block: bounce: don't access bio->bi_io_vec in copy_to_high_bio_irq
Firstly this patch introduces BVEC_ITER_ALL_INIT for iterating one bio
from start to end.
As we need to support multipage bvecs, don't access bio->bi_io_vec
in copy_to_high_bio_irq(), and just use the standard iterator for that.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/bounce.c b/block/bounce.c
index 0274c31..c35a3d7 100644
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -113,24 +113,30 @@ int init_emergency_isa_pool(void)
static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
{
unsigned char *vfrom;
- struct bio_vec tovec, *fromvec = from->bi_io_vec;
+ struct bio_vec tovec, fromvec;
struct bvec_iter iter;
+ /*
+ * The bio of @from is created by bounce, so we can iterate
+ * its bvec from start to end, but the @from->bi_iter can't be
+ * trusted because it might be changed by splitting.
+ */
+ struct bvec_iter from_iter = BVEC_ITER_ALL_INIT;
bio_for_each_segment(tovec, to, iter) {
- if (tovec.bv_page != fromvec->bv_page) {
+ fromvec = bio_iter_iovec(from, from_iter);
+ if (tovec.bv_page != fromvec.bv_page) {
/*
* fromvec->bv_offset and fromvec->bv_len might have
* been modified by the block layer, so use the original
* copy, bounce_copy_vec already uses tovec->bv_len
*/
- vfrom = page_address(fromvec->bv_page) +
+ vfrom = page_address(fromvec.bv_page) +
tovec.bv_offset;
bounce_copy_vec(&tovec, vfrom);
flush_dcache_page(tovec.bv_page);
}
-
- fromvec++;
+ bio_advance_iter(from, &from_iter, tovec.bv_len);
}
}