block: fix bounce_clone_bio for passthrough bios

Now that bio_alloc_bioset does not fall back to kmalloc for a NULL
bio_set, handle that case explicitly and simplify the calling
conventions.

Based on an earlier patch from Chaitanya Kulkarni.

Fixes: 3175199ab0ac ("block: split bio_kmalloc from bio_alloc_bioset")
Reported-by: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bounce.c b/block/bounce.c
index fc55314..79d8122 100644 (file)
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -214,8 +214,7 @@ static void bounce_end_io_read_isa(struct bio *bio)
        __bounce_end_io_read(bio, &isa_page_pool);
 }
 
-static struct bio *bounce_clone_bio(struct bio *bio_src, gfp_t gfp_mask,
-               struct bio_set *bs)
+static struct bio *bounce_clone_bio(struct bio *bio_src, gfp_t gfp_mask)
 {
        struct bvec_iter iter;
        struct bio_vec bv;
@@ -242,8 +241,11 @@ static struct bio *bounce_clone_bio(struct bio *bio_src, gfp_t gfp_mask,
         *    asking for trouble and would force extra work on
         *    __bio_clone_fast() anyways.
         */
-
-       bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs);
+       if (bio_is_passthrough(bio_src))
+               bio = bio_kmalloc(gfp_mask, bio_segments(bio_src));
+       else
+               bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src),
+                                      &bounce_bio_set);
        if (!bio)
                return NULL;
        bio->bi_bdev            = bio_src->bi_bdev;
@@ -296,7 +298,6 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
        unsigned i = 0;
        bool bounce = false;
        int sectors = 0;
-       bool passthrough = bio_is_passthrough(*bio_orig);
 
        bio_for_each_segment(from, *bio_orig, iter) {
                if (i++ < BIO_MAX_PAGES)
@@ -307,14 +308,14 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
        if (!bounce)
                return;
 
-       if (!passthrough && sectors < bio_sectors(*bio_orig)) {
+       if (!bio_is_passthrough(*bio_orig) &&
+           sectors < bio_sectors(*bio_orig)) {
                bio = bio_split(*bio_orig, sectors, GFP_NOIO, &bounce_bio_split);
                bio_chain(bio, *bio_orig);
                submit_bio_noacct(*bio_orig);
                *bio_orig = bio;
        }
-       bio = bounce_clone_bio(*bio_orig, GFP_NOIO, passthrough ? NULL :
-                       &bounce_bio_set);
+       bio = bounce_clone_bio(*bio_orig, GFP_NOIO);
 
        /*
         * Bvec table can't be updated by bio_for_each_segment_all(),