block: move the bi_vcnt check out of __bio_try_merge_page

Move the bi_vcnt out of __bio_try_merge_page and into the two callers
that don't already have it in preparation for additional changes to
__bio_try_merge_page.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jinyoung Choi <j-young.choi@samsung.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20230724165433.117645-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bio.c b/block/bio.c
index 3ac72e60e7f11c4980e1709470ca15ed9c464e6e..3dcbe98580dcefc13928d47d3b796a03e9c372ef 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -945,20 +945,17 @@ static inline bool page_is_mergeable(const struct bio_vec *bv,
 static bool __bio_try_merge_page(struct bio *bio, struct page *page,
                unsigned int len, unsigned int off, bool *same_page)
 {
-       if (bio->bi_vcnt > 0) {
-               struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
-
-               if (page_is_mergeable(bv, page, len, off, same_page)) {
-                       if (bio->bi_iter.bi_size > UINT_MAX - len) {
-                               *same_page = false;
-                               return false;
-                       }
-                       bv->bv_len += len;
-                       bio->bi_iter.bi_size += len;
-                       return true;
-               }
+       struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
+
+       if (!page_is_mergeable(bv, page, len, off, same_page))
+               return false;
+       if (bio->bi_iter.bi_size > UINT_MAX - len) {
+               *same_page = false;
+               return false;
        }
-       return false;
+       bv->bv_len += len;
+       bio->bi_iter.bi_size += len;
+       return true;
 }
 
 /*
@@ -1127,11 +1124,13 @@ int bio_add_page(struct bio *bio, struct page *page,
        if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
                return 0;
 
-       if (!__bio_try_merge_page(bio, page, len, offset, &same_page)) {
-               if (bio_full(bio, len))
-                       return 0;
-               __bio_add_page(bio, page, len, offset);
-       }
+       if (bio->bi_vcnt > 0 &&
+           __bio_try_merge_page(bio, page, len, offset, &same_page))
+               return len;
+
+       if (bio_full(bio, len))
+               return 0;
+       __bio_add_page(bio, page, len, offset);
        return len;
 }
 EXPORT_SYMBOL(bio_add_page);
@@ -1205,13 +1204,13 @@ static int bio_iov_add_page(struct bio *bio, struct page *page,
 {
        bool same_page = false;
 
-       if (!__bio_try_merge_page(bio, page, len, offset, &same_page)) {
-               __bio_add_page(bio, page, len, offset);
+       if (bio->bi_vcnt > 0 &&
+           __bio_try_merge_page(bio, page, len, offset, &same_page)) {
+               if (same_page)
+                       bio_release_page(bio, page);
                return 0;
        }
-
-       if (same_page)
-               bio_release_page(bio, page);
+       __bio_add_page(bio, page, len, offset);
        return 0;
 }