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author | James Bottomley <James.Bottomley@SteelEye.com> | 2005-06-20 14:06:52 +0200 |
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committer | Jens Axboe <axboe@suse.de> | 2005-06-20 14:06:52 +0200 |
commit | f1970baf6d74e03bd32072ab453f2fc01bc1b8d3 (patch) | |
tree | 559898cdf83bd0f93b8a72248c6423a6548fb604 /drivers/block/ll_rw_blk.c | |
parent | dd1cab95f356f1395278633565f198463cf6bd24 (diff) | |
download | blackbird-op-linux-f1970baf6d74e03bd32072ab453f2fc01bc1b8d3.tar.gz blackbird-op-linux-f1970baf6d74e03bd32072ab453f2fc01bc1b8d3.zip |
[PATCH] Add scatter-gather support for the block layer SG_IO
Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'drivers/block/ll_rw_blk.c')
-rw-r--r-- | drivers/block/ll_rw_blk.c | 64 |
1 files changed, 58 insertions, 6 deletions
diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c index 42c4f3651cf8..874e46fc3748 100644 --- a/drivers/block/ll_rw_blk.c +++ b/drivers/block/ll_rw_blk.c @@ -2149,6 +2149,50 @@ int blk_rq_map_user(request_queue_t *q, struct request *rq, void __user *ubuf, EXPORT_SYMBOL(blk_rq_map_user); /** + * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage + * @q: request queue where request should be inserted + * @rq: request to map data to + * @iov: pointer to the iovec + * @iov_count: number of elements in the iovec + * + * Description: + * Data will be mapped directly for zero copy io, if possible. Otherwise + * a kernel bounce buffer is used. + * + * A matching blk_rq_unmap_user() must be issued at the end of io, while + * still in process context. + * + * Note: The mapped bio may need to be bounced through blk_queue_bounce() + * before being submitted to the device, as pages mapped may be out of + * reach. It's the callers responsibility to make sure this happens. The + * original bio must be passed back in to blk_rq_unmap_user() for proper + * unmapping. + */ +int blk_rq_map_user_iov(request_queue_t *q, struct request *rq, + struct sg_iovec *iov, int iov_count) +{ + struct bio *bio; + + if (!iov || iov_count <= 0) + return -EINVAL; + + /* we don't allow misaligned data like bio_map_user() does. If the + * user is using sg, they're expected to know the alignment constraints + * and respect them accordingly */ + bio = bio_map_user_iov(q, NULL, iov, iov_count, rq_data_dir(rq)== READ); + if (IS_ERR(bio)) + return PTR_ERR(bio); + + rq->bio = rq->biotail = bio; + blk_rq_bio_prep(q, rq, bio); + rq->buffer = rq->data = NULL; + rq->data_len = bio->bi_size; + return 0; +} + +EXPORT_SYMBOL(blk_rq_map_user_iov); + +/** * blk_rq_unmap_user - unmap a request with user data * @rq: request to be unmapped * @bio: bio for the request @@ -2207,6 +2251,19 @@ int blk_rq_map_kern(request_queue_t *q, struct request *rq, void *kbuf, EXPORT_SYMBOL(blk_rq_map_kern); +void blk_execute_rq_nowait(request_queue_t *q, struct gendisk *bd_disk, + struct request *rq, int at_head, + void (*done)(struct request *)) +{ + int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK; + + rq->rq_disk = bd_disk; + rq->flags |= REQ_NOMERGE; + rq->end_io = done; + elv_add_request(q, rq, where, 1); + generic_unplug_device(q); +} + /** * blk_execute_rq - insert a request into queue for execution * @q: queue to insert the request in @@ -2224,8 +2281,6 @@ int blk_execute_rq(request_queue_t *q, struct gendisk *bd_disk, char sense[SCSI_SENSE_BUFFERSIZE]; int err = 0; - rq->rq_disk = bd_disk; - /* * we need an extra reference to the request, so we can look at * it after io completion @@ -2238,11 +2293,8 @@ int blk_execute_rq(request_queue_t *q, struct gendisk *bd_disk, rq->sense_len = 0; } - rq->flags |= REQ_NOMERGE; rq->waiting = &wait; - rq->end_io = blk_end_sync_rq; - elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 1); - generic_unplug_device(q); + blk_execute_rq_nowait(q, bd_disk, rq, 0, blk_end_sync_rq); wait_for_completion(&wait); rq->waiting = NULL; |