[PATCH 16/19] xfs: simplify xfs_rw_bdev

[Christoph Hellwig]

Delegate to bdev_rw_virt when operating on non-vmalloc memory and use
bio_add_vmalloc_chunk to insulate xfs from the details of adding vmalloc
memory to a bio.

Signed-off-by: Christoph Hellwig <h...@lst.de>
Reviewed-by: Damien Le Moal <dlem...@kernel.org>
Reviewed-by: Darrick J. Wong <djw...@kernel.org>
---
 fs/xfs/xfs_bio_io.c | 30 ++++++++++++------------------
 1 file changed, 12 insertions(+), 18 deletions(-)

diff --git a/fs/xfs/xfs_bio_io.c b/fs/xfs/xfs_bio_io.c
index fe21c76f75b8..2a736d10eafb 100644
--- a/fs/xfs/xfs_bio_io.c
+++ b/fs/xfs/xfs_bio_io.c
@@ -18,42 +18,36 @@ xfs_rw_bdev(
        enum req_op             op)
 
 {
-       unsigned int            is_vmalloc = is_vmalloc_addr(data);
-       unsigned int            left = count;
+       unsigned int            done = 0, added;
        int                     error;
        struct bio              *bio;
 
-       if (is_vmalloc && op == REQ_OP_WRITE)
-               flush_kernel_vmap_range(data, count);
+       op |= REQ_META | REQ_SYNC;
+       if (!is_vmalloc_addr(data))
+               return bdev_rw_virt(bdev, sector, data, count, op);
 
-       bio = bio_alloc(bdev, bio_max_vecs(left), op | REQ_META | REQ_SYNC,
-                       GFP_KERNEL);
+       bio = bio_alloc(bdev, bio_max_vecs(count), op, GFP_KERNEL);
        bio->bi_iter.bi_sector = sector;
 
        do {
-               struct page     *page = kmem_to_page(data);
-               unsigned int    off = offset_in_page(data);
-               unsigned int    len = min_t(unsigned, left, PAGE_SIZE - off);
-
-               while (bio_add_page(bio, page, len, off) != len) {
+               added = bio_add_vmalloc_chunk(bio, data + done, count - done);
+               if (!added) {
                        struct bio      *prev = bio;
 
-                       bio = bio_alloc(prev->bi_bdev, bio_max_vecs(left),
+                       bio = bio_alloc(prev->bi_bdev,
+                                       bio_max_vecs(count - done),
                                        prev->bi_opf, GFP_KERNEL);
                        bio->bi_iter.bi_sector = bio_end_sector(prev);
                        bio_chain(prev, bio);
-
                        submit_bio(prev);
                }
-
-               data += len;
-               left -= len;
-       } while (left > 0);
+               done += added;
+       } while (done < count);
 
        error = submit_bio_wait(bio);
        bio_put(bio);
 
-       if (is_vmalloc && op == REQ_OP_READ)
+       if (op == REQ_OP_READ)
                invalidate_kernel_vmap_range(data, count);
        return error;
 }
-- 
2.47.2