diff options
| author | Kent Overstreet <koverstreet@google.com> | 2012-09-06 15:34:58 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2012-09-09 10:35:39 +0200 |
| commit | f44b48c7691be7643877d1f881b5eeace654d05d (patch) | |
| tree | a862b4844b99abfa1bfb6fd437cf1ee4f055c438 /include | |
| parent | 94818742316e27d01506240cf8b07d69844d31af (diff) | |
block: Add bio_reset()
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.
This required reordering struct bio, but the block layer is not yet
nearly fast enough for any cacheline effects to matter here.
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
v9: Add a function comment
Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/bio.h | 1 | ||||
| -rw-r--r-- | include/linux/blk_types.h | 25 |
2 files changed, 20 insertions, 6 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h index a11f74bc82d2..76f6c252baff 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 af9dd9d2efc4..1b607c247d72 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -59,12 +59,6 @@ struct bio { unsigned int bi_seg_front_size; unsigned int bi_seg_back_size; - 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; @@ -80,6 +74,16 @@ 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 */ + /* If bi_pool is non NULL, bi_destructor is not called */ struct bio_set *bi_pool; @@ -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))) /* |