block: Add bio_clone_fast()

[~andy/linux] / fs / bio.c

diff --git a/fs/bio.c b/fs/bio.c
index 1628917e262a43e4ac99d3cea88bccbd4f9ccf22..00dc1893c6ee0956b060aac4f3ddd852e43ae5a6 100644 (file)
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -548,6 +548,66 @@ void __bio_clone(struct bio *bio, struct bio *bio_src)
 }
 EXPORT_SYMBOL(__bio_clone);
 
+/**
+ *     __bio_clone_fast - clone a bio that shares the original bio's biovec
+ *     @bio: destination bio
+ *     @bio_src: bio to clone
+ *
+ *     Clone a &bio. Caller will own the returned bio, but not
+ *     the actual data it points to. Reference count of returned
+ *     bio will be one.
+ *
+ *     Caller must ensure that @bio_src is not freed before @bio.
+ */
+void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
+{
+       BUG_ON(bio->bi_pool && BIO_POOL_IDX(bio) != BIO_POOL_NONE);
+
+       /*
+        * most users will be overriding ->bi_bdev with a new target,
+        * so we don't set nor calculate new physical/hw segment counts here
+        */
+       bio->bi_bdev = bio_src->bi_bdev;
+       bio->bi_flags |= 1 << BIO_CLONED;
+       bio->bi_rw = bio_src->bi_rw;
+       bio->bi_iter = bio_src->bi_iter;
+       bio->bi_io_vec = bio_src->bi_io_vec;
+}
+EXPORT_SYMBOL(__bio_clone_fast);
+
+/**
+ *     bio_clone_fast - clone a bio that shares the original bio's biovec
+ *     @bio: bio to clone
+ *     @gfp_mask: allocation priority
+ *     @bs: bio_set to allocate from
+ *
+ *     Like __bio_clone_fast, only also allocates the returned bio
+ */
+struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
+{
+       struct bio *b;
+
+       b = bio_alloc_bioset(gfp_mask, 0, bs);
+       if (!b)
+               return NULL;
+
+       __bio_clone_fast(b, bio);
+
+       if (bio_integrity(bio)) {
+               int ret;
+
+               ret = bio_integrity_clone(b, bio, gfp_mask);
+
+               if (ret < 0) {
+                       bio_put(b);
+                       return NULL;
+               }
+       }
+
+       return b;
+}
+EXPORT_SYMBOL(bio_clone_fast);
+
 /**
  *     bio_clone_bioset - clone a bio
  *     @bio_src: bio to clone