diff options
| -rw-r--r-- | fs/bio.c | 110 | ||||
| -rw-r--r-- | include/linux/bio.h | 16 |
2 files changed, 49 insertions, 77 deletions
@@ -55,6 +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; +EXPORT_SYMBOL(fs_bio_set); /* * Our slab pool management @@ -301,39 +302,58 @@ EXPORT_SYMBOL(bio_reset); * @bs: the bio_set to allocate from. * * Description: - * bio_alloc_bioset will try its own mempool to satisfy the allocation. - * If %__GFP_WAIT is set then we will block on the internal pool waiting - * for a &struct bio to become free. - **/ + * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is + * backed by the @bs's mempool. + * + * When @bs is not NULL, 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 deadlocks under memory pressure. + * + * RETURNS: + * Pointer to new bio on success, NULL on failure. + */ 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 (!bs) { + if (nr_iovecs > UIO_MAXIOV) + return NULL; + + 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; @@ -345,62 +365,6 @@ 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; - - 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 04944c91fae..fbe35b17555 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -212,11 +212,21 @@ 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 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); +} + +static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs) +{ + return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL); +} + extern void bio_endio(struct bio *, int); struct request_queue; extern int bio_phys_segments(struct request_queue *, struct bio *); @@ -304,8 +314,6 @@ 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 |