From 54a88eb838d37af930c9f19e1930a4fba6789cb5 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Sat, 23 Oct 2021 17:21:32 +0100 Subject: [PATCH] block: add single bio async direct IO helper As with __blkdev_direct_IO_simple(), we can implement direct IO more efficiently if there is only one bio. Add __blkdev_direct_IO_async() and blkdev_bio_end_io_async(). This patch brings me from 4.45-4.5 MIOPS with nullblk to 4.7+. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/f0ae4109b7a6934adede490f84d188d53b97051b.1635006010.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- block/fops.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 84 insertions(+), 3 deletions(-) diff --git a/block/fops.c b/block/fops.c index 396537598e3e..a7b328296912 100644 --- a/block/fops.c +++ b/block/fops.c @@ -305,6 +305,85 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, return ret; } +static void blkdev_bio_end_io_async(struct bio *bio) +{ + struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio); + struct kiocb *iocb = dio->iocb; + ssize_t ret; + + if (likely(!bio->bi_status)) { + ret = dio->size; + iocb->ki_pos += ret; + } else { + ret = blk_status_to_errno(bio->bi_status); + } + + iocb->ki_complete(iocb, ret, 0); + + if (dio->flags & DIO_SHOULD_DIRTY) { + bio_check_pages_dirty(bio); + } else { + bio_release_pages(bio, false); + bio_put(bio); + } +} + +static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, + struct iov_iter *iter, + unsigned int nr_pages) +{ + struct block_device *bdev = iocb->ki_filp->private_data; + struct blkdev_dio *dio; + struct bio *bio; + loff_t pos = iocb->ki_pos; + int ret = 0; + + if ((pos | iov_iter_alignment(iter)) & + (bdev_logical_block_size(bdev) - 1)) + return -EINVAL; + + bio = bio_alloc_kiocb(iocb, nr_pages, &blkdev_dio_pool); + dio = container_of(bio, struct blkdev_dio, bio); + dio->flags = 0; + dio->iocb = iocb; + bio_set_dev(bio, bdev); + bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; + bio->bi_write_hint = iocb->ki_hint; + bio->bi_end_io = blkdev_bio_end_io_async; + bio->bi_ioprio = iocb->ki_ioprio; + + ret = bio_iov_iter_get_pages(bio, iter); + if (unlikely(ret)) { + bio->bi_status = BLK_STS_IOERR; + bio_endio(bio); + return ret; + } + dio->size = bio->bi_iter.bi_size; + + if (iov_iter_rw(iter) == READ) { + bio->bi_opf = REQ_OP_READ; + if (iter_is_iovec(iter)) { + dio->flags |= DIO_SHOULD_DIRTY; + bio_set_pages_dirty(bio); + } + } else { + bio->bi_opf = dio_bio_write_op(iocb); + task_io_account_write(bio->bi_iter.bi_size); + } + + if (iocb->ki_flags & IOCB_NOWAIT) + bio->bi_opf |= REQ_NOWAIT; + + if (iocb->ki_flags & IOCB_HIPRI) { + bio_set_polled(bio, iocb); + submit_bio(bio); + WRITE_ONCE(iocb->private, bio); + } else { + submit_bio(bio); + } + return -EIOCBQUEUED; +} + static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) { unsigned int nr_pages; @@ -313,9 +392,11 @@ static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) return 0; nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1); - if (is_sync_kiocb(iocb) && nr_pages <= BIO_MAX_VECS) - return __blkdev_direct_IO_simple(iocb, iter, nr_pages); - + if (likely(nr_pages <= BIO_MAX_VECS)) { + if (is_sync_kiocb(iocb)) + return __blkdev_direct_IO_simple(iocb, iter, nr_pages); + return __blkdev_direct_IO_async(iocb, iter, nr_pages); + } return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages)); }