block: switch polling to be bio based

Replace the blk_poll interface that requires the caller to keep a queue
and cookie from the submissions with polling based on the bio.

Polling for the bio itself leads to a few advantages:

 - the cookie construction can made entirely private in blk-mq.c
 - the caller does not need to remember the request_queue and cookie
   separately and thus sidesteps their lifetime issues
 - keeping the device and the cookie inside the bio allows to trivially
   support polling BIOs remapping by stacking drivers
 - a lot of code to propagate the cookie back up the submission path can
   be removed entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2021-10-12 13:12:24 +02:00 committed by Jens Axboe
parent 19416123ab
commit 3e08773c38
39 changed files with 232 additions and 264 deletions

View file

@ -25,6 +25,7 @@ struct request;
struct sg_io_hdr;
struct blkcg_gq;
struct blk_flush_queue;
struct kiocb;
struct pr_ops;
struct rq_qos;
struct blk_queue_stats;
@ -550,7 +551,7 @@ static inline unsigned int blk_queue_depth(struct request_queue *q)
extern int blk_register_queue(struct gendisk *disk);
extern void blk_unregister_queue(struct gendisk *disk);
blk_qc_t submit_bio_noacct(struct bio *bio);
void submit_bio_noacct(struct bio *bio);
extern int blk_lld_busy(struct request_queue *q);
extern void blk_queue_split(struct bio **);
@ -568,7 +569,8 @@ blk_status_t errno_to_blk_status(int errno);
#define BLK_POLL_ONESHOT (1 << 0)
/* do not sleep to wait for the expected completion time */
#define BLK_POLL_NOSLEEP (1 << 1)
int blk_poll(struct request_queue *q, blk_qc_t cookie, unsigned int flags);
int bio_poll(struct bio *bio, unsigned int flags);
int iocb_bio_iopoll(struct kiocb *kiocb, unsigned int flags);
static inline struct request_queue *bdev_get_queue(struct block_device *bdev)
{
@ -1176,7 +1178,7 @@ static inline void blk_ksm_unregister(struct request_queue *q) { }
struct block_device_operations {
blk_qc_t (*submit_bio) (struct bio *bio);
void (*submit_bio)(struct bio *bio);
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);