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>
diff --git a/fs/bio.c b/fs/bio.c
index 3553029..e56e7685 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -60,25 +60,46 @@
struct bio_vec *bvl;
/*
- * see comment near bvec_array define!
+ * 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.
*/
- 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;
+ 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;
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));
+ /*
+ * 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));
+ } else
+ bvl = kzalloc(nr * sizeof(struct bio_vec), gfp_mask);
return bvl;
}
@@ -107,6 +128,12 @@
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 @@
* 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 @@
bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
if (unlikely(!bvl)) {
- mempool_free(bio, bs->bio_pool);
+ if (bs)
+ mempool_free(bio, bs->bio_pool);
+ else
+ kfree(bio);
bio = NULL;
goto out;
}
@@ -165,6 +201,23 @@
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 @@
subsys_initcall(init_bio);
EXPORT_SYMBOL(bio_alloc);
+EXPORT_SYMBOL(bio_kmalloc);
EXPORT_SYMBOL(bio_put);
EXPORT_SYMBOL(bio_free);
EXPORT_SYMBOL(bio_endio);