Users of bio_clone_fast() do not need its own bvecs.
Allocating bvec mempool for such users is waste of memory.
This variant allows them to create bioset without bvec mempool.
Signed-off-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx>
---
block/bio.c | 61 ++++++++++++++++++++++++++++++++++++++---------------
include/linux/bio.h | 1 +
2 files changed, 45 insertions(+), 17 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 3e6331d..98c5100 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -428,6 +428,9 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
front_pad = 0;
inline_vecs = nr_iovecs;
} else {
+ /* should not use nobvec bioset for nr_iovecs > 0 */
+ if (WARN_ON_ONCE(!bs->bvec_pool && nr_iovecs > 0))
+ return NULL;
/*
* generic_make_request() converts recursion to iteration; this
* means if we're running beneath it, any bios we allocate and
@@ -1900,20 +1903,9 @@ void bioset_free(struct bio_set *bs)
}
EXPORT_SYMBOL(bioset_free);
-/**
- * bioset_create - Create a bio_set
- * @pool_size: Number of bio and bio_vecs to cache in the mempool
- * @front_pad: Number of bytes to allocate in front of the returned bio
- *
- * Description:
- * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
- * to ask for a number of bytes to be allocated in front of the bio.
- * Front pad allocation is useful for embedding the bio inside
- * another structure, to avoid allocating extra data to go with the bio.
- * Note that the bio must be embedded at the END of that structure always,
- * or things will break badly.
- */
-struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
+static struct bio_set *__bioset_create(unsigned int pool_size,
+ unsigned int front_pad,
+ unsigned int create_bvec_pool)
{
unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
struct bio_set *bs;
@@ -1938,9 +1930,11 @@ struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
if (!bs->bio_pool)
goto bad;
- bs->bvec_pool = biovec_create_pool(pool_size);
- if (!bs->bvec_pool)
- goto bad;
+ if (create_bvec_pool) {
+ bs->bvec_pool = biovec_create_pool(pool_size);
+ if (!bs->bvec_pool)
+ goto bad;
+ }
bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
if (!bs->rescue_workqueue)
@@ -1951,8 +1945,41 @@ bad:
bioset_free(bs);
return NULL;
}
+
+/**
+ * bioset_create - Create a bio_set
+ * @pool_size: Number of bio and bio_vecs to cache in the mempool
+ * @front_pad: Number of bytes to allocate in front of the returned bio
+ *
+ * Description:
+ * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller
+ * to ask for a number of bytes to be allocated in front of the bio.
+ * Front pad allocation is useful for embedding the bio inside
+ * another structure, to avoid allocating extra data to go with the bio.
+ * Note that the bio must be embedded at the END of that structure always,
+ * or things will break badly.
+ */
+struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
+{
+ return __bioset_create(pool_size, front_pad, 1);
+}
EXPORT_SYMBOL(bioset_create);
+/**
+ * bioset_nobvec_create - Create a bio_set without bio_vec mempool
+ * @pool_size: Number of bio to cache in the mempool
+ * @front_pad: Number of bytes to allocate in front of the returned bio
+ *
+ * Description:
+ * Same functionality as bioset_create() except that mempool is not
+ * created for bio_vecs. Saving some memory for bio_clone_fast() users.
+ */
+struct bio_set *bioset_nobvec_create(unsigned int pool_size, unsigned int front_pad)
+{
+ return __bioset_create(pool_size, front_pad, 0);
+}
+EXPORT_SYMBOL(bioset_nobvec_create);
+
#ifdef CONFIG_BLK_CGROUP
/**
* bio_associate_current - associate a bio with %current
diff --git a/include/linux/bio.h b/include/linux/bio.h
index b39e500..7d7b2a7 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -342,6 +342,7 @@ static inline struct bio *bio_next_split(struct bio *bio, int sectors,
}
extern struct bio_set *bioset_create(unsigned int, unsigned int);
+extern struct bio_set *bioset_nobvec_create(unsigned int, unsigned int);
extern void bioset_free(struct bio_set *);
extern mempool_t *biovec_create_pool(int pool_entries);
--
1.9.3
--
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