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authorLinus Torvalds <torvalds@linux-foundation.org>2015-11-10 17:23:49 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-10 17:23:49 -0800
commit3419b45039c6b799c974a8019361c045e7ca232c (patch)
tree36a63602036cc50f34fadcbd5d5d8fca94e44297 /block/blk-core.c
parent01504f5e9e071f1dde1062e3be15f54d4555308f (diff)
parentc1c534609fe8a859f9c8108a5591e6e8a97e34d1 (diff)
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Merge branch 'for-4.4/io-poll' of git://git.kernel.dk/linux-block
Pull block IO poll support from Jens Axboe: "Various groups have been doing experimentation around IO polling for (really) fast devices. The code has been reviewed and has been sitting on the side for a few releases, but this is now good enough for coordinated benchmarking and further experimentation. Currently O_DIRECT sync read/write are supported. A framework is in the works that allows scalable stats tracking so we can auto-tune this. And we'll add libaio support as well soon. Fow now, it's an opt-in feature for test purposes" * 'for-4.4/io-poll' of git://git.kernel.dk/linux-block: direct-io: be sure to assign dio->bio_bdev for both paths directio: add block polling support NVMe: add blk polling support block: add block polling support blk-mq: return tag/queue combo in the make_request_fn handlers block: change ->make_request_fn() and users to return a queue cookie
Diffstat (limited to 'block/blk-core.c')
-rw-r--r--block/blk-core.c67
1 files changed, 57 insertions, 10 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 590cca21c24a..2bbf08cd2900 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -809,7 +809,7 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
}
EXPORT_SYMBOL(blk_init_queue_node);
-static void blk_queue_bio(struct request_queue *q, struct bio *bio);
+static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio);
struct request_queue *
blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
@@ -1678,7 +1678,7 @@ void init_request_from_bio(struct request *req, struct bio *bio)
blk_rq_bio_prep(req->q, req, bio);
}
-static void blk_queue_bio(struct request_queue *q, struct bio *bio)
+static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
{
const bool sync = !!(bio->bi_rw & REQ_SYNC);
struct blk_plug *plug;
@@ -1698,7 +1698,7 @@ static void blk_queue_bio(struct request_queue *q, struct bio *bio)
if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
bio->bi_error = -EIO;
bio_endio(bio);
- return;
+ return BLK_QC_T_NONE;
}
if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
@@ -1713,7 +1713,7 @@ static void blk_queue_bio(struct request_queue *q, struct bio *bio)
*/
if (!blk_queue_nomerges(q)) {
if (blk_attempt_plug_merge(q, bio, &request_count, NULL))
- return;
+ return BLK_QC_T_NONE;
} else
request_count = blk_plug_queued_count(q);
@@ -1791,6 +1791,8 @@ get_rq:
out_unlock:
spin_unlock_irq(q->queue_lock);
}
+
+ return BLK_QC_T_NONE;
}
/*
@@ -1996,12 +1998,13 @@ end_io:
* a lower device by calling into generic_make_request recursively, which
* means the bio should NOT be touched after the call to ->make_request_fn.
*/
-void generic_make_request(struct bio *bio)
+blk_qc_t generic_make_request(struct bio *bio)
{
struct bio_list bio_list_on_stack;
+ blk_qc_t ret = BLK_QC_T_NONE;
if (!generic_make_request_checks(bio))
- return;
+ goto out;
/*
* We only want one ->make_request_fn to be active at a time, else
@@ -2015,7 +2018,7 @@ void generic_make_request(struct bio *bio)
*/
if (current->bio_list) {
bio_list_add(current->bio_list, bio);
- return;
+ goto out;
}
/* following loop may be a bit non-obvious, and so deserves some
@@ -2040,7 +2043,7 @@ void generic_make_request(struct bio *bio)
if (likely(blk_queue_enter(q, __GFP_DIRECT_RECLAIM) == 0)) {
- q->make_request_fn(q, bio);
+ ret = q->make_request_fn(q, bio);
blk_queue_exit(q);
@@ -2053,6 +2056,9 @@ void generic_make_request(struct bio *bio)
}
} while (bio);
current->bio_list = NULL; /* deactivate */
+
+out:
+ return ret;
}
EXPORT_SYMBOL(generic_make_request);
@@ -2066,7 +2072,7 @@ EXPORT_SYMBOL(generic_make_request);
* interfaces; @bio must be presetup and ready for I/O.
*
*/
-void submit_bio(int rw, struct bio *bio)
+blk_qc_t submit_bio(int rw, struct bio *bio)
{
bio->bi_rw |= rw;
@@ -2100,7 +2106,7 @@ void submit_bio(int rw, struct bio *bio)
}
}
- generic_make_request(bio);
+ return generic_make_request(bio);
}
EXPORT_SYMBOL(submit_bio);
@@ -3306,6 +3312,47 @@ void blk_finish_plug(struct blk_plug *plug)
}
EXPORT_SYMBOL(blk_finish_plug);
+bool blk_poll(struct request_queue *q, blk_qc_t cookie)
+{
+ struct blk_plug *plug;
+ long state;
+
+ if (!q->mq_ops || !q->mq_ops->poll || !blk_qc_t_valid(cookie) ||
+ !test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
+ return false;
+
+ plug = current->plug;
+ if (plug)
+ blk_flush_plug_list(plug, false);
+
+ state = current->state;
+ while (!need_resched()) {
+ unsigned int queue_num = blk_qc_t_to_queue_num(cookie);
+ struct blk_mq_hw_ctx *hctx = q->queue_hw_ctx[queue_num];
+ int ret;
+
+ hctx->poll_invoked++;
+
+ ret = q->mq_ops->poll(hctx, blk_qc_t_to_tag(cookie));
+ if (ret > 0) {
+ hctx->poll_success++;
+ set_current_state(TASK_RUNNING);
+ return true;
+ }
+
+ if (signal_pending_state(state, current))
+ set_current_state(TASK_RUNNING);
+
+ if (current->state == TASK_RUNNING)
+ return true;
+ if (ret < 0)
+ break;
+ cpu_relax();
+ }
+
+ return false;
+}
+
#ifdef CONFIG_PM
/**
* blk_pm_runtime_init - Block layer runtime PM initialization routine