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author | Christoph Hellwig <hch@lst.de> | 2010-06-18 16:59:42 +0200 |
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committer | Jens Axboe <jaxboe@fusionio.com> | 2010-08-07 18:23:08 +0200 |
commit | 66ac0280197981f88774e74b60c8e5f9f07c1dba (patch) | |
tree | d093ce493146779926df88b5831805c6f9ee14e1 /block/blk-core.c | |
parent | 082439004b31adc146e96e5f1c574dd2b57dcd93 (diff) | |
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block: don't allocate a payload for discard request
Allocating a fixed payload for discard requests always was a horrible hack,
and it's not coming to byte us when adding support for discard in DM/MD.
So change the code to leave the allocation of a payload to the lowlevel
driver. Unfortunately that means we'll need another hack, which allows
us to update the various block layer length fields indicating that we
have a payload. Instead of hiding this in sd.c, which we already partially
do for UNMAP support add a documented helper in the core block layer for it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'block/blk-core.c')
-rw-r--r-- | block/blk-core.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 66c3cfe..3531d8e 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1135,6 +1135,38 @@ void blk_put_request(struct request *req) } EXPORT_SYMBOL(blk_put_request); +/** + * blk_add_request_payload - add a payload to a request + * @rq: request to update + * @page: page backing the payload + * @len: length of the payload. + * + * This allows to later add a payload to an already submitted request by + * a block driver. The driver needs to take care of freeing the payload + * itself. + * + * Note that this is a quite horrible hack and nothing but handling of + * discard requests should ever use it. + */ +void blk_add_request_payload(struct request *rq, struct page *page, + unsigned int len) +{ + struct bio *bio = rq->bio; + + bio->bi_io_vec->bv_page = page; + bio->bi_io_vec->bv_offset = 0; + bio->bi_io_vec->bv_len = len; + + bio->bi_size = len; + bio->bi_vcnt = 1; + bio->bi_phys_segments = 1; + + rq->__data_len = rq->resid_len = len; + rq->nr_phys_segments = 1; + rq->buffer = bio_data(bio); +} +EXPORT_SYMBOL_GPL(blk_add_request_payload); + void init_request_from_bio(struct request *req, struct bio *bio) { req->cpu = bio->bi_comp_cpu; |