X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Fbio.c;h=bbc442b8c86722dbe69651fb593bfe7d3f6c936c;hb=c2642ab05b855d2d3b850ddf90dbb02b1b9358ac;hp=38d3e8023a0795273595b46ef8647ebaee9952e6;hpb=d779188d2baf436e67fe8816fca2ef53d246900f;p=linux-2.6

diff --git a/fs/bio.c b/fs/bio.c
index 38d3e8023a..bbc442b8c8 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -123,9 +123,10 @@ static void bio_fs_destructor(struct bio *bio)
 	bio_free(bio, fs_bio_set);
 }
 
-inline void bio_init(struct bio *bio)
+void bio_init(struct bio *bio)
 {
 	bio->bi_next = NULL;
+	bio->bi_bdev = NULL;
 	bio->bi_flags = 1 << BIO_UPTODATE;
 	bio->bi_rw = 0;
 	bio->bi_vcnt = 0;
@@ -252,7 +253,7 @@ inline int bio_hw_segments(request_queue_t *q, struct bio *bio)
  *	the actual data it points to. Reference count of returned
  * 	bio will be one.
  */
-inline void __bio_clone(struct bio *bio, struct bio *bio_src)
+void __bio_clone(struct bio *bio, struct bio *bio_src)
 {
 	request_queue_t *q = bdev_get_queue(bio_src->bi_bdev);
 
@@ -325,10 +326,31 @@ static int __bio_add_page(request_queue_t *q, struct bio *bio, struct page
 	if (unlikely(bio_flagged(bio, BIO_CLONED)))
 		return 0;
 
-	if (bio->bi_vcnt >= bio->bi_max_vecs)
+	if (((bio->bi_size + len) >> 9) > max_sectors)
 		return 0;
 
-	if (((bio->bi_size + len) >> 9) > max_sectors)
+	/*
+	 * For filesystems with a blocksize smaller than the pagesize
+	 * we will often be called with the same page as last time and
+	 * a consecutive offset.  Optimize this special case.
+	 */
+	if (bio->bi_vcnt > 0) {
+		struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1];
+
+		if (page == prev->bv_page &&
+		    offset == prev->bv_offset + prev->bv_len) {
+			prev->bv_len += len;
+			if (q->merge_bvec_fn &&
+			    q->merge_bvec_fn(q, bio, prev) < len) {
+				prev->bv_len -= len;
+				return 0;
+			}
+
+			goto done;
+		}
+	}
+
+	if (bio->bi_vcnt >= bio->bi_max_vecs)
 		return 0;
 
 	/*
@@ -382,6 +404,7 @@ static int __bio_add_page(request_queue_t *q, struct bio *bio, struct page
 	bio->bi_vcnt++;
 	bio->bi_phys_segments++;
 	bio->bi_hw_segments++;
+ done:
 	bio->bi_size += len;
 	return len;
 }