block: Convert integrity to bvec_alloc_bs()

This adds a pointer to the bvec array to struct bio_integrity_payload,
instead of the bvecs always being inline; then the bvecs are allocated
with bvec_alloc_bs().

Changed bvec_alloc_bs() and bvec_free_bs() to take a pointer to a
mempool instead of the bioset, so that bio integrity can use a different
mempool for its bvecs, and thus avoid a potential deadlock.

This is eventually for immutable bio vecs - immutable bvecs aren't
useful if we still have to copy them, hence the need for the pointer.
Less code is always nice too, though.

Also, bio_integrity_alloc() was using fs_bio_set if no bio_set was
specified. This was wrong - using the bio_set doesn't protect us from
memory allocation failures, because we just used kmalloc for the
bio_integrity_payload. But it does introduce the possibility of
deadlock, if for some reason we weren't supposed to be using fs_bio_set.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Kent Overstreet 2012-10-12 15:29:33 -07:00
parent 6fda981caf
commit 9f060e2231
3 changed files with 67 additions and 107 deletions

View File

@ -27,48 +27,11 @@
#include <linux/workqueue.h>
#include <linux/slab.h>
struct integrity_slab {
struct kmem_cache *slab;
unsigned short nr_vecs;
char name[8];
};
#define IS(x) { .nr_vecs = x, .name = "bip-"__stringify(x) }
struct integrity_slab bip_slab[BIOVEC_NR_POOLS] __read_mostly = {
IS(1), IS(4), IS(16), IS(64), IS(128), IS(BIO_MAX_PAGES),
};
#undef IS
#define BIP_INLINE_VECS 4
static struct kmem_cache *bip_slab;
static struct workqueue_struct *kintegrityd_wq;
static inline unsigned int vecs_to_idx(unsigned int nr)
{
switch (nr) {
case 1:
return 0;
case 2 ... 4:
return 1;
case 5 ... 16:
return 2;
case 17 ... 64:
return 3;
case 65 ... 128:
return 4;
case 129 ... BIO_MAX_PAGES:
return 5;
default:
BUG();
}
}
static inline int use_bip_pool(unsigned int idx)
{
if (idx == BIOVEC_MAX_IDX)
return 1;
return 0;
}
/**
* bio_integrity_alloc - Allocate integrity payload and attach it to bio
* @bio: bio to attach integrity metadata to
@ -84,38 +47,41 @@ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
unsigned int nr_vecs)
{
struct bio_integrity_payload *bip;
unsigned int idx = vecs_to_idx(nr_vecs);
struct bio_set *bs = bio->bi_pool;
unsigned long idx = BIO_POOL_NONE;
unsigned inline_vecs;
if (!bs)
bs = fs_bio_set;
BUG_ON(bio == NULL);
bip = NULL;
/* Lower order allocations come straight from slab */
if (!use_bip_pool(idx))
bip = kmem_cache_alloc(bip_slab[idx].slab, gfp_mask);
/* Use mempool if lower order alloc failed or max vecs were requested */
if (bip == NULL) {
idx = BIOVEC_MAX_IDX; /* so we free the payload properly later */
if (!bs) {
bip = kmalloc(sizeof(struct bio_integrity_payload) +
sizeof(struct bio_vec) * nr_vecs, gfp_mask);
inline_vecs = nr_vecs;
} else {
bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask);
if (unlikely(bip == NULL)) {
printk(KERN_ERR "%s: could not alloc bip\n", __func__);
return NULL;
}
inline_vecs = BIP_INLINE_VECS;
}
if (unlikely(!bip))
return NULL;
memset(bip, 0, sizeof(*bip));
if (nr_vecs > inline_vecs) {
bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
bs->bvec_integrity_pool);
if (!bip->bip_vec)
goto err;
} else {
bip->bip_vec = bip->bip_inline_vecs;
}
bip->bip_slab = idx;
bip->bip_bio = bio;
bip->bip_vec = bip->bip_inline_vecs;
bio->bi_integrity = bip;
return bip;
err:
mempool_free(bip, bs->bio_integrity_pool);
return NULL;
}
EXPORT_SYMBOL(bio_integrity_alloc);
@ -131,20 +97,20 @@ void bio_integrity_free(struct bio *bio)
struct bio_integrity_payload *bip = bio->bi_integrity;
struct bio_set *bs = bio->bi_pool;
if (!bs)
bs = fs_bio_set;
BUG_ON(bip == NULL);
/* A cloned bio doesn't own the integrity metadata */
if (!bio_flagged(bio, BIO_CLONED) && !bio_flagged(bio, BIO_FS_INTEGRITY)
&& bip->bip_buf != NULL)
kfree(bip->bip_buf);
if (use_bip_pool(bip->bip_slab))
if (bs) {
if (bip->bip_slab != BIO_POOL_NONE)
bvec_free(bs->bvec_integrity_pool, bip->bip_vec,
bip->bip_slab);
mempool_free(bip, bs->bio_integrity_pool);
else
kmem_cache_free(bip_slab[bip->bip_slab].slab, bip);
} else {
kfree(bip);
}
bio->bi_integrity = NULL;
}
@ -747,13 +713,14 @@ EXPORT_SYMBOL(bio_integrity_clone);
int bioset_integrity_create(struct bio_set *bs, int pool_size)
{
unsigned int max_slab = vecs_to_idx(BIO_MAX_PAGES);
if (bs->bio_integrity_pool)
return 0;
bs->bio_integrity_pool =
mempool_create_slab_pool(pool_size, bip_slab[max_slab].slab);
bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, bip_slab);
bs->bvec_integrity_pool = biovec_create_pool(bs, pool_size);
if (!bs->bvec_integrity_pool)
return -1;
if (!bs->bio_integrity_pool)
return -1;
@ -766,13 +733,14 @@ void bioset_integrity_free(struct bio_set *bs)
{
if (bs->bio_integrity_pool)
mempool_destroy(bs->bio_integrity_pool);
if (bs->bvec_integrity_pool)
mempool_destroy(bs->bio_integrity_pool);
}
EXPORT_SYMBOL(bioset_integrity_free);
void __init bio_integrity_init(void)
{
unsigned int i;
/*
* kintegrityd won't block much but may burn a lot of CPU cycles.
* Make it highpri CPU intensive wq with max concurrency of 1.
@ -782,14 +750,10 @@ void __init bio_integrity_init(void)
if (!kintegrityd_wq)
panic("Failed to create kintegrityd\n");
for (i = 0 ; i < BIOVEC_NR_POOLS ; i++) {
unsigned int size;
size = sizeof(struct bio_integrity_payload)
+ bip_slab[i].nr_vecs * sizeof(struct bio_vec);
bip_slab[i].slab =
kmem_cache_create(bip_slab[i].name, size, 0,
SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
}
bip_slab = kmem_cache_create("bio_integrity_payload",
sizeof(struct bio_integrity_payload) +
sizeof(struct bio_vec) * BIP_INLINE_VECS,
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
if (!bip_slab)
panic("Failed to create slab\n");
}

