This patch adds poll-by-default functionality back for 4.6 by adding a
queue flag which specifies that it should always try polling, rather
than only if the io specifies it.
Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>
---
block/blk-core.c | 8 ++++++++
fs/direct-io.c | 7 ++++++-
include/linux/blkdev.h | 2 ++
3 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 827f8ba..d85f913 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -3335,6 +3335,14 @@ void blk_finish_plug(struct blk_plug *plug)
}
EXPORT_SYMBOL(blk_finish_plug);
+bool blk_force_poll(struct request_queue *q)
+{
+ if (!q->mq_ops || !q->mq_ops->poll ||
+ !test_bit(QUEUE_FLAG_POLL_FORCE, &q->queue_flags))
+ return false;
+ return true;
+}
+
bool blk_poll(struct request_queue *q, blk_qc_t cookie)
{
struct blk_plug *plug;
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 476f1ec..2775552 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -450,7 +450,12 @@ static struct bio *dio_await_one(struct dio *dio)
__set_current_state(TASK_UNINTERRUPTIBLE);
dio->waiter = current;
spin_unlock_irqrestore(&dio->bio_lock, flags);
- if (!(dio->iocb->ki_flags & IOCB_HIPRI) ||
+ /*
+ * Polling must be enabled explicitly on a per-IO basis,
+ * or through the queue's sysfs io_poll_force control
+ */
+ if (!((dio->iocb->ki_flags & IOCB_HIPRI) ||
+ (blk_force_poll(bdev_get_queue(dio->bio_bdev)))) ||
!blk_poll(bdev_get_queue(dio->bio_bdev), dio->bio_cookie))
io_schedule();
/* wake up sets us TASK_RUNNING */
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 7e5d7e0..e87ef17 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -491,6 +491,7 @@ struct request_queue {
#define QUEUE_FLAG_INIT_DONE 20 /* queue is initialized */
#define QUEUE_FLAG_NO_SG_MERGE 21 /* don't attempt to merge SG segments*/
#define QUEUE_FLAG_POLL 22 /* IO polling enabled if set */
+#define QUEUE_FLAG_POLL_FORCE 23 /* IO polling forced if set */
#define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
(1 << QUEUE_FLAG_STACKABLE) | \
@@ -824,6 +825,7 @@ extern int blk_execute_rq(struct request_queue *, struct gendisk *,
extern void blk_execute_rq_nowait(struct request_queue *, struct gendisk *,
struct request *, int, rq_end_io_fn *);
+bool blk_force_poll(struct request_queue *q);
bool blk_poll(struct request_queue *q, blk_qc_t cookie);
static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
--
2.5.0
--
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