[RFC 10/13] block: factor out helper for bio allocation from cache

[Kanchan Joshi]

Factor the code to pull out bio_from_cache helper which is not tied to
kiocb. This is prep patch.

Signed-off-by: Kanchan Joshi <joshi.k at samsung.com>
---
 block/bio.c         | 43 ++++++++++++++++++++++++++-----------------
 include/linux/bio.h |  1 +
 2 files changed, 27 insertions(+), 17 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index 6fadc977cd7f..46d0f278d3aa 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1682,27 +1682,12 @@ int bioset_init_from_src(struct bio_set *bs, struct bio_set *src)
 }
 EXPORT_SYMBOL(bioset_init_from_src);
 
-/**
- * bio_alloc_kiocb - Allocate a bio from bio_set based on kiocb
- * @kiocb:	kiocb describing the IO
- * @nr_vecs:	number of iovecs to pre-allocate
- * @bs:		bio_set to allocate from
- *
- * Description:
- *    Like @bio_alloc_bioset, but pass in the kiocb. The kiocb is only
- *    used to check if we should dip into the per-cpu bio_set allocation
- *    cache. The allocation uses GFP_KERNEL internally. On return, the
- *    bio is marked BIO_PERCPU_CACHEABLE, and the final put of the bio
- *    MUST be done from process context, not hard/soft IRQ.
- *
- */
-struct bio *bio_alloc_kiocb(struct kiocb *kiocb, unsigned short nr_vecs,
-			    struct bio_set *bs)
+struct bio *bio_from_cache(unsigned short nr_vecs, struct bio_set *bs)
 {
 	struct bio_alloc_cache *cache;
 	struct bio *bio;
 
-	if (!(kiocb->ki_flags & IOCB_ALLOC_CACHE) || nr_vecs > BIO_INLINE_VECS)
+	if (nr_vecs > BIO_INLINE_VECS)
 		return bio_alloc_bioset(GFP_KERNEL, nr_vecs, bs);
 
 	cache = per_cpu_ptr(bs->cache, get_cpu());
@@ -1721,6 +1706,30 @@ struct bio *bio_alloc_kiocb(struct kiocb *kiocb, unsigned short nr_vecs,
 	bio_set_flag(bio, BIO_PERCPU_CACHE);
 	return bio;
 }
+EXPORT_SYMBOL_GPL(bio_from_cache);
+
+/**
+ * bio_alloc_kiocb - Allocate a bio from bio_set based on kiocb
+ * @kiocb:	kiocb describing the IO
+ * @nr_vecs:	number of iovecs to pre-allocate
+ * @bs:		bio_set to allocate from
+ *
+ * Description:
+ *    Like @bio_alloc_bioset, but pass in the kiocb. The kiocb is only
+ *    used to check if we should dip into the per-cpu bio_set allocation
+ *    cache. The allocation uses GFP_KERNEL internally. On return, the
+ *    bio is marked BIO_PERCPU_CACHEABLE, and the final put of the bio
+ *    MUST be done from process context, not hard/soft IRQ.
+ *
+ */
+struct bio *bio_alloc_kiocb(struct kiocb *kiocb, unsigned short nr_vecs,
+			    struct bio_set *bs)
+{
+	if (!(kiocb->ki_flags & IOCB_ALLOC_CACHE))
+		return bio_alloc_bioset(GFP_KERNEL, nr_vecs, bs);
+
+	return bio_from_cache(nr_vecs, bs);
+}
 EXPORT_SYMBOL_GPL(bio_alloc_kiocb);
 
 static int __init init_bio(void)
diff --git a/include/linux/bio.h b/include/linux/bio.h
index fe6bdfbbef66..77eceb2bda4b 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -358,6 +358,7 @@ struct bio *bio_alloc_bioset(gfp_t gfp, unsigned short nr_iovecs,
 		struct bio_set *bs);
 struct bio *bio_alloc_kiocb(struct kiocb *kiocb, unsigned short nr_vecs,
 		struct bio_set *bs);
+struct bio *bio_from_cache(unsigned short nr_vecs, struct bio_set *bs);
 struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned short nr_iovecs);
 extern void bio_put(struct bio *);
 
-- 
2.25.1