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Date: Wed, 1 Apr 2009 20:04:41 +0900
From: Tejun Heo <tj@...nel.org>
To: axboe@...nel.dk, bharrosh@...asas.com, linux-kernel@...r.kernel.org
Cc: Tejun Heo <tj@...nel.org>
Subject: [PATCH 5/8] bio: fix bio_kmalloc()
Impact: fix bio_kmalloc() and its destruction path
bio_kmalloc() was broken in two ways.
* bvec_alloc_bs() first allocates bvec using kmalloc() and then
ignores it and allocates again like non-kmalloc bvecs.
* bio_kmalloc_destructor() didn't check for and free bio integrity
data.
This patch fixes the above problems. kmalloc bvec allocation is moved
to bio_alloc_bioset(). While at it, also make the following changes.
* define and use BIO_POOL_NONE so that pool index check in
bvec_free_bs() triggers if inline or kmalloc allocated bvec gets
there.
* relocate destructors on top of each allocation function so that how
they're used is more clear.
Signed-off-by: Tejun Heo <tj@...nel.org>
---
fs/bio.c | 74 +++++++++++++++++++++++++++++----------------------
include/linux/bio.h | 1 +
2 files changed, 43 insertions(+), 32 deletions(-)
diff --git a/fs/bio.c b/fs/bio.c
index 7574839..e15e457 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -169,14 +169,6 @@ struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx,
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)
- bvl = kmalloc(nr * sizeof(struct bio_vec), gfp_mask);
-
- /*
* see comment near bvec_array define!
*/
switch (nr) {
@@ -254,21 +246,6 @@ void bio_free(struct bio *bio, struct bio_set *bs)
mempool_free(p, bs->bio_pool);
}
-/*
- * default destructor for a bio allocated with bio_alloc_bioset()
- */
-static void bio_fs_destructor(struct bio *bio)
-{
- bio_free(bio, fs_bio_set);
-}
-
-static void bio_kmalloc_destructor(struct bio *bio)
-{
- if (bio_has_allocated_vec(bio))
- kfree(bio->bi_io_vec);
- kfree(bio);
-}
-
void bio_init(struct bio *bio)
{
memset(bio, 0, sizeof(*bio));
@@ -297,7 +274,7 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
{
struct bio_vec *bvl = NULL;
struct bio *bio = NULL;
- unsigned long idx = 0;
+ unsigned long idx = BIO_POOL_NONE;
void *p = NULL;
if (bs) {
@@ -319,12 +296,15 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
if (nr_iovecs <= BIO_INLINE_VECS) {
bvl = bio->bi_inline_vecs;
nr_iovecs = BIO_INLINE_VECS;
- } else {
+ } else if (bs) {
bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs);
if (unlikely(!bvl))
goto err_free;
-
nr_iovecs = bvec_nr_vecs(idx);
+ } else {
+ bvl = kmalloc(nr_iovecs * sizeof(struct bio_vec), gfp_mask);
+ if (unlikely(!bvl))
+ goto err_free;
}
bio->bi_flags |= idx << BIO_POOL_OFFSET;
bio->bi_max_vecs = nr_iovecs;
@@ -342,6 +322,22 @@ err:
return NULL;
}
+static void bio_fs_destructor(struct bio *bio)
+{
+ bio_free(bio, fs_bio_set);
+}
+
+/**
+ * bio_alloc - allocate a new bio, memory pool backed
+ * @gfp_mask: allocation mask to use
+ * @nr_iovecs: number of iovecs
+ *
+ * Allocate a new bio with @nr_iovecs bvecs. If @gfp_mask
+ * contains __GFP_WAIT, the allocation is guaranteed to succeed.
+ *
+ * RETURNS:
+ * Pointer to new bio on success, NULL on failure.
+ */
struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs)
{
struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
@@ -352,12 +348,26 @@ 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).
+static void bio_kmalloc_destructor(struct bio *bio)
+{
+ if (bio_has_allocated_vec(bio))
+ kfree(bio->bi_io_vec);
+ if (bio_integrity(bio))
+ bio_integrity_free(bio);
+ kfree(bio);
+}
+
+/**
+ * bio_kmalloc - allocate a new bio
+ * @gfp_mask: allocation mask to use
+ * @nr_iovecs: number of iovecs
+ *
+ * Similar to bio_alloc() but uses regular kmalloc for allocation
+ * and can fail unless __GFP_NOFAIL is set in @gfp_mask. This is
+ * useful for more permanant or over-sized bio allocations.
+ *
+ * RETURNS:
+ * Poitner to new bio on success, NULL on failure.
*/
struct bio *bio_kmalloc(gfp_t gfp_mask, int nr_iovecs)
{
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 14e5f42..e01e41d 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -133,6 +133,7 @@ struct bio {
* top 4 bits of bio flags indicate the pool this bio came from
*/
#define BIO_POOL_BITS (4)
+#define BIO_POOL_NONE ((1 << BIO_POOL_BITS) - 1)
#define BIO_POOL_OFFSET (BITS_PER_LONG - BIO_POOL_BITS)
#define BIO_POOL_MASK (1UL << BIO_POOL_OFFSET)
#define BIO_POOL_IDX(bio) ((bio)->bi_flags >> BIO_POOL_OFFSET)
--
1.6.0.2
--
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