block: Add bioset_init()/bioset_exit()

Similarly to mempool_init()/mempool_exit(), take a pointer indirection
out of allocation/freeing by allowing biosets to be embedded in other
structs.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/bio.c b/block/bio.c
index 06df6cf..ee182de 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -1856,22 +1856,84 @@ int biovec_init_pool(mempool_t *pool, int pool_entries)
        return mempool_init_slab_pool(pool, pool_entries, bp->slab);
 }
 
-void bioset_free(struct bio_set *bs)
+/*
+ * bioset_exit - exit a bioset initialized with bioset_init()
+ *
+ * May be called on a zeroed but uninitialized bioset (i.e. allocated with
+ * kzalloc()).
+ */
+void bioset_exit(struct bio_set *bs)
 {
        if (bs->rescue_workqueue)
                destroy_workqueue(bs->rescue_workqueue);
+       bs->rescue_workqueue = NULL;
 
        mempool_exit(&bs->bio_pool);
        mempool_exit(&bs->bvec_pool);
 
        bioset_integrity_free(bs);
-       bio_put_slab(bs);
+       if (bs->bio_slab)
+               bio_put_slab(bs);
+       bs->bio_slab = NULL;
+}
+EXPORT_SYMBOL(bioset_exit);
 
+void bioset_free(struct bio_set *bs)
+{
+       bioset_exit(bs);
        kfree(bs);
 }
 EXPORT_SYMBOL(bioset_free);
 
 /**
+ * bioset_init - Initialize 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
+ * @flags:     Flags to modify behavior, currently %BIOSET_NEED_BVECS
+ *              and %BIOSET_NEED_RESCUER
+ *
+ * Similar to bioset_create(), but initializes a passed-in bioset instead of
+ * separately allocating it.
+ */
+int bioset_init(struct bio_set *bs,
+               unsigned int pool_size,
+               unsigned int front_pad,
+               int flags)
+{
+       unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
+
+       bs->front_pad = front_pad;
+
+       spin_lock_init(&bs->rescue_lock);
+       bio_list_init(&bs->rescue_list);
+       INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
+
+       bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
+       if (!bs->bio_slab)
+               return -ENOMEM;
+
+       if (mempool_init_slab_pool(&bs->bio_pool, pool_size, bs->bio_slab))
+               goto bad;
+
+       if ((flags & BIOSET_NEED_BVECS) &&
+           biovec_init_pool(&bs->bvec_pool, pool_size))
+               goto bad;
+
+       if (!(flags & BIOSET_NEED_RESCUER))
+               return 0;
+
+       bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
+       if (!bs->rescue_workqueue)
+               goto bad;
+
+       return 0;
+bad:
+       bioset_exit(bs);
+       return -ENOMEM;
+}
+EXPORT_SYMBOL(bioset_init);
+
+/**
  * 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
@@ -1895,43 +1957,18 @@ struct bio_set *bioset_create(unsigned int pool_size,
                              unsigned int front_pad,
                              int flags)
 {
-       unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
        struct bio_set *bs;
 
        bs = kzalloc(sizeof(*bs), GFP_KERNEL);
        if (!bs)
                return NULL;
 
-       bs->front_pad = front_pad;
-
-       spin_lock_init(&bs->rescue_lock);
-       bio_list_init(&bs->rescue_list);
-       INIT_WORK(&bs->rescue_work, bio_alloc_rescue);
-
-       bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad);
-       if (!bs->bio_slab) {
+       if (bioset_init(bs, pool_size, front_pad, flags)) {
                kfree(bs);
                return NULL;
        }
 
-       if (mempool_init_slab_pool(&bs->bio_pool, pool_size, bs->bio_slab))
-               goto bad;
-
-       if ((flags & BIOSET_NEED_BVECS) &&
-           biovec_init_pool(&bs->bvec_pool, pool_size))
-               goto bad;
-
-       if (!(flags & BIOSET_NEED_RESCUER))
-               return bs;
-
-       bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
-       if (!bs->rescue_workqueue)
-               goto bad;
-
        return bs;
-bad:
-       bioset_free(bs);
-       return NULL;
 }
 EXPORT_SYMBOL(bioset_create);
 

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 720f726..fa3cf94 100644 (file)
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -406,6 +406,8 @@ static inline struct bio *bio_next_split(struct bio *bio, int sectors,
        return bio_split(bio, sectors, gfp, bs);
 }
 
+extern int bioset_init(struct bio_set *, unsigned int, unsigned int, int flags);
+extern void bioset_exit(struct bio_set *);
 extern struct bio_set *bioset_create(unsigned int, unsigned int, int flags);
 enum {
        BIOSET_NEED_BVECS = BIT(0),