From 0abc2a10389f0c9070f76ca906c7382788036b93 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 18 Dec 2017 15:40:44 +0800 Subject: block: fix blk_rq_append_bio Commit caa4b02476e3(blk-map: call blk_queue_bounce from blk_rq_append_bio) moves blk_queue_bounce() into blk_rq_append_bio(), but don't consider the fact that the bounced bio becomes invisible to caller since the parameter type is 'struct bio *'. Make it a pointer to a pointer to a bio, so the caller sees the right bio also after a bounce. Fixes: caa4b02476e3 ("blk-map: call blk_queue_bounce from blk_rq_append_bio") Cc: Christoph Hellwig Reported-by: Michele Ballabio (handling failure of blk_rq_append_bio(), only call bio_get() after blk_rq_append_bio() returns OK) Tested-by: Michele Ballabio Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-map.c | 38 ++++++++++++++++++++++---------------- 1 file changed, 22 insertions(+), 16 deletions(-) (limited to 'block/blk-map.c') diff --git a/block/blk-map.c b/block/blk-map.c index b21f8e86f120..d3a94719f03f 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -12,22 +12,29 @@ #include "blk.h" /* - * Append a bio to a passthrough request. Only works can be merged into - * the request based on the driver constraints. + * Append a bio to a passthrough request. Only works if the bio can be merged + * into the request based on the driver constraints. */ -int blk_rq_append_bio(struct request *rq, struct bio *bio) +int blk_rq_append_bio(struct request *rq, struct bio **bio) { - blk_queue_bounce(rq->q, &bio); + struct bio *orig_bio = *bio; + + blk_queue_bounce(rq->q, bio); if (!rq->bio) { - blk_rq_bio_prep(rq->q, rq, bio); + blk_rq_bio_prep(rq->q, rq, *bio); } else { - if (!ll_back_merge_fn(rq->q, rq, bio)) + if (!ll_back_merge_fn(rq->q, rq, *bio)) { + if (orig_bio != *bio) { + bio_put(*bio); + *bio = orig_bio; + } return -EINVAL; + } - rq->biotail->bi_next = bio; - rq->biotail = bio; - rq->__data_len += bio->bi_iter.bi_size; + rq->biotail->bi_next = *bio; + rq->biotail = *bio; + rq->__data_len += (*bio)->bi_iter.bi_size; } return 0; @@ -73,14 +80,12 @@ static int __blk_rq_map_user_iov(struct request *rq, * We link the bounce buffer in and could have to traverse it * later so we have to get a ref to prevent it from being freed */ - ret = blk_rq_append_bio(rq, bio); - bio_get(bio); + ret = blk_rq_append_bio(rq, &bio); if (ret) { - bio_endio(bio); __blk_rq_unmap_user(orig_bio); - bio_put(bio); return ret; } + bio_get(bio); return 0; } @@ -213,7 +218,7 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, int reading = rq_data_dir(rq) == READ; unsigned long addr = (unsigned long) kbuf; int do_copy = 0; - struct bio *bio; + struct bio *bio, *orig_bio; int ret; if (len > (queue_max_hw_sectors(q) << 9)) @@ -236,10 +241,11 @@ int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, if (do_copy) rq->rq_flags |= RQF_COPY_USER; - ret = blk_rq_append_bio(rq, bio); + orig_bio = bio; + ret = blk_rq_append_bio(rq, &bio); if (unlikely(ret)) { /* request is too big */ - bio_put(bio); + bio_put(orig_bio); return ret; } -- cgit v1.2.3 From 69e0927b3774563c19b5fb32e91d75edc147fb62 Mon Sep 17 00:00:00 2001 From: Douglas Gilbert Date: Sun, 14 Jan 2018 17:00:48 -0500 Subject: blk_rq_map_user_iov: fix error override During stress tests by syzkaller on the sg driver the block layer infrequently returns EINVAL. Closer inspection shows the block layer was trying to return ENOMEM (which is much more understandable) but for some reason overroad that useful error. Patch below does not show this (unchanged) line: ret =__blk_rq_map_user_iov(rq, map_data, &i, gfp_mask, copy); That 'ret' was being overridden when that function failed. Signed-off-by: Douglas Gilbert Signed-off-by: Jens Axboe --- block/blk-map.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'block/blk-map.c') diff --git a/block/blk-map.c b/block/blk-map.c index b21f8e86f120..209eb3b45c54 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -114,7 +114,7 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, unsigned long align = q->dma_pad_mask | queue_dma_alignment(q); struct bio *bio = NULL; struct iov_iter i; - int ret; + int ret = -EINVAL; if (!iter_is_iovec(iter)) goto fail; @@ -143,7 +143,7 @@ unmap_rq: __blk_rq_unmap_user(bio); fail: rq->bio = NULL; - return -EINVAL; + return ret; } EXPORT_SYMBOL(blk_rq_map_user_iov); -- cgit v1.2.3