A side effect of this patch is that the GFP mask that is passed to
several allocation functions in the legacy block layer is changed
from GFP_KERNEL into __GFP_DIRECT_RECLAIM.
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Ming Lei <ming.lei@xxxxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Johannes Thumshirn <jthumshirn@xxxxxxx>
---
block/blk-core.c | 50 +++++++++++++++++++++++++++++++++++---------------
include/linux/blkdev.h | 3 +++
2 files changed, 38 insertions(+), 15 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 265a69511c47..03156d9ede94 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1157,7 +1157,7 @@ int blk_update_nr_requests(struct request_queue *q, unsigned int nr)
* @rl: request list to allocate from
* @op: operation and flags
* @bio: bio to allocate request for (can be %NULL)
- * @gfp_mask: allocation mask
+ * @flags: BLQ_MQ_REQ_* flags
*
* Get a free request from @q. This function may fail under memory
* pressure or if @q is dead.
@@ -1167,7 +1167,7 @@ int blk_update_nr_requests(struct request_queue *q, unsigned int nr)
* Returns request pointer on success, with @q->queue_lock *not held*.
*/
static struct request *__get_request(struct request_list *rl, unsigned int op,
- struct bio *bio, gfp_t gfp_mask)
+ struct bio *bio, unsigned int flags)
{
struct request_queue *q = rl->q;
struct request *rq;
@@ -1176,6 +1176,8 @@ static struct request *__get_request(struct request_list *rl, unsigned int op,
struct io_cq *icq = NULL;
const bool is_sync = op_is_sync(op);
int may_queue;
+ gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC :
+ __GFP_DIRECT_RECLAIM;
req_flags_t rq_flags = RQF_ALLOCED;
lockdep_assert_held(q->queue_lock);
@@ -1336,7 +1338,7 @@ static struct request *__get_request(struct request_list *rl, unsigned int op,
* @q: request_queue to allocate request from
* @op: operation and flags
* @bio: bio to allocate request for (can be %NULL)
- * @gfp_mask: allocation mask
+ * @flags: BLK_MQ_REQ_* flags.
*
* Get a free request from @q. If %__GFP_DIRECT_RECLAIM is set in @gfp_mask,
* this function keeps retrying under memory pressure and fails iff @q is dead.
@@ -1346,7 +1348,7 @@ static struct request *__get_request(struct request_list *rl, unsigned int op,
* Returns request pointer on success, with @q->queue_lock *not held*.
*/
static struct request *get_request(struct request_queue *q, unsigned int op,
- struct bio *bio, gfp_t gfp_mask)
+ struct bio *bio, unsigned int flags)
{
const bool is_sync = op_is_sync(op);
DEFINE_WAIT(wait);
@@ -1358,7 +1360,7 @@ static struct request *get_request(struct request_queue *q, unsigned int op,
rl = blk_get_rl(q, bio); /* transferred to @rq on success */
retry:
- rq = __get_request(rl, op, bio, gfp_mask);
+ rq = __get_request(rl, op, bio, flags);
if (!IS_ERR(rq))
return rq;
@@ -1367,7 +1369,7 @@ static struct request *get_request(struct request_queue *q, unsigned int op,
return ERR_PTR(-EAGAIN);
}
- if (!gfpflags_allow_blocking(gfp_mask) || unlikely(blk_queue_dying(q))) {
+ if ((flags & BLK_MQ_REQ_NOWAIT) || unlikely(blk_queue_dying(q))) {
blk_put_rl(rl);
return rq;
}
@@ -1394,10 +1396,13 @@ static struct request *get_request(struct request_queue *q, unsigned int op,
goto retry;
}
+/* flags: BLK_MQ_REQ_PREEMPT and/or BLK_MQ_REQ_NOWAIT. */
static struct request *blk_old_get_request(struct request_queue *q,
- unsigned int op, gfp_t gfp_mask)
+ unsigned int op, unsigned int flags)
{
struct request *rq;
+ gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC :
+ __GFP_DIRECT_RECLAIM;
int ret = 0;
WARN_ON_ONCE(q->mq_ops);
@@ -1410,7 +1415,7 @@ static struct request *blk_old_get_request(struct request_queue *q,
if (ret)
return ERR_PTR(ret);
spin_lock_irq(q->queue_lock);
- rq = get_request(q, op, NULL, gfp_mask);
+ rq = get_request(q, op, NULL, flags);
if (IS_ERR(rq)) {
spin_unlock_irq(q->queue_lock);
blk_queue_exit(q);
@@ -1424,25 +1429,40 @@ static struct request *blk_old_get_request(struct request_queue *q,
return rq;
}
-struct request *blk_get_request(struct request_queue *q, unsigned int op,
- gfp_t gfp_mask)
+/**
+ * blk_get_request_flags - allocate a request
+ * @q: request queue to allocate a request for
+ * @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC.
+ * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT.
+ */
+struct request *blk_get_request_flags(struct request_queue *q, unsigned int op,
+ unsigned int flags)
{
struct request *req;
+ WARN_ON_ONCE(op & REQ_NOWAIT);
+ WARN_ON_ONCE(flags & ~BLK_MQ_REQ_NOWAIT);
+
if (q->mq_ops) {
- req = blk_mq_alloc_request(q, op,
- (gfp_mask & __GFP_DIRECT_RECLAIM) ?
- 0 : BLK_MQ_REQ_NOWAIT);
+ req = blk_mq_alloc_request(q, op, flags);
if (!IS_ERR(req) && q->mq_ops->initialize_rq_fn)
q->mq_ops->initialize_rq_fn(req);
} else {
- req = blk_old_get_request(q, op, gfp_mask);
+ req = blk_old_get_request(q, op, flags);
if (!IS_ERR(req) && q->initialize_rq_fn)
q->initialize_rq_fn(req);
}
return req;
}
+EXPORT_SYMBOL(blk_get_request_flags);
+
+struct request *blk_get_request(struct request_queue *q, unsigned int op,
+ gfp_t gfp_mask)
+{
+ return blk_get_request_flags(q, op, gfp_mask & __GFP_DIRECT_RECLAIM ?
+ 0 : BLK_MQ_REQ_NOWAIT);
+}
EXPORT_SYMBOL(blk_get_request);
/**
@@ -1868,7 +1888,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
* Returns with the queue unlocked.
*/
blk_queue_enter_live(q);
- req = get_request(q, bio->bi_opf, bio, GFP_NOIO);
+ req = get_request(q, bio->bi_opf, bio, 0);
if (IS_ERR(req)) {
blk_queue_exit(q);
__wbt_done(q->rq_wb, wb_acct);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 9fb71fc7d0e8..3f7b08a9b9ae 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -935,6 +935,9 @@ extern void blk_rq_init(struct request_queue *q, struct request *rq);
extern void blk_init_request_from_bio(struct request *req, struct bio *bio);
extern void blk_put_request(struct request *);
extern void __blk_put_request(struct request_queue *, struct request *);
+extern struct request *blk_get_request_flags(struct request_queue *,
+ unsigned int op,
+ unsigned int flags);
extern struct request *blk_get_request(struct request_queue *, unsigned int op,
gfp_t gfp_mask);
extern void blk_requeue_request(struct request_queue *, struct request *);
--
2.14.2
