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authorKent Overstreet <kent.overstreet@gmail.com>2018-05-09 04:33:54 +0300
committerJens Axboe <axboe@kernel.dk>2018-05-14 22:16:10 +0300
commit45db54d58de0b7171fe1f0d1dfc14378e464949e (patch)
tree7710877ae0fa69ef957a8087785fb1e7e0d1e06d /block
parent38a72dac48f631c2a90b831a3847cde116f21d3a (diff)
downloadlinux-45db54d58de0b7171fe1f0d1dfc14378e464949e.tar.xz
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>
Diffstat (limited to 'block')
-rw-r--r--block/bio.c83
1 files changed, 51 insertions, 32 deletions
diff --git a/block/bio.c b/block/bio.c
index e849efff4616..858f56f3edcb 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -971,32 +971,16 @@ 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 (1) {
- if (!src_iter.bi_size) {
- src = src->bi_next;
- if (!src)
- break;
-
- src_iter = src->bi_iter;
- }
-
- if (!dst_iter.bi_size) {
- dst = dst->bi_next;
- if (!dst)
- break;
-
- dst_iter = dst->bi_iter;
- }
-
- src_bv = bio_iter_iovec(src, src_iter);
- dst_bv = bio_iter_iovec(dst, dst_iter);
+ 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);
@@ -1010,31 +994,66 @@ void bio_copy_data_iter(struct bio *dst, struct bvec_iter dst_iter,
kunmap_atomic(dst_p);
kunmap_atomic(src_p);
- bio_advance_iter(src, &src_iter, bytes);
- bio_advance_iter(dst, &dst_iter, bytes);
+ 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 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.
+ * 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)
{
- bio_copy_data_iter(dst, dst->bi_iter,
- src, src->bi_iter);
+ 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;
+ if (!src)
+ break;
+
+ src_iter = src->bi_iter;
+ }
+
+ if (!dst_iter.bi_size) {
+ dst = dst->bi_next;
+ if (!dst)
+ break;
+
+ dst_iter = dst->bi_iter;
+ }
+
+ bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
+ }
+}
+EXPORT_SYMBOL(bio_list_copy_data);
+
struct bio_map_data {
int is_our_pages;
struct iov_iter iter;