[PATCH V2 5/8] block: tracking request allocation with q_usage_counter

Ming Lei
2017-09-01T18:49:55Z

This usage is basically same with blk-mq, so that we can
support to freeze queue easily.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/blk-core.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/block/blk-core.c b/block/blk-core.c
index ce2d3b6f6c62..85b15833a7a5 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1405,16 +1405,21 @@ static struct request *blk_old_get_request(struct request_queue *q,
unsigned int op, gfp_t gfp_mask)
{
struct request *rq;
+ int ret = 0;

WARN_ON_ONCE(q->mq_ops);

/* create ioc upfront */
create_io_context(gfp_mask, q->node);

+ ret = blk_queue_enter(q, !(gfp_mask & __GFP_DIRECT_RECLAIM));
+ if (ret)
+ return ERR_PTR(ret);
spin_lock_irq(q->queue_lock);
rq = get_request(q, op, NULL, gfp_mask);
if (IS_ERR(rq)) {
spin_unlock_irq(q->queue_lock);
+ blk_queue_exit(q);
return rq;
}

@@ -1586,6 +1591,7 @@ void __blk_put_request(struct request_queue *q, struct request *req)
blk_free_request(rl, req);
freed_request(rl, sync, rq_flags);
blk_put_rl(rl);
+ blk_queue_exit(q);
}
}
EXPORT_SYMBOL_GPL(__blk_put_request);
@@ -1867,8 +1873,10 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
* Grab a free request. This is might sleep but can not fail.
* Returns with the queue unlocked.
*/
+ blk_queue_enter_live(q);
req = get_request(q, bio->bi_opf, bio, GFP_NOIO);
if (IS_ERR(req)) {
+ blk_queue_exit(q);
__wbt_done(q->rq_wb, wb_acct);
if (PTR_ERR(req) == -ENOMEM)
bio->bi_status = BLK_STS_RESOURCE;
--
2.9.5