two simple block patches

two simple block patches

[Christoph Hellwig]

First is a fix for a regression recently introduced by me in the
block/for-next tree, and the second is a trivial removal of an
unused function.

[PATCH 1/2] block: handle the null_mapped flag correctly in blk_rq_map_user_iov

[Christoph Hellwig]

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 <hch@lst.de>
---
 block/blk-map.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/blk-map.c b/block/blk-map.c
index 0f22911..b8d2725 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()
-- 
1.9.1

[PATCH 2/2] block: remove unused function blk_bio_map_sg

[Christoph Hellwig]

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-merge.c      | 29 -----------------------------
 include/linux/blkdev.h |  2 --
 2 files changed, 31 deletions(-)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 89b97b5..891611a 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -283,35 +283,6 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
 }
 EXPORT_SYMBOL(blk_rq_map_sg);
 
-/**
- * blk_bio_map_sg - map a bio to a scatterlist
- * @q: request_queue in question
- * @bio: bio being mapped
- * @sglist: scatterlist being mapped
- *
- * Note:
- *    Caller must make sure sg can hold bio->bi_phys_segments entries
- *
- * Will return the number of sg entries setup
- */
-int blk_bio_map_sg(struct request_queue *q, struct bio *bio,
-		   struct scatterlist *sglist)
-{
-	struct scatterlist *sg = NULL;
-	int nsegs;
-	struct bio *next = bio->bi_next;
-	bio->bi_next = NULL;
-
-	nsegs = __blk_bios_map_sg(q, bio, sglist, &sg);
-	bio->bi_next = next;
-	if (sg)
-		sg_mark_end(sg);
-
-	BUG_ON(bio->bi_phys_segments && nsegs > bio->bi_phys_segments);
-	return nsegs;
-}
-EXPORT_SYMBOL(blk_bio_map_sg);
-
 static inline int ll_new_hw_segment(struct request_queue *q,
 				    struct request *req,
 				    struct bio *bio)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index bf4ef66..7f9a516 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1049,8 +1049,6 @@ extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
 extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
 
 extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
-extern int blk_bio_map_sg(struct request_queue *q, struct bio *bio,
-			  struct scatterlist *sglist);
 extern void blk_dump_rq_flags(struct request *, char *);
 extern long nr_blockdev_pages(void);
 
-- 
1.9.1

Re: [PATCH 1/2] block: handle the null_mapped flag correctly in blk_rq_map_user_iov

[Jens Axboe]

On 02/11/2015 06:07 AM, Christoph Hellwig wrote:
> 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.

So this fixes a regression caused by:

commit ddad8dd0a162fde61646a627a3017c258601dc8a
Author: Christoph Hellwig <hch@lst.de>
Date:   Sun Jan 18 16:16:29 2015 +0100

     block: use blk_rq_map_user_iov to implement blk_rq_map_user

     Signed-off-by: Christoph Hellwig <hch@lst.de>
     Reviewed-by: Ming Lei <tom.leiming@gmail.com>
     Signed-off-by: Jens Axboe <axboe@fb.com>

which we should probably note in the commit. I'll add that.


-- 
Jens Axboe