View File

@ -160,12 +160,12 @@ unsigned int bvec_nr_vecs(unsigned short idx)
return bvec_slabs[idx].nr_vecs;
}
void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx)
void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx)
{
BIO_BUG_ON(idx >= BIOVEC_NR_POOLS);
if (idx == BIOVEC_MAX_IDX)
mempool_free(bv, bs->bvec_pool);
mempool_free(bv, pool);
else {
struct biovec_slab *bvs = bvec_slabs + idx;
@ -173,8 +173,8 @@ void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx)
}
}
struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx,
struct bio_set *bs)
struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
mempool_t *pool)
{
struct bio_vec *bvl;
@ -210,7 +210,7 @@ struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx,
*/
if (*idx == BIOVEC_MAX_IDX) {
fallback:
bvl = mempool_alloc(bs->bvec_pool, gfp_mask);
bvl = mempool_alloc(pool, gfp_mask);
} else {
struct biovec_slab *bvs = bvec_slabs + *idx;
gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
@ -253,7 +253,7 @@ static void bio_free(struct bio *bio)
if (bs) {
if (bio_has_allocated_vec(bio))
bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));
bvec_free(bs->bvec_pool, bio->bi_io_vec, BIO_POOL_IDX(bio));
/*
* If we have front padding, adjust the bio pointer before freeing
@ -442,11 +442,11 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
bio_init(bio);
if (nr_iovecs > inline_vecs) {
bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
if (!bvl && gfp_mask != saved_gfp) {
punt_bios_to_rescuer(bs);
gfp_mask = saved_gfp;
bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, bs->bvec_pool);
}
if (unlikely(!bvl))
@ -1661,20 +1661,11 @@ EXPORT_SYMBOL(bio_sector_offset);
* create memory pools for biovec's in a bio_set.
* use the global biovec slabs created for general use.
*/
static int biovec_create_pools(struct bio_set *bs, int pool_entries)
mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries)
{
struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX;
bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab);
if (!bs->bvec_pool)
return -ENOMEM;
return 0;
}
static void biovec_free_pools(struct bio_set *bs)
{
mempool_destroy(bs->bvec_pool);
return mempool_create_slab_pool(pool_entries, bp->slab);
}
void bioset_free(struct bio_set *bs)
@ -1685,8 +1676,10 @@ void bioset_free(struct bio_set *bs)
if (bs->bio_pool)
mempool_destroy(bs->bio_pool);
if (bs->bvec_pool)
mempool_destroy(bs->bvec_pool);
bioset_integrity_free(bs);
biovec_free_pools(bs);
bio_put_slab(bs);
kfree(bs);
@ -1731,7 +1724,8 @@ struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
if (!bs->bio_pool)
goto bad;
if (biovec_create_pools(bs, pool_size))
bs->bvec_pool = biovec_create_pool(bs, pool_size);
if (!bs->bvec_pool)
goto bad;
bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);

View File

@ -213,6 +213,7 @@ 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 mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries);
extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
extern void bio_put(struct bio *);
@ -288,8 +289,8 @@ extern struct bio *bio_copy_user_iov(struct request_queue *,
int, int, gfp_t);
extern int bio_uncopy_user(struct bio *);
void zero_fill_bio(struct bio *bio);
extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
extern unsigned int bvec_nr_vecs(unsigned short idx);
#ifdef CONFIG_BLK_CGROUP
@ -511,10 +512,11 @@ struct bio_set {
unsigned int front_pad;
mempool_t *bio_pool;
mempool_t *bvec_pool;
#if defined(CONFIG_BLK_DEV_INTEGRITY)
mempool_t *bio_integrity_pool;
mempool_t *bvec_integrity_pool;
#endif
mempool_t *bvec_pool;
/*
* Deadlock avoidance for stacking block drivers: see comments in