block: check if page is mergeable in one helper

Now the check for deciding if one page is mergeable to current bvec
becomes a bit complicated, and we need to reuse the code before
adding pc page.

So move the check in one dedicated helper.

No function change.

Cc: Omar Sandoval <osandov@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bio.c b/block/bio.c
index cbd202250a327e16577a930a271ac15ebb0238f6..7ab7060a0e6ce5cca44e1ac34cf2bd5778e62ff1 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -647,6 +647,24 @@ struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
 }
 EXPORT_SYMBOL(bio_clone_fast);
 
+static inline bool page_is_mergeable(const struct bio_vec *bv,
+               struct page *page, unsigned int len, unsigned int off,
+               bool same_page)
+{
+       phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) +
+               bv->bv_offset + bv->bv_len - 1;
+       phys_addr_t page_addr = page_to_phys(page);
+
+       if (vec_end_addr + 1 != page_addr + off)
+               return false;
+       if (xen_domain() && !xen_biovec_phys_mergeable(bv, page))
+               return false;
+       if (same_page && (vec_end_addr & PAGE_MASK) != page_addr)
+               return false;
+
+       return true;
+}
+
 /**
  *     bio_add_pc_page -       attempt to add page to passthrough bio
  *     @q: the target queue
@@ -770,20 +788,12 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page,
 
        if (bio->bi_vcnt > 0) {
                struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
-               phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) +
-                       bv->bv_offset + bv->bv_len - 1;
-               phys_addr_t page_addr = page_to_phys(page);
-
-               if (vec_end_addr + 1 != page_addr + off)
-                       return false;
-               if (xen_domain() && !xen_biovec_phys_mergeable(bv, page))
-                       return false;
-               if (same_page && (vec_end_addr & PAGE_MASK) != page_addr)
-                       return false;
-
-               bv->bv_len += len;
-               bio->bi_iter.bi_size += len;
-               return true;
+
+               if (page_is_mergeable(bv, page, len, off, same_page)) {
+                       bv->bv_len += len;
+                       bio->bi_iter.bi_size += len;
+                       return true;
+               }
        }
        return false;
 }