blk-mq: support partial I/O completions

Add a new blk_mq_end_io_partial function to partially complete requests
as needed by the SCSI layer.  We do this by reusing blk_update_request
to advance the bio instead of having a simplified version of it in
the blk-mq code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Christoph Hellwig 2014-02-20 15:32:38 -08:00 committed by Jens Axboe
parent feb71dae1f
commit d6a25b3131
2 changed files with 12 additions and 33 deletions

View File

@ -283,38 +283,10 @@ void blk_mq_free_request(struct request *rq)
__blk_mq_free_request(hctx, ctx, rq);
}
static void blk_mq_bio_endio(struct request *rq, struct bio *bio, int error)
bool blk_mq_end_io_partial(struct request *rq, int error, unsigned int nr_bytes)
{
if (error)
clear_bit(BIO_UPTODATE, &bio->bi_flags);
else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
error = -EIO;
if (unlikely(rq->cmd_flags & REQ_QUIET))
set_bit(BIO_QUIET, &bio->bi_flags);
/* don't actually finish bio if it's part of flush sequence */
if (!(rq->cmd_flags & REQ_FLUSH_SEQ))
bio_endio(bio, error);
}
void blk_mq_end_io(struct request *rq, int error)
{
struct bio *bio = rq->bio;
unsigned int bytes = 0;
trace_block_rq_complete(rq->q, rq);
while (bio) {
struct bio *next = bio->bi_next;
bio->bi_next = NULL;
bytes += bio->bi_iter.bi_size;
blk_mq_bio_endio(rq, bio, error);
bio = next;
}
blk_account_io_completion(rq, bytes);
if (blk_update_request(rq, error, blk_rq_bytes(rq)))
return true;
blk_account_io_done(rq);
@ -322,8 +294,9 @@ void blk_mq_end_io(struct request *rq, int error)
rq->end_io(rq, error);
else
blk_mq_free_request(rq);
return false;
}
EXPORT_SYMBOL(blk_mq_end_io);
EXPORT_SYMBOL(blk_mq_end_io_partial);
static void __blk_mq_complete_request_remote(void *data)
{

View File

@ -133,7 +133,13 @@ struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *, const int ctx_ind
struct blk_mq_hw_ctx *blk_mq_alloc_single_hw_queue(struct blk_mq_reg *, unsigned int);
void blk_mq_free_single_hw_queue(struct blk_mq_hw_ctx *, unsigned int);
void blk_mq_end_io(struct request *rq, int error);
bool blk_mq_end_io_partial(struct request *rq, int error,
unsigned int nr_bytes);
static inline void blk_mq_end_io(struct request *rq, int error)
{
bool done = !blk_mq_end_io_partial(rq, error, blk_rq_bytes(rq));
BUG_ON(!done);
}
void blk_mq_complete_request(struct request *rq);