From: Ming Lei Date: Sat, 31 May 2014 16:43:37 +0000 (+0800) Subject: blk-mq: fix schedule from atomic context X-Git-Tag: firefly_0821_release~176^2~3785^2~19^2~5 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=cb96a42cc1f50ba1c7b1e9b2343bec80b926107f;p=firefly-linux-kernel-4.4.55.git blk-mq: fix schedule from atomic context blk_mq_put_ctx() has to be called before io_schedule() in bt_get(). This patch fixes the problem by taking similar approach from percpu_ida allocation for the situation. Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index d90c4aeb7dd3..1aab39f71d95 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -221,8 +221,10 @@ static struct bt_wait_state *bt_wait_ptr(struct blk_mq_bitmap_tags *bt, return bs; } -static int bt_get(struct blk_mq_bitmap_tags *bt, struct blk_mq_hw_ctx *hctx, - unsigned int *last_tag, gfp_t gfp) +static int bt_get(struct blk_mq_alloc_data *data, + struct blk_mq_bitmap_tags *bt, + struct blk_mq_hw_ctx *hctx, + unsigned int *last_tag) { struct bt_wait_state *bs; DEFINE_WAIT(wait); @@ -232,7 +234,7 @@ static int bt_get(struct blk_mq_bitmap_tags *bt, struct blk_mq_hw_ctx *hctx, if (tag != -1) return tag; - if (!(gfp & __GFP_WAIT)) + if (!(data->gfp & __GFP_WAIT)) return -1; bs = bt_wait_ptr(bt, hctx); @@ -249,50 +251,62 @@ static int bt_get(struct blk_mq_bitmap_tags *bt, struct blk_mq_hw_ctx *hctx, if (was_empty) atomic_set(&bs->wait_cnt, bt->wake_cnt); + blk_mq_put_ctx(data->ctx); + io_schedule(); + + data->ctx = blk_mq_get_ctx(data->q); + data->hctx = data->q->mq_ops->map_queue(data->q, + data->ctx->cpu); + if (data->reserved) { + bt = &data->hctx->tags->breserved_tags; + } else { + last_tag = &data->ctx->last_tag; + hctx = data->hctx; + bt = &hctx->tags->bitmap_tags; + } + finish_wait(&bs->wait, &wait); + bs = bt_wait_ptr(bt, hctx); } while (1); finish_wait(&bs->wait, &wait); return tag; } -static unsigned int __blk_mq_get_tag(struct blk_mq_tags *tags, - struct blk_mq_hw_ctx *hctx, - unsigned int *last_tag, gfp_t gfp) +static unsigned int __blk_mq_get_tag(struct blk_mq_alloc_data *data) { int tag; - tag = bt_get(&tags->bitmap_tags, hctx, last_tag, gfp); + tag = bt_get(data, &data->hctx->tags->bitmap_tags, data->hctx, + &data->ctx->last_tag); if (tag >= 0) - return tag + tags->nr_reserved_tags; + return tag + data->hctx->tags->nr_reserved_tags; return BLK_MQ_TAG_FAIL; } -static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_tags *tags, - gfp_t gfp) +static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_alloc_data *data) { int tag, zero = 0; - if (unlikely(!tags->nr_reserved_tags)) { + if (unlikely(!data->hctx->tags->nr_reserved_tags)) { WARN_ON_ONCE(1); return BLK_MQ_TAG_FAIL; } - tag = bt_get(&tags->breserved_tags, NULL, &zero, gfp); + tag = bt_get(data, &data->hctx->tags->breserved_tags, NULL, &zero); if (tag < 0) return BLK_MQ_TAG_FAIL; return tag; } -unsigned int blk_mq_get_tag(struct blk_mq_hw_ctx *hctx, unsigned int *last_tag, - gfp_t gfp, bool reserved) +unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data) { - if (!reserved) - return __blk_mq_get_tag(hctx->tags, hctx, last_tag, gfp); + if (!data->reserved) + return __blk_mq_get_tag(data); - return __blk_mq_get_reserved_tag(hctx->tags, gfp); + return __blk_mq_get_reserved_tag(data); } static struct bt_wait_state *bt_wake_ptr(struct blk_mq_bitmap_tags *bt) diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h index c959de58d2a5..98696a65d4d4 100644 --- a/block/blk-mq-tag.h +++ b/block/blk-mq-tag.h @@ -48,7 +48,7 @@ struct blk_mq_tags { extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int reserved_tags, int node); extern void blk_mq_free_tags(struct blk_mq_tags *tags); -extern unsigned int blk_mq_get_tag(struct blk_mq_hw_ctx *hctx, unsigned int *last_tag, gfp_t gfp, bool reserved); +extern unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data); extern