From: Kent Overstreet <kent.overstreet@gmail.com>
To: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
linux-mm@kvack.org, Jens Axboe <axboe@kernel.dk>,
Ingo Molnar <mingo@kernel.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Subject: [PATCH 06/10] block: Split out bio_list_copy_data()
Date: Tue, 8 May 2018 21:33:54 -0400 [thread overview]
Message-ID: <20180509013358.16399-7-kent.overstreet@gmail.com> (raw)
In-Reply-To: <20180509013358.16399-1-kent.overstreet@gmail.com>
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>
---
block/bio.c | 83 +++++++++++++++++++++++++----------------
drivers/block/pktcdvd.c | 2 +-
include/linux/bio.h | 5 ++-
3 files changed, 55 insertions(+), 35 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index d7bd765e9e..c58544d4bc 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;
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index c61d20c9f3..00ea788b17 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 5a6ee955a8..98b175cc00 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 *,
--
2.17.0
next prev parent reply other threads:[~2018-05-09 1:34 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-09 1:33 [PATCH 00/10] Misc block layer patches for bcachefs Kent Overstreet
2018-05-09 1:33 ` [PATCH 01/10] mempool: Add mempool_init()/mempool_exit() Kent Overstreet
2018-05-09 7:54 ` Johannes Thumshirn
2018-05-11 21:11 ` Jens Axboe
2018-05-14 19:11 ` Kent Overstreet
2018-05-09 1:33 ` [PATCH 02/10] block: Convert bio_set to mempool_init() Kent Overstreet
2018-05-18 16:20 ` Christoph Hellwig
2018-05-18 16:21 ` Christoph Hellwig
2018-05-18 17:36 ` Kent Overstreet
2018-05-09 1:33 ` [PATCH 03/10] block: Add bioset_init()/bioset_exit() Kent Overstreet
2018-05-09 1:33 ` [PATCH 04/10] block: Use bioset_init() for fs_bio_set Kent Overstreet
2018-05-09 1:33 ` [PATCH 05/10] block: Add bio_copy_data_iter(), zero_fill_bio_iter() Kent Overstreet
2018-05-09 1:33 ` Kent Overstreet [this message]
2018-05-09 1:33 ` [PATCH 07/10] block: Add missing flush_dcache_page() call Kent Overstreet
2018-05-09 1:33 ` [PATCH 08/10] block: Add warning for bi_next not NULL in bio_endio() Kent Overstreet
2018-05-09 1:33 ` [PATCH 09/10] block: Export bio check/set pages_dirty Kent Overstreet
2018-05-09 1:33 ` [PATCH 10/10] block: Add sysfs entry for fua support Kent Overstreet
2018-05-11 21:13 ` [PATCH 00/10] Misc block layer patches for bcachefs Jens Axboe
2018-05-18 16:23 ` Christoph Hellwig
2018-05-18 16:33 ` Jens Axboe
2018-05-14 19:24 ` Jens Axboe
2018-05-14 19:24 ` Kent Overstreet
2018-05-17 20:54 ` Bart Van Assche
2018-05-18 9:06 ` Kent Overstreet
2018-05-18 15:12 ` Bart Van Assche
2018-05-20 22:17 ` Kent Overstreet
2018-05-20 22:19 ` Bart Van Assche
2018-05-20 22:31 ` Kent Overstreet
2018-05-20 22:35 ` Bart Van Assche
2018-05-20 23:00 ` Kent Overstreet
2018-05-20 23:10 ` Bart Van Assche
2018-05-20 23:21 ` Kent Overstreet
2018-05-20 23:40 ` Bart Van Assche
2018-05-20 23:58 ` Kent Overstreet
2018-05-21 15:11 ` Bart Van Assche
2018-05-21 18:37 ` Omar Sandoval
2018-05-21 18:46 ` Bart Van Assche
2018-05-22 22:01 ` Bart Van Assche
[not found] <20180518074918.13816-1-kent.overstreet@gmail.com>
2018-05-18 7:49 ` [PATCH 06/10] block: Split out bio_list_copy_data() Kent Overstreet
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