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block: add ->poll_bio to block_device_operations 

Prepare for supporting IO polling for bio-based driver.

Add ->poll_bio callback so that bio-based driver can provide their own
logic for polling bio.

Also fix ->submit_bio_bio typo in comment block above
__submit_bio_noacct.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Ming Lei 2022-03-04 21:08:03 -05:00 committed by Mike Snitzer
parent 168678d765
commit 69fe0f2989
3 changed files with 15 additions and 5 deletions
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14
block/blk-core.c
View File

@ -708,7 +708,7 @@ static void __submit_bio(struct bio *bio)
*
* bio_list_on_stack[0] contains bios submitted by the current ->submit_bio.
* bio_list_on_stack[1] contains bios that were submitted before the current
* ->submit_bio_bio, but that haven't been processed yet.
* ->submit_bio, but that haven't been processed yet.
*/
static void __submit_bio_noacct(struct bio *bio)
{
@ -975,7 +975,7 @@ int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags)
{
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
blk_qc_t cookie = READ_ONCE(bio->bi_cookie);
int ret;
int ret = 0;
if (cookie == BLK_QC_T_NONE ||
!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
@ -985,10 +985,14 @@ int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags)
if (blk_queue_enter(q, BLK_MQ_REQ_NOWAIT))
return 0;
if (WARN_ON_ONCE(!queue_is_mq(q)))
ret = 0; /* not yet implemented, should not happen */
else
if (queue_is_mq(q)) {
ret = blk_mq_poll(q, cookie, iob, flags);
} else {
struct gendisk *disk = q->disk;
if (disk && disk->fops->poll_bio)
ret = disk->fops->poll_bio(bio, iob, flags);
}
blk_queue_exit(q);
return ret;
}

4
block/genhd.c
View File

@ -410,6 +410,10 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
struct device *ddev = disk_to_dev(disk);
int ret;
/* Only makes sense for bio-based to set ->poll_bio */
if (queue_is_mq(disk->queue) && disk->fops->poll_bio)
return -EINVAL;
/*
* The disk queue should now be all set with enough information about
* the device for the elevator code to pick an adequate default

2
include/linux/blkdev.h
View File

@ -1455,6 +1455,8 @@ enum blk_unique_id {
struct block_device_operations {
void (*submit_bio)(struct bio *bio);
int (*poll_bio)(struct bio *bio, struct io_comp_batch *iob,
unsigned int flags);
int (*open) (struct block_device *, fmode_t);
void (*release) (struct gendisk *, fmode_t);
int (*rw_page)(struct block_device *, sector_t, struct page *, unsigned int);