void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag, unsigned int *last_tag); extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags); extern ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page); diff --git a/block/blk-mq.c b/block/blk-mq.c index b9230c522c6b..43eb3156e110 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -210,24 +210,23 @@ static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx, } static struct request * -__blk_mq_alloc_request(struct request_queue *q, struct blk_mq_hw_ctx *hctx, - struct blk_mq_ctx *ctx, int rw, gfp_t gfp, bool reserved) +__blk_mq_alloc_request(struct blk_mq_alloc_data *data, int rw) { struct request *rq; unsigned int tag; - tag = blk_mq_get_tag(hctx, &ctx->last_tag, gfp, reserved); + tag = blk_mq_get_tag(data); if (tag != BLK_MQ_TAG_FAIL) { - rq = hctx->tags->rqs[tag]; + rq = data->hctx->tags->rqs[tag]; rq->cmd_flags = 0; - if (blk_mq_tag_busy(hctx)) { + if (blk_mq_tag_busy(data->hctx)) { rq->cmd_flags = REQ_MQ_INFLIGHT; - atomic_inc(&hctx->nr_active); + atomic_inc(&data->hctx->nr_active); } rq->tag = tag; - blk_mq_rq_ctx_init(q, ctx, rq, rw); + blk_mq_rq_ctx_init(data->q, data->ctx, rq, rw); return rq; } @@ -240,22 +239,27 @@ struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp, struct blk_mq_ctx *ctx; struct blk_mq_hw_ctx *hctx; struct request *rq; + struct blk_mq_alloc_data alloc_data; if (blk_mq_queue_enter(q)) return NULL; ctx = blk_mq_get_ctx(q); hctx = q->mq_ops->map_queue(q, ctx->cpu); + blk_mq_set_alloc_data(&alloc_data, q, gfp & ~__GFP_WAIT, + reserved, ctx, hctx); - rq = __blk_mq_alloc_request(q, hctx, ctx, rw, gfp & ~__GFP_WAIT, - reserved); + rq = __blk_mq_alloc_request(&alloc_data, rw); if (!rq && (gfp & __GFP_WAIT)) { __blk_mq_run_hw_queue(hctx); blk_mq_put_ctx(ctx); ctx = blk_mq_get_ctx(q); hctx = q->mq_ops->map_queue(q, ctx->cpu); - rq = __blk_mq_alloc_request(q, hctx, ctx, rw, gfp, reserved); + blk_mq_set_alloc_data(&alloc_data, q, gfp, reserved, ctx, + hctx); + rq = __blk_mq_alloc_request(&alloc_data, rw); + ctx = alloc_data.ctx; } blk_mq_put_ctx(ctx); return rq; @@ -1136,6 +1140,7 @@ static struct request *blk_mq_map_request(struct request_queue *q, struct blk_mq_ctx *ctx; struct request *rq; int rw = bio_data_dir(bio); + struct blk_mq_alloc_data alloc_data; if (unlikely(blk_mq_queue_enter(q))) { bio_endio(bio, -EIO); @@ -1149,7 +1154,9 @@ static struct request *blk_mq_map_request(struct request_queue *q, rw |= REQ_SYNC; trace_block_getrq(q, bio, rw); - rq = __blk_mq_alloc_request(q, hctx, ctx, rw, GFP_ATOMIC, false); + blk_mq_set_alloc_data(&alloc_data, q, GFP_ATOMIC, false, ctx, + hctx); + rq = __blk_mq_alloc_request(&alloc_data, rw); if (unlikely(!rq)) { __blk_mq_run_hw_queue(hctx); blk_mq_put_ctx(ctx); @@ -1157,8 +1164,11 @@ static struct request *blk_mq_map_request(struct request_queue *q, ctx = blk_mq_get_ctx(q); hctx = q->mq_ops->map_queue(q, ctx->cpu); - rq = __blk_mq_alloc_request(q, hctx, ctx, rw, - __GFP_WAIT|GFP_ATOMIC, false); + blk_mq_set_alloc_data(&alloc_data, q, + __GFP_WAIT|GFP_ATOMIC, false, ctx, hctx); + rq = __blk_mq_alloc_request(&alloc_data, rw); + ctx = alloc_data.ctx; + hctx = alloc_data.hctx; } hctx->queued++; diff --git a/block/blk-mq.h b/block/blk-mq.h index 57a7968e47b3..26460884c6cd 100644 --- a/block/blk-mq.h +++ b/block/blk-mq.h @@ -91,4 +91,27 @@ static inline void blk_mq_put_ctx(struct blk_mq_ctx *ctx) put_cpu(); } +struct blk_mq_alloc_data { + /* input parameter */ + struct request_queue *q; + gfp_t gfp; + bool reserved; + + /* input & output parameter */ + struct blk_mq_ctx *ctx; + struct blk_mq_hw_ctx *hctx; +}; + +static inline void blk_mq_set_alloc_data(struct blk_mq_alloc_data *data, + struct request_queue *q, gfp_t gfp, bool reserved, + struct blk_mq_ctx *ctx, + struct blk_mq_hw_ctx *hctx) +{ + data->q = q; + data->gfp = gfp; + data->reserved = reserved; + data->ctx = ctx; + data->hctx = hctx; +} + #endif