From: Keith Busch Date: Wed, 27 Aug 2025 14:12:52 +0000 (-0700) Subject: block: add size alignment to bio_iov_iter_get_pages X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=743bf2e0c49c835cb7c4e4ac7d5a2610587047be;p=users%2Fhch%2Fmisc.git block: add size alignment to bio_iov_iter_get_pages The block layer tries to align bio vectors to the block device's logical block size. Some cases don't have a block device, or we may need to align to something larger, which we can't derive it from the queue limits. Have the caller specify what they want, or allow any length alignment if nothing was specified. Since the most common use case relies on the block device's limits, a helper function is provided. Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Signed-off-by: Jens Axboe --- diff --git a/block/bio.c b/block/bio.c index 971d96afaf8d..f91dc9f32bdc 100644 --- a/block/bio.c +++ b/block/bio.c @@ -1208,7 +1208,8 @@ static unsigned int get_contig_folio_len(unsigned int *num_pages, * For a multi-segment *iter, this function only adds pages from the next * non-empty segment of the iov iterator. */ -static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) +static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter, + unsigned len_align_mask) { iov_iter_extraction_t extraction_flags = 0; unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt; @@ -1217,7 +1218,7 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) struct page **pages = (struct page **)bv; ssize_t size; unsigned int num_pages, i = 0; - size_t offset, folio_offset, left, len; + size_t offset, folio_offset, left, len, trim; int ret = 0; /* @@ -1246,8 +1247,8 @@ static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE); - if (bio->bi_bdev) { - size_t trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1); + trim = size & len_align_mask; + if (trim) { iov_iter_revert(iter, trim); size -= trim; } @@ -1302,9 +1303,10 @@ out: } /** - * bio_iov_iter_get_pages - add user or kernel pages to a bio + * bio_iov_iter_get_pages_aligned - add user or kernel pages to a bio * @bio: bio to add pages to * @iter: iov iterator describing the region to be added + * @len_align_mask: the mask to align each vector size to, 0 for any length * * This takes either an iterator pointing to user memory, or one pointing to * kernel pages (BVEC iterator). If we're adding user pages, we pin them and @@ -1321,7 +1323,8 @@ out: * MM encounters an error pinning the requested pages, it stops. Error * is returned only if 0 pages could be pinned. */ -int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) +int bio_iov_iter_get_pages_aligned(struct bio *bio, struct iov_iter *iter, + unsigned len_align_mask) { int ret = 0; @@ -1337,12 +1340,12 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) if (iov_iter_extract_will_pin(iter)) bio_set_flag(bio, BIO_PAGE_PINNED); do { - ret = __bio_iov_iter_get_pages(bio, iter); + ret = __bio_iov_iter_get_pages(bio, iter, len_align_mask); } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0)); return bio->bi_vcnt ? 0 : ret; } -EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages); +EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages_aligned); static void submit_bio_wait_endio(struct bio *bio) { diff --git a/block/fops.c b/block/fops.c index 82451ac8ff25..d136fb5f6b6a 100644 --- a/block/fops.c +++ b/block/fops.c @@ -78,7 +78,7 @@ static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb, if (iocb->ki_flags & IOCB_ATOMIC) bio.bi_opf |= REQ_ATOMIC; - ret = bio_iov_iter_get_pages(&bio, iter); + ret = bio_iov_iter_get_bdev_pages(&bio, iter, bdev); if (unlikely(ret)) goto out; ret = bio.bi_iter.bi_size; @@ -212,7 +212,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, bio->bi_end_io = blkdev_bio_end_io; bio->bi_ioprio = iocb->ki_ioprio; - ret = bio_iov_iter_get_pages(bio, iter); + ret = bio_iov_iter_get_bdev_pages(bio, iter, bdev); if (unlikely(ret)) { bio->bi_status = BLK_STS_IOERR; bio_endio(bio); @@ -348,7 +348,7 @@ static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, */ bio_iov_bvec_set(bio, iter); } else { - ret = bio_iov_iter_get_pages(bio, iter); + ret = bio_iov_iter_get_bdev_pages(bio, iter, bdev); if (unlikely(ret)) goto out_bio_put; } diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index b84f6af2eb4c..fea23fa6a402 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -434,7 +434,7 @@ static int iomap_dio_bio_iter(struct iomap_iter *iter, struct iomap_dio *dio) bio->bi_private = dio; bio->bi_end_io = iomap_dio_bio_end_io; - ret = bio_iov_iter_get_pages(bio, dio->submit.iter); + ret = bio_iov_iter_get_bdev_pages(bio, dio->submit.iter, iomap->bdev); if (unlikely(ret)) { /* * We have to stop part way through an IO. We must fall diff --git a/include/linux/bio.h b/include/linux/bio.h index 13d1df02656a..a64a30131031 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -446,7 +446,14 @@ int submit_bio_wait(struct bio *bio); int bdev_rw_virt(struct block_device *bdev, sector_t sector, void *data, size_t len, enum req_op op); -int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter); +int bio_iov_iter_get_pages_aligned(struct bio *bio, struct iov_iter *iter, + unsigned len_align_mask); + +static inline int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) +{ + return bio_iov_iter_get_pages_aligned(bio, iter, 0); +} + void bio_iov_bvec_set(struct bio *bio, const struct iov_iter *iter); void __bio_release_pages(struct bio *bio, bool mark_dirty); extern void bio_set_pages_dirty(struct bio *bio); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 9efacabaa2f7..44e1066f7446 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1877,6 +1877,13 @@ static inline int bio_split_rw_at(struct bio *bio, return bio_split_io_at(bio, lim, segs, max_bytes, lim->dma_alignment); } +static inline int bio_iov_iter_get_bdev_pages(struct bio *bio, + struct iov_iter *iter, struct block_device *bdev) +{ + return bio_iov_iter_get_pages_aligned(bio, iter, + bdev_logical_block_size(bdev) - 1); +} + #define DEFINE_IO_COMP_BATCH(name) struct io_comp_batch name = { } #endif /* _LINUX_BLKDEV_H */