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block: add bio_kmalloc() 

Not all callers need (or want!) the mempool backing guarentee, it
essentially means that you can only use bio_alloc() for short allocations
and not for preallocating some bio's at setup or init time.

So add bio_kmalloc() which does the same thing as bio_alloc(), except
it just uses kmalloc() as the backing instead of the bio mempools.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe 2008-09-11 13:17:37 +02:00
parent 3e6053d76d
commit 0a0d96b03a
2 changed files with 76 additions and 21 deletions
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80
fs/bio.c
View File

@ -59,26 +59,47 @@ struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, struct
{
struct bio_vec *bvl;
/*
* If 'bs' is given, lookup the pool and do the mempool alloc.
* If not, this is a bio_kmalloc() allocation and just do a
* kzalloc() for the exact number of vecs right away.
*/
if (bs) {
/*
* see comment near bvec_array define!
*/
switch (nr) {
case 1 : *idx = 0; break;
case 2 ... 4: *idx = 1; break;
case 5 ... 16: *idx = 2; break;
case 17 ... 64: *idx = 3; break;
case 65 ... 128: *idx = 4; break;
case 129 ... BIO_MAX_PAGES: *idx = 5; break;
case 1:
*idx = 0;
break;
case 2 ... 4:
*idx = 1;
break;
case 5 ... 16:
*idx = 2;
break;
case 17 ... 64:
*idx = 3;
break;
case 65 ... 128:
*idx = 4;
break;
case 129 ... BIO_MAX_PAGES:
*idx = 5;
break;
default:
return NULL;
}
/*
* idx now points to the pool we want to allocate from
*/
bvl = mempool_alloc(bs->bvec_pools[*idx], gfp_mask);
if (bvl)
memset(bvl, 0, bvec_nr_vecs(*idx) * sizeof(struct bio_vec));
memset(bvl, 0,
bvec_nr_vecs(*idx) * sizeof(struct bio_vec));
} else
bvl = kzalloc(nr * sizeof(struct bio_vec), gfp_mask);
return bvl;
}
@ -107,6 +128,12 @@ static void bio_fs_destructor(struct bio *bio)
bio_free(bio, fs_bio_set);
}
static void bio_kmalloc_destructor(struct bio *bio)
{
kfree(bio->bi_io_vec);
kfree(bio);
}
void bio_init(struct bio *bio)
{
memset(bio, 0, sizeof(*bio));
@ -119,19 +146,25 @@ void bio_init(struct bio *bio)
* bio_alloc_bioset - allocate a bio for I/O
* @gfp_mask: the GFP_ mask given to the slab allocator
* @nr_iovecs: number of iovecs to pre-allocate
* @bs: the bio_set to allocate from
* @bs: the bio_set to allocate from. If %NULL, just use kmalloc
*
* Description:
* bio_alloc_bioset will first try it's on mempool to satisfy the allocation.
* bio_alloc_bioset will first 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.
* for a &struct bio to become free. If a %NULL @bs is passed in, we will
* fall back to just using @kmalloc to allocate the required memory.
*
* allocate bio and iovecs from the memory pools specified by the
* bio_set structure.
* bio_set structure, or @kmalloc if none given.
**/
struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
{
struct bio *bio = mempool_alloc(bs->bio_pool, gfp_mask);
struct bio *bio;
if (bs)
bio = mempool_alloc(bs->bio_pool, gfp_mask);
else
bio = kmalloc(sizeof(*bio), gfp_mask);
if (likely(bio)) {
struct bio_vec *bvl = NULL;
@ -142,7 +175,10 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
if (unlikely(!bvl)) {
if (bs)
mempool_free(bio, bs->bio_pool);
else
kfree(bio);
bio = NULL;
goto out;
}
@ -165,6 +201,23 @@ struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs)
return bio;
}
/*
* Like bio_alloc(), but doesn't use a mempool backing. This means that
* it CAN fail, but while bio_alloc() can only be used for allocations
* that have a short (finite) life span, bio_kmalloc() should be used
* for more permanent bio allocations (like allocating some bio's for
* initalization or setup purposes).
*/
struct bio *bio_kmalloc(gfp_t gfp_mask, int nr_iovecs)
{
struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
if (bio)
bio->bi_destructor = bio_kmalloc_destructor;
return bio;
}
void zero_fill_bio(struct bio *bio)
{
unsigned long flags;
@ -1349,6 +1402,7 @@ static int __init init_bio(void)
subsys_initcall(init_bio);
EXPORT_SYMBOL(bio_alloc);
EXPORT_SYMBOL(bio_kmalloc);
EXPORT_SYMBOL(bio_put);
EXPORT_SYMBOL(bio_free);
EXPORT_SYMBOL(bio_endio);

1
include/linux/bio.h
View File

@ -308,6 +308,7 @@ extern struct bio_set *bioset_create(int, int);
extern void bioset_free(struct bio_set *);
extern struct bio *bio_alloc(gfp_t, int);
extern struct bio *bio_kmalloc(gfp_t, 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 *, struct bio_set *);