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authorJunichi Nomura <j-nomura@ce.jp.nec.com>2014-10-03 17:27:12 -0400
committerJens Axboe <axboe@fb.com>2014-10-03 15:28:18 -0600
commitd8f429e1669b9709f5b669aac9d734dbe0640891 (patch)
treec14ac256f51a230b472ada1525d2e7275f266436 /block
parent11dfce509eaa35e8fc81cb50d0910c0e235fd7e2 (diff)
downloadblackbird-op-linux-d8f429e1669b9709f5b669aac9d734dbe0640891.tar.gz
blackbird-op-linux-d8f429e1669b9709f5b669aac9d734dbe0640891.zip
block: add bioset_create_nobvec()
Users of bio_clone_fast() do not want bios with their own bvecs. Allocating a bvec mempool as part of the bioset intended for such users is a waste of memory. bioset_create_nobvec() creates a bioset that doesn't have the bvec mempool. Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
-rw-r--r--block/bio.c61
1 files changed, 44 insertions, 17 deletions
diff --git a/block/bio.c b/block/bio.c
index 3e6331d25d90..3e6e1986a5b2 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,
+ bool 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, true);
+}
EXPORT_SYMBOL(bioset_create);
+/**
+ * bioset_create_nobvec - 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_create_nobvec(unsigned int pool_size, unsigned int front_pad)
+{
+ return __bioset_create(pool_size, front_pad, false);
+}
+EXPORT_SYMBOL(bioset_create_nobvec);
+
#ifdef CONFIG_BLK_CGROUP
/**
* bio_associate_current - associate a bio with %current
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