From: Christoph Hellwig Date: Wed, 11 Feb 2015 13:07:49 +0000 (+0100) Subject: block: handle the null_mapped flag correctly in blk_rq_map_user_iov X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=a0763b27bf24f028d8b049ad856b2ee031fb475d;p=deliverable%2Flinux.git block: handle the null_mapped flag correctly in blk_rq_map_user_iov The tape drivers (and the sg driver in a special case that doesn't matter here) use the null_mapped flag to tell blk_rq_map_user to not copy around any data into or out of the bounce buffers. blk_rq_map_user_iov never got that treatment, which didn't matter until I refactored blk_rq_map_user to be implemented in terms of blk_rq_map_user_iov. Signed-off-by: Christoph Hellwig Fixes: ddad8dd0a162 ("block: use blk_rq_map_user_iov to implement blk_rq_map_user") Signed-off-by: Jens Axboe --- diff --git a/block/blk-map.c b/block/blk-map.c index 0f22911f17dc..b8d2725324a6 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -93,6 +93,9 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, if (IS_ERR(bio)) return PTR_ERR(bio); + if (map_data && map_data->null_mapped) + bio->bi_flags |= (1 << BIO_NULL_MAPPED); + if (bio->bi_iter.bi_size != iter->count) { /* * Grab an extra reference to this bio, as bio_unmap_user()