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: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-map.c b/block/blk-map.c
index 92b7e19b1a1f7e582d47e7d54272863d7d31f469..ca4f5cf0003889228f12cd98289e89e3bda74d04 100644 (file)
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -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)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 70d704615be52046c46518746d15ce584515d7a2..cffc0fe48d8a3b6bc25e082c19bc18b2919124bf 100644 (file)
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -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 @@ split:
         * 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 @@ split:
        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)

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 27cbff5b0356e26f168dd6754f3379ae013935e9..13d1df02656a8e0dd5ed3156021c5e61f887caea 100644 (file)
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -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

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 7709d55adc236dd487d6074ad69a7dcb2b8bdc3b..9efacabaa2f73bab2c9facf86893c7da6d999578 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -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 */