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 /fs/bio.c | |
| 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 'fs/bio.c')
| -rw-r--r-- | fs/bio.c | 24 |
1 files changed, 24 insertions, 0 deletions
@@ -263,6 +263,30 @@ void bio_init(struct bio *bio) EXPORT_SYMBOL(bio_init); /** + * bio_reset - reinitialize a bio + * @bio: bio to reset + * + * Description: + * After calling bio_reset(), @bio will be in the same state as a freshly + * allocated bio returned bio bio_alloc_bioset() - the only fields that are + * preserved are the ones that are initialized by bio_alloc_bioset(). See + * comment in struct bio. + */ +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_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 * @nr_iovecs: number of iovecs to pre-allocate |