Commit fec2e705 authored by Keith Busch's avatar Keith Busch Committed by Jens Axboe
Browse files

block: check for valid bio while splitting 



We're already iterating every segment, so check these for a valid IO
lengths at the same time. Individual segment lengths will not be checked
on passthrough commands. The read/write command segments must be sized
to the dma alignment.

Signed-off-by: default avatarKeith Busch <kbusch@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent d7b1cdc9

block/blk-map.c

+1 −1
Original line number Diff line number Diff line
@@ -443,7 +443,7 @@ int blk_rq_append_bio(struct request *rq, struct bio *bio) 
	int ret;



	/* check that the data layout matches the hardware restrictions */

	ret = bio_split_rw_at(bio, lim, &nr_segs, max_bytes);

	ret = bio_split_io_at(bio, lim, &nr_segs, max_bytes, 0);

	if (ret) {

		/* if we would have to split the bio, copy instead */

		if (ret > 0)

block/blk-merge.c

+17 −4
Original line number Diff line number Diff line
@@ -279,25 +279,30 @@ static unsigned int bio_split_alignment(struct bio *bio, 
}



/**

 * bio_split_rw_at - check if and where to split a read/write bio

 * bio_split_io_at - check if and where to split a bio

 * @bio:  [in] bio to be split

 * @lim:  [in] queue limits to split based on

 * @segs: [out] number of segments in the bio with the first half of the sectors

 * @max_bytes: [in] maximum number of bytes per bio

 * @len_align_mask: [in] length alignment mask for each vector

 *

 * Find out if @bio needs to be split to fit the queue limits in @lim and a

 * maximum size of @max_bytes.  Returns a negative error number if @bio can't be

 * split, 0 if the bio doesn't have to be split, or a positive sector offset if

 * @bio needs to be split.

 */

int bio_split_rw_at(struct bio *bio, const struct queue_limits *lim,

		unsigned *segs, unsigned max_bytes)

int bio_split_io_at(struct bio *bio, const struct queue_limits *lim,

		unsigned *segs, unsigned max_bytes, unsigned len_align_mask)

{

	struct bio_vec bv, bvprv, *bvprvp = NULL;

	struct bvec_iter iter;

	unsigned nsegs = 0, bytes = 0;



	bio_for_each_bvec(bv, bio, iter) {

		if (bv.bv_offset & lim->dma_alignment ||

		    bv.bv_len & len_align_mask)

			return -EINVAL;



		/*

		 * If the queue doesn't support SG gaps and adding this

		 * offset would create a gap, disallow it.
@@ -339,8 +344,16 @@ int bio_split_rw_at(struct bio *bio, const struct queue_limits *lim, 
	 * Individual bvecs might not be logical block aligned. Round down the

	 * split size so that each bio is properly block size aligned, even if

	 * we do not use the full hardware limits.

	 *

	 * It is possible to submit a bio that can't be split into a valid io:

	 * there may either be too many discontiguous vectors for the max

	 * segments limit, or contain virtual boundary gaps without having a

	 * valid block sized split. A zero byte result means one of those

	 * conditions occured.

	 */

	bytes = ALIGN_DOWN(bytes, bio_split_alignment(bio, lim));

	if (!bytes)

		return -EINVAL;



	/*

	 * Bio splitting may cause subtle trouble such as hang when doing sync
@@ -350,7 +363,7 @@ int bio_split_rw_at(struct bio *bio, const struct queue_limits *lim, 
	bio_clear_polled(bio);

	return bytes >> SECTOR_SHIFT;

}

EXPORT_SYMBOL_GPL(bio_split_rw_at);

EXPORT_SYMBOL_GPL(bio_split_io_at);



struct bio *bio_split_rw(struct bio *bio, const struct queue_limits *lim,

		unsigned *nr_segs)

include/linux/bio.h

+2 −2
Original line number Diff line number Diff line
@@ -322,8 +322,8 @@ static inline void bio_next_folio(struct folio_iter *fi, struct bio *bio) 
void bio_trim(struct bio *bio, sector_t offset, sector_t size);

extern struct bio *bio_split(struct bio *bio, int sectors,

			     gfp_t gfp, struct bio_set *bs);

int bio_split_rw_at(struct bio *bio, const struct queue_limits *lim,

		unsigned *segs, unsigned max_bytes);

int bio_split_io_at(struct bio *bio, const struct queue_limits *lim,

		unsigned *segs, unsigned max_bytes, unsigned len_align);



/**

 * bio_next_split - get next @sectors from a bio, splitting if necessary

include/linux/blkdev.h

+7 −0
Original line number Diff line number Diff line
@@ -1870,6 +1870,13 @@ bdev_atomic_write_unit_max_bytes(struct block_device *bdev) 
	return queue_atomic_write_unit_max_bytes(bdev_get_queue(bdev));

}



static inline int bio_split_rw_at(struct bio *bio,

		const struct queue_limits *lim,

		unsigned *segs, unsigned max_bytes)

{

	return bio_split_io_at(bio, lim, segs, max_bytes, lim->dma_alignment);

}



#define DEFINE_IO_COMP_BATCH(name)	struct io_comp_batch name = { }



#endif /* _LINUX_BLKDEV_H */