-struct nvme_bio_pair {
- struct bio b1, b2, *parent;
- struct bio_vec *bv1, *bv2;
- int err;
- atomic_t cnt;
-};
-
-static void nvme_bio_pair_endio(struct bio *bio, int err)
-{
- struct nvme_bio_pair *bp = bio->bi_private;
-
- if (err)
- bp->err = err;
-
- if (atomic_dec_and_test(&bp->cnt)) {
- bio_endio(bp->parent, bp->err);
- kfree(bp->bv1);
- kfree(bp->bv2);
- kfree(bp);
- }
-}
-
-static struct nvme_bio_pair *nvme_bio_split(struct bio *bio, int idx,
- int len, int offset)
-{
- struct nvme_bio_pair *bp;
-
- BUG_ON(len > bio->bi_size);
- BUG_ON(idx > bio->bi_vcnt);
-
- bp = kmalloc(sizeof(*bp), GFP_ATOMIC);
- if (!bp)
- return NULL;
- bp->err = 0;
-
- bp->b1 = *bio;
- bp->b2 = *bio;
-
- bp->b1.bi_size = len;
- bp->b2.bi_size -= len;
- bp->b1.bi_vcnt = idx;
- bp->b2.bi_idx = idx;
- bp->b2.bi_sector += len >> 9;
-
- if (offset) {
- bp->bv1 = kmalloc(bio->bi_max_vecs * sizeof(struct bio_vec),
- GFP_ATOMIC);
- if (!bp->bv1)
- goto split_fail_1;
-
- bp->bv2 = kmalloc(bio->bi_max_vecs * sizeof(struct bio_vec),
- GFP_ATOMIC);
- if (!bp->bv2)
- goto split_fail_2;
-
- memcpy(bp->bv1, bio->bi_io_vec,
- bio->bi_max_vecs * sizeof(struct bio_vec));
- memcpy(bp->bv2, bio->bi_io_vec,
- bio->bi_max_vecs * sizeof(struct bio_vec));
-
- bp->b1.bi_io_vec = bp->bv1;
- bp->b2.bi_io_vec = bp->bv2;
- bp->b2.bi_io_vec[idx].bv_offset += offset;
- bp->b2.bi_io_vec[idx].bv_len -= offset;
- bp->b1.bi_io_vec[idx].bv_len = offset;
- bp->b1.bi_vcnt++;
- } else
- bp->bv1 = bp->bv2 = NULL;
-
- bp->b1.bi_private = bp;
- bp->b2.bi_private = bp;
-
- bp->b1.bi_end_io = nvme_bio_pair_endio;
- bp->b2.bi_end_io = nvme_bio_pair_endio;
-
- bp->parent = bio;
- atomic_set(&bp->cnt, 2);
-
- return bp;
-
- split_fail_2:
- kfree(bp->bv1);
- split_fail_1:
- kfree(bp);
- return NULL;
-}
-