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 <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-mq.c b/block/blk-mq.c
index b9230c5..43eb315 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -210,24 +210,23 @@
}
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 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 @@
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 @@
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 @@
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++;