| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20120828225337.GH1048@moria.home.lan>
Date: Tue, 28 Aug 2012 15:53:38 -0700
From: Kent Overstreet <koverstreet@...gle.com>
To: Tejun Heo <tj@...nel.org>
Cc: linux-bcache@...r.kernel.org, linux-kernel@...r.kernel.org,
dm-devel@...hat.com, vgoyal@...hat.com, mpatocka@...hat.com,
bharrosh@...asas.com, Jens Axboe <axboe@...nel.dk>
Subject: Re: [PATCH v7 3/9] block: Add bio_reset()
On Tue, Aug 28, 2012 at 03:17:15PM -0700, Kent Overstreet wrote:
> On Tue, Aug 28, 2012 at 01:31:48PM -0700, Tejun Heo wrote:
> > > + unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
> > > +
> > > + if (bio_integrity(bio))
> > > + bio_integrity_free(bio, bio->bi_pool);
> > > +
> > > + bio_disassociate_task(bio);
> >
> > Is this desirable? Why?
>
> *twitch* I should've thought more when I made that change.
>
> It occurs to me now that we specifically talked about that and decided
> to do it the other way - when I changed that I was just looking at
> bio_free() and decided they needed to be symmetrical.
>
> I still think they should be symmetrical, but if that's true bi_ioc and
> bi_css need to be moved, and also bio_disassociate_task() should be
> getting called from bio_free(), not bio_put().
Though - looking at it again I didn't actually screw anything up when I
made that change, it's just bad style.
Just screwing around a bit with the patch below, but - couple thoughts:
1) I hate duplicated code, and for the stuff in
bio_init()/bio_free()/bio_reset() it's perhaps not worth it, it is the
kind of stuff that gets out of sync.
2) It'd be better to have bio_reset() reset as much as possible, i.e. be
as close to bio_init() as posible. Fewer differences to confuse people.
diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index 7c8fe1d..a38bc7d 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -148,6 +148,9 @@ void bio_integrity_free(struct bio *bio, struct bio_set *bs)
BUG_ON(bip == NULL);
+ if (!bs)
+ bs = fs_bio_set;
+
/* 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)
diff --git a/fs/bio.c b/fs/bio.c
index c938f42..56d8fa2 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -234,39 +234,47 @@ fallback:
return bvl;
}
+static void bio_free_stuff(struct bio *bio)
+{
+ bio_disassociate_task(bio);
+
+ if (bio_integrity(bio))
+ bio_integrity_free(bio, bio->bi_pool);
+}
+
void bio_free(struct bio *bio)
{
struct bio_set *bs = bio->bi_pool;
void *p;
+ bio_free_stuff(bio);
+
if (!bs) {
- /* Bio was allocated by bio_kmalloc() */
- if (bio_integrity(bio))
- bio_integrity_free(bio, fs_bio_set);
kfree(bio);
- return;
- }
-
- if (bio_has_allocated_vec(bio))
- bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));
+ } else {
+ if (bio_has_allocated_vec(bio))
+ bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio));
- if (bio_integrity(bio))
- bio_integrity_free(bio, bs);
+ /*
+ * If we have front padding, adjust the bio pointer before freeing
+ */
+ p = bio;
+ if (bs->front_pad)
+ p -= bs->front_pad;
- /*
- * If we have front padding, adjust the bio pointer before freeing
- */
- p = bio;
- if (bs->front_pad)
- p -= bs->front_pad;
+ mempool_free(p, bs->bio_pool);
+ }
+}
- mempool_free(p, bs->bio_pool);
+static void __bio_init(struct bio *bio)
+{
+ memset(bio, 0, BIO_RESET_BYTES);
+ bio->bi_flags = 1 << BIO_UPTODATE;
}
void bio_init(struct bio *bio)
{
- memset(bio, 0, sizeof(*bio));
- bio->bi_flags = 1 << BIO_UPTODATE;
+ __bio_init(bio);
atomic_set(&bio->bi_cnt, 1);
}
EXPORT_SYMBOL(bio_init);
@@ -275,13 +283,10 @@ void bio_reset(struct bio *bio)
{
unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS);
- if (bio_integrity(bio))
- bio_integrity_free(bio, bio->bi_pool);
+ bio_free_stuff(bio);
+ __bio_init(bio);
- bio_disassociate_task(bio);
-
- memset(bio, 0, BIO_RESET_BYTES);
- bio->bi_flags = flags|(1 << BIO_UPTODATE);
+ bio->bi_flags |= flags;
}
EXPORT_SYMBOL(bio_reset);
@@ -440,10 +445,8 @@ void bio_put(struct bio *bio)
/*
* last put frees it
*/
- if (atomic_dec_and_test(&bio->bi_cnt)) {
- bio_disassociate_task(bio);
+ if (atomic_dec_and_test(&bio->bi_cnt))
bio_free(bio);
- }
}
EXPORT_SYMBOL(bio_put);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index ca63847..28bddc0 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -68,15 +68,6 @@ struct bio {
struct bvec_iter bi_iter;
- /*
- * Everything starting with bi_max_vecs will be preserved by bio_reset()
- */
-
- unsigned int bi_max_vecs; /* max bvl_vecs we can hold */
-
- atomic_t bi_cnt; /* pin count */
-
- struct bio_vec *bi_io_vec; /* the actual vec list */
#ifdef CONFIG_BLK_CGROUP
/*
* Optional ioc and css associated with this bio. Put on bio
@@ -89,6 +80,16 @@ struct bio {
struct bio_integrity_payload *bi_integrity; /* data integrity */
#endif
+ /*
+ * Everything starting with bi_max_vecs will be preserved by bio_reset()
+ */
+
+ unsigned int bi_max_vecs; /* max bvl_vecs we can hold */
+
+ atomic_t bi_cnt; /* pin count */
+
+ struct bio_vec *bi_io_vec; /* the actual vec list */
+
struct bio_set *bi_pool;
/*
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists