block: Split out bio_list_copy_data()
Found a bug (with ASAN) where we were passing a bio to bio_copy_data()
with bi_next not NULL, when it should have been - a driver had left
bi_next set to something after calling bio_endio().
Since the normal case is only copying single bios, split out
bio_list_copy_data() to avoid more bugs like this in the future.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/bio.c b/block/bio.c
index e849eff..858f56f3 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -971,13 +971,67 @@ void bio_advance(struct bio *bio, unsigned bytes)
}
EXPORT_SYMBOL(bio_advance);
-void bio_copy_data_iter(struct bio *dst, struct bvec_iter dst_iter,
- struct bio *src, struct bvec_iter src_iter)
+void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
+ struct bio *src, struct bvec_iter *src_iter)
{
struct bio_vec src_bv, dst_bv;
void *src_p, *dst_p;
unsigned bytes;
+ while (src_iter->bi_size && dst_iter->bi_size) {
+ src_bv = bio_iter_iovec(src, *src_iter);
+ dst_bv = bio_iter_iovec(dst, *dst_iter);
+
+ bytes = min(src_bv.bv_len, dst_bv.bv_len);
+
+ src_p = kmap_atomic(src_bv.bv_page);
+ dst_p = kmap_atomic(dst_bv.bv_page);
+
+ memcpy(dst_p + dst_bv.bv_offset,
+ src_p + src_bv.bv_offset,
+ bytes);
+
+ kunmap_atomic(dst_p);
+ kunmap_atomic(src_p);
+
+ bio_advance_iter(src, src_iter, bytes);
+ bio_advance_iter(dst, dst_iter, bytes);
+ }
+}
+EXPORT_SYMBOL(bio_copy_data_iter);
+
+/**
+ * bio_copy_data - copy contents of data buffers from one bio to another
+ * @src: source bio
+ * @dst: destination bio
+ *
+ * Stops when it reaches the end of either @src or @dst - that is, copies
+ * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
+ */
+void bio_copy_data(struct bio *dst, struct bio *src)
+{
+ struct bvec_iter src_iter = src->bi_iter;
+ struct bvec_iter dst_iter = dst->bi_iter;
+
+ bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
+}
+EXPORT_SYMBOL(bio_copy_data);
+
+/**
+ * bio_list_copy_data - copy contents of data buffers from one chain of bios to
+ * another
+ * @src: source bio list
+ * @dst: destination bio list
+ *
+ * Stops when it reaches the end of either the @src list or @dst list - that is,
+ * copies min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of
+ * bios).
+ */
+void bio_list_copy_data(struct bio *dst, struct bio *src)
+{
+ struct bvec_iter src_iter = src->bi_iter;
+ struct bvec_iter dst_iter = dst->bi_iter;
+
while (1) {
if (!src_iter.bi_size) {
src = src->bi_next;
@@ -995,45 +1049,10 @@ void bio_copy_data_iter(struct bio *dst, struct bvec_iter dst_iter,
dst_iter = dst->bi_iter;
}
- src_bv = bio_iter_iovec(src, src_iter);
- dst_bv = bio_iter_iovec(dst, dst_iter);
-
- bytes = min(src_bv.bv_len, dst_bv.bv_len);
-
- src_p = kmap_atomic(src_bv.bv_page);
- dst_p = kmap_atomic(dst_bv.bv_page);
-
- memcpy(dst_p + dst_bv.bv_offset,
- src_p + src_bv.bv_offset,
- bytes);
-
- kunmap_atomic(dst_p);
- kunmap_atomic(src_p);
-
- bio_advance_iter(src, &src_iter, bytes);
- bio_advance_iter(dst, &dst_iter, bytes);
+ bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
}
}
-EXPORT_SYMBOL(bio_copy_data_iter);
-
-/**
- * bio_copy_data - copy contents of data buffers from one chain of bios to
- * another
- * @src: source bio list
- * @dst: destination bio list
- *
- * If @src and @dst are single bios, bi_next must be NULL - otherwise, treats
- * @src and @dst as linked lists of bios.
- *
- * Stops when it reaches the end of either @src or @dst - that is, copies
- * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).
- */
-void bio_copy_data(struct bio *dst, struct bio *src)
-{
- bio_copy_data_iter(dst, dst->bi_iter,
- src, src->bi_iter);
-}
-EXPORT_SYMBOL(bio_copy_data);
+EXPORT_SYMBOL(bio_list_copy_data);
struct bio_map_data {
int is_our_pages;
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index ccfcf54..d8aff7f 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -1285,7 +1285,7 @@ static void pkt_start_write(struct pktcdvd_device *pd, struct packet_data *pkt)
* Fill-in bvec with data from orig_bios.
*/
spin_lock(&pkt->lock);
- bio_copy_data(pkt->w_bio, pkt->orig_bios.head);
+ bio_list_copy_data(pkt->w_bio, pkt->orig_bios.head);
pkt_set_state(pkt, PACKET_WRITE_WAIT_STATE);
spin_unlock(&pkt->lock);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 5a6ee95..98b175c 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -505,9 +505,10 @@ static inline void bio_flush_dcache_pages(struct bio *bi)
}
#endif
-extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter dst_iter,
- struct bio *src, struct bvec_iter src_iter);
+extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
+ struct bio *src, struct bvec_iter *src_iter);
extern void bio_copy_data(struct bio *dst, struct bio *src);
+extern void bio_list_copy_data(struct bio *dst, struct bio *src);
extern void bio_free_pages(struct bio *bio);
extern struct bio *bio_copy_user_iov(struct request_queue *,
