[PATCH v7 3/9] block: Add bio_reset()
From: Kent Overstreet <hidden>
Date: 2012-08-28 17:39:42
Also in:
dm-devel, lkml
Subsystem:
block layer, filesystems (vfs and infrastructure), the rest · Maintainers:
Jens Axboe, Alexander Viro, Christian Brauner, Linus Torvalds
Reusing bios is something that's been highly frowned upon in the past, but driver code keeps doing it anyways. If it's going to happen anyways, we should provide a generic method. This'll help with getting rid of bi_destructor - drivers/block/pktcdvd.c was open coding it, by doing a bio_init() and resetting bi_destructor. v5: Add a define BIO_RESET_BITS, to be very explicit about what parts of bio->bi_flags are saved. v6: Further commenting verbosity, per Tejun Signed-off-by: Kent Overstreet <redacted> CC: Jens Axboe <axboe@kernel.dk> Acked-by: Tejun Heo <tj@kernel.org> --- fs/bio.c | 14 ++++++++++++++ include/linux/bio.h | 1 + include/linux/blk_types.h | 21 +++++++++++++++++---- 3 files changed, 32 insertions(+), 4 deletions(-)
diff --git a/fs/bio.c b/fs/bio.c
index e017f7a..52da084 100644
--- a/fs/bio.c
+++ b/fs/bio.c@@ -262,6 +262,20 @@ void bio_init(struct bio *bio) } EXPORT_SYMBOL(bio_init); +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_disassociate_task(bio); + + memset(bio, 0, BIO_RESET_BYTES); + bio->bi_flags = flags|(1 << BIO_UPTODATE); +} +EXPORT_SYMBOL(bio_reset); + /** * bio_alloc_bioset - allocate a bio for I/O * @gfp_mask: the GFP_ mask given to the slab allocator
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 2643589..ba60319 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h@@ -226,6 +226,7 @@ extern void __bio_clone(struct bio *, struct bio *); extern struct bio *bio_clone(struct bio *, gfp_t); extern void bio_init(struct bio *); +extern void bio_reset(struct bio *); extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int); extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index af9dd9d..691edd1 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h@@ -59,15 +59,19 @@ struct bio { unsigned int bi_seg_front_size; unsigned int bi_seg_back_size; + bio_end_io_t *bi_end_io; + + void *bi_private; + + /* + * 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 */ - - bio_end_io_t *bi_end_io; - - void *bi_private; #ifdef CONFIG_BLK_CGROUP /* * Optional ioc and css associated with this bio. Put on bio
@@ -93,6 +97,8 @@ struct bio { struct bio_vec bi_inline_vecs[0]; }; +#define BIO_RESET_BYTES offsetof(struct bio, bi_max_vecs) + /* * bio flags */
@@ -108,6 +114,13 @@ struct bio { #define BIO_FS_INTEGRITY 9 /* fs owns integrity data, not block layer */ #define BIO_QUIET 10 /* Make BIO Quiet */ #define BIO_MAPPED_INTEGRITY 11/* integrity metadata has been remapped */ + +/* + * Flags starting here get preserved by bio_reset() - this includes + * BIO_POOL_IDX() + */ +#define BIO_RESET_BITS 12 + #define bio_flagged(bio, flag) ((bio)->bi_flags & (1 << (flag))) /*
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1.7.12