq->tag = first_rq->tag;
- else
+ 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->cmd_flags = REQ_OP_FLUSH | REQ_PREFLUSH;
flush_rq->cmd_flags |= (flags & REQ_DRV) | (flags & REQ_FAILFAST_MASK);
@@ -335,6 +341,11 @@ static void mq_flush_data_end_io(struct request *rq, blk_status_t error)
unsigned long flags;
struct blk_flush_queue *fq = blk_get_flush_queue(q, ctx);
+ if (q->elevator) {
+ WARN_ON(rq->tag < 0);
+ blk_mq_put_driver_tag(rq);
+ }
+
/*
* After populating an empty queue, kick it to avoid stall. Read
* the comment in flush_end_io().
diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h
index b1acac518c4e..3945c7f5b944 100644
--- a/block/blk-mq-tag.h
+++ b/block/blk-mq-tag.h
@@ -101,6 +101,18 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
return atomic_read(&hctx->nr_active) < depth;
}
+/*
+ * This helper should only be used for flush request to share tag
+ * with the request cloned from, and both the two requests can't be
+ * in flight at the same time. The caller has to make sure the tag
+ * can't be freed.
+ */
+static inline void blk_mq_tag_set_rq(struct blk_mq_hw_ctx *hctx,
+ unsigned int tag, struct request *rq)
+{
+ hctx->tags->rqs[tag] = rq;
+}
+
static inline bool blk_mq_tag_is_reserved(struct blk_mq_tags *tags,
unsigned int tag)
{
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 948987e9b6ab..abcf590f6238 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -277,20 +277,26 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
{
struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
struct request *rq = tags->static_rqs[tag];
+ req_flags_t rq_flags = 0;
if (data->q->elevator) {
rq->tag = BLK_MQ_NO_TAG;
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 = BLK_MQ_NO_TAG;
+ data->hctx->tags->rqs[rq->tag] = rq;
}
/* csd/requeue_work/fifo_time is initialized before use */
rq->q = data->q;
rq->mq_ctx = data->ctx;
rq->mq_hctx = data->hctx;
- rq->rq_flags = 0;
+ rq->rq_flags = rq_flags;
rq->cmd_flags = data->cmd_flags;
if (data->flags & BLK_MQ_REQ_PREEMPT)
rq->rq_flags |= RQF_PREEMPT;
@@ -660,32 +666,10 @@ static inline bool blk_mq_complete_need_ipi(struct request *rq)
return cpu_online(rq->mq_ctx->cpu);
}
-static void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx,
- struct request *rq)
-{
- blk_mq_put_tag(hctx->tags, rq->mq_ctx, rq->tag);
- rq->tag = BLK_MQ_NO_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 == BLK_MQ_NO_TAG || rq->internal_tag == BLK_MQ_NO_TAG)
- return;
-
- __blk_mq_put_driver_tag(rq->mq_hctx, rq);
-}
-
bool blk_mq_complete_request_remote(struct request *rq)
{
WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
- blk_mq_put_driver_tag(rq);
-
/*
* For a polled request, always complete locallly, it's pointless
* to redirect the completion.
@@ -1121,10 +1105,9 @@ static bool __blk_mq_get_driver_tag(struct request *rq)
{
struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags;
unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags;
+ bool shared = blk_mq_tag_busy(rq->mq_hctx);
int tag;
- blk_mq_tag_busy(rq->mq_hctx);
-
if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) {
bt = &rq->mq_hctx->tags->breserved_tags;
tag_offset = 0;
@@ -1137,22 +1120,19 @@ static bool __blk_mq_get_driver_tag(struct request *rq)
return false;
rq->tag = tag + tag_offset;
+ if (shared) {
+ rq->rq_flags |= RQF_MQ_INFLIGHT;
+ atomic_inc(&rq->mq_hctx->nr_active);
+ }
+ rq->mq_hctx->tags->rqs[rq->tag] = rq;
return true;
}
static bool blk_mq_get_driver_tag(struct request *rq)
{
- struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
-
- if (rq->tag == BLK_MQ_NO_TAG && !__blk_mq_get_driver_tag(rq))
- return false;
-
- if (hctx->flags & BLK_MQ_F_TAG_SHARED) {
- rq->rq_flags |= RQF_MQ_INFLIGHT;
- atomic_inc(&hctx->nr_active);
- }
- hctx->tags->rqs[rq->tag] = rq;
- return true;
+ if (rq->tag != BLK_MQ_NO_TAG)
+ return true;
+ return __blk_mq_get_driver_tag(rq);
}
static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 3661e821d460..863a2f3346d4 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -193,6 +193,26 @@ static inline bool blk_mq_get_dispatch_budget(struct request_queue *q)
return true;
}
+static inline void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx,
+ struct request *rq)
+{
+ blk_mq_put_tag(hctx->tags, rq->mq_ctx, rq->tag);
+ rq->tag = BLK_MQ_NO_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 == BLK_MQ_NO_TAG || rq->internal_tag == BLK_MQ_NO_TAG)
+ 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;
diff --git a/block/blk.h b/block/blk.h
index 9dcf51c94096..94f7c084f68f 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -25,6 +25,11 @@ 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;
};