[PATCH v6 06/13] block: Consolidate bio_alloc_bioset(), bio_kmalloc()
From: Kent Overstreet
Date: Wed Aug 22 2012 - 13:06:49 EST
Previously, bio_kmalloc() and bio_alloc_bioset() behaved slightly
different because there was some almost-duplicated code - this fixes
that issue.
This'll also help with some future cleanups - there are a fair number of
functions that allocate bios (e.g. bio_clone()), and now they don't have
to be duplicated for bio_alloc(), bio_alloc_bioset(), and bio_kmalloc().
Signed-off-by: Kent Overstreet <koverstreet@xxxxxxxxxx>
CC: Jens Axboe <axboe@xxxxxxxxx>
---
fs/bio.c | 96 ++++++++++++++---------------------------------------
include/linux/bio.h | 18 +++++++---
2 files changed, 38 insertions(+), 76 deletions(-)
diff --git a/fs/bio.c b/fs/bio.c
index fac171f..aa67bf3 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -55,8 +55,7 @@ static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
* IO code that does not need private memory pools.
*/
struct bio_set *fs_bio_set;
-
-#define BIO_KMALLOC_POOL NULL
+EXPORT_SYMBOL(fs_bio_set);
/*
* Our slab pool management
@@ -293,33 +292,43 @@ EXPORT_SYMBOL(bio_reset);
**/
struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
{
+ unsigned front_pad;
+ unsigned inline_vecs;
unsigned long idx = BIO_POOL_NONE;
struct bio_vec *bvl = NULL;
struct bio *bio;
void *p;
- p = mempool_alloc(bs->bio_pool, gfp_mask);
+ if (nr_iovecs > UIO_MAXIOV)
+ return NULL;
+
+ if (bs == BIO_KMALLOC_POOL) {
+ p = kmalloc(sizeof(struct bio) +
+ nr_iovecs * sizeof(struct bio_vec),
+ gfp_mask);
+ front_pad = 0;
+ inline_vecs = nr_iovecs;
+ } else {
+ p = mempool_alloc(bs->bio_pool, gfp_mask);
+ front_pad = bs->front_pad;
+ inline_vecs = BIO_INLINE_VECS;
+ }
+
if (unlikely(!p))
return NULL;
- bio = p + bs->front_pad;
+ bio = p + front_pad;
bio_init(bio);
- bio->bi_pool = bs;
- if (unlikely(!nr_iovecs))
- goto out_set;
-
- if (nr_iovecs <= BIO_INLINE_VECS) {
- bvl = bio->bi_inline_vecs;
- nr_iovecs = BIO_INLINE_VECS;
- } else {
+ if (nr_iovecs > inline_vecs) {
bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
if (unlikely(!bvl))
goto err_free;
-
- nr_iovecs = bvec_nr_vecs(idx);
+ } else if (nr_iovecs) {
+ bvl = bio->bi_inline_vecs;
}
-out_set:
+
+ bio->bi_pool = bs;
bio->bi_flags |= idx << BIO_POOL_OFFSET;
bio->bi_max_vecs = nr_iovecs;
bio->bi_io_vec = bvl;
@@ -331,63 +340,6 @@ err_free:
}
EXPORT_SYMBOL(bio_alloc_bioset);
-/**
- * bio_alloc - allocate a new bio, memory pool backed
- * @gfp_mask: allocation mask to use
- * @nr_iovecs: number of iovecs
- *
- * bio_alloc will allocate a bio and associated bio_vec array that can hold
- * at least @nr_iovecs entries. Allocations will be done from the
- * fs_bio_set. Also see @bio_alloc_bioset and @bio_kmalloc.
- *
- * If %__GFP_WAIT is set, then bio_alloc will always be able to allocate
- * a bio. This is due to the mempool guarantees. To make this work, callers
- * must never allocate more than 1 bio at a time from this pool. Callers
- * that need to allocate more than 1 bio must always submit the previously
- * allocated bio for IO before attempting to allocate a new one. Failure to
- * do so can cause livelocks under memory pressure.
- *
- * RETURNS:
- * Pointer to new bio on success, NULL on failure.
- */
-struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
-{
- return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
-}
-EXPORT_SYMBOL(bio_alloc);
-
-/**
- * bio_kmalloc - allocate a bio for I/O using kmalloc()
- * @gfp_mask: the GFP_ mask given to the slab allocator
- * @nr_iovecs: number of iovecs to pre-allocate
- *
- * Description:
- * Allocate a new bio with @nr_iovecs bvecs. If @gfp_mask contains
- * %__GFP_WAIT, the allocation is guaranteed to succeed.
- *
- **/
-struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
-{
- struct bio *bio;
-
- if (nr_iovecs > UIO_MAXIOV)
- return NULL;
-
- bio = kmalloc(sizeof(struct bio) + nr_iovecs * sizeof(struct bio_vec),
- gfp_mask);
- if (unlikely(!bio))
- return NULL;
-
- bio_init(bio);
- bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET;
- bio->bi_max_vecs = nr_iovecs;
- bio->bi_io_vec = bio->bi_inline_vecs;
- bio->bi_pool = BIO_KMALLOC_POOL;
-
- return bio;
-}
-EXPORT_SYMBOL(bio_kmalloc);
-
void zero_fill_bio(struct bio *bio)
{
unsigned long flags;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 393c87e..b22c22b 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -212,12 +212,24 @@ extern void bio_pair_release(struct bio_pair *dbio);
extern struct bio_set *bioset_create(unsigned int, unsigned int);
extern void bioset_free(struct bio_set *);
-extern struct bio *bio_alloc(gfp_t, unsigned int);
-extern struct bio *bio_kmalloc(gfp_t, unsigned int);
extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
extern void bio_put(struct bio *);
extern void bio_free(struct bio *);
+extern struct bio_set *fs_bio_set;
+
+static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
+{
+ return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
+}
+
+#define BIO_KMALLOC_POOL NULL
+
+static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
+{
+ return bio_alloc_bioset(gfp_mask, nr_iovecs, BIO_KMALLOC_POOL);
+}
+
extern void bio_endio(struct bio *, int);
struct request_queue;
extern int bio_phys_segments(struct request_queue *, struct bio *);
@@ -305,8 +317,6 @@ struct biovec_slab {
struct kmem_cache *slab;
};
-extern struct bio_set *fs_bio_set;
-
/*
* a small number of entries is fine, not going to be performance critical.
* basically we just need to survive
--
1.7.12
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