From 86db1e29772372155db08ff48a9ceb76e11a2ad1 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 29 Jan 2008 14:53:40 +0100 Subject: block: continue ll_rw_blk.c splitup Adds files for barrier handling, rq execution, io context handling, mapping data to requests, and queue settings. Signed-off-by: Jens Axboe --- block/blk-map.c | 264 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 264 insertions(+) create mode 100644 block/blk-map.c (limited to 'block/blk-map.c') diff --git a/block/blk-map.c b/block/blk-map.c new file mode 100644 index 0000000..916cfc9 --- /dev/null +++ b/block/blk-map.c @@ -0,0 +1,264 @@ +/* + * Functions related to mapping data to requests + */ +#include +#include +#include +#include + +#include "blk.h" + +int blk_rq_append_bio(struct request_queue *q, struct request *rq, + struct bio *bio) +{ + if (!rq->bio) + blk_rq_bio_prep(q, rq, bio); + else if (!ll_back_merge_fn(q, rq, bio)) + return -EINVAL; + else { + rq->biotail->bi_next = bio; + rq->biotail = bio; + + rq->data_len += bio->bi_size; + } + return 0; +} +EXPORT_SYMBOL(blk_rq_append_bio); + +static int __blk_rq_unmap_user(struct bio *bio) +{ + int ret = 0; + + if (bio) { + if (bio_flagged(bio, BIO_USER_MAPPED)) + bio_unmap_user(bio); + else + ret = bio_uncopy_user(bio); + } + + return ret; +} + +static int __blk_rq_map_user(struct request_queue *q, struct request *rq, + void __user *ubuf, unsigned int len) +{ + unsigned long uaddr; + struct bio *bio, *orig_bio; + int reading, ret; + + reading = rq_data_dir(rq) == READ; + + /* + * if alignment requirement is satisfied, map in user pages for + * direct dma. else, set up kernel bounce buffers + */ + uaddr = (unsigned long) ubuf; + if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q))) + bio = bio_map_user(q, NULL, uaddr, len, reading); + else + bio = bio_copy_user(q, uaddr, len, reading); + + if (IS_ERR(bio)) + return PTR_ERR(bio); + + orig_bio = bio; + blk_queue_bounce(q, &bio); + + /* + * We link the bounce buffer in and could have to traverse it + * later so we have to get a ref to prevent it from being freed + */ + bio_get(bio); + + ret = blk_rq_append_bio(q, rq, bio); + if (!ret) + return bio->bi_size; + + /* if it was boucned we must call the end io function */ + bio_endio(bio, 0); + __blk_rq_unmap_user(orig_bio); + bio_put(bio); + return ret; +} + +/** + * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage + * @q: request queue where request should be inserted + * @rq: request structure to fill + * @ubuf: the user buffer + * @len: length of user data + * + * 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(struct request_queue *q, struct request *rq, + void __user *ubuf, unsigned long len) +{ + unsigned long bytes_read = 0; + struct bio *bio = NULL; + int ret; + + if (len > (q->max_hw_sectors << 9)) + return -EINVAL; + if (!len || !ubuf) + return -EINVAL; + + while (bytes_read != len) { + unsigned long map_len, end, start; + + map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE); + end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1) + >> PAGE_SHIFT; + start = (unsigned long)ubuf >> PAGE_SHIFT; + + /* + * A bad offset could cause us to require BIO_MAX_PAGES + 1 + * pages. If this happens we just lower the requested + * mapping len by a page so that we can fit + */ + if (end - start > BIO_MAX_PAGES) + map_len -= PAGE_SIZE; + + ret = __blk_rq_map_user(q, rq, ubuf, map_len); + if (ret < 0) + goto unmap_rq; + if (!bio) + bio = rq->bio; + bytes_read += ret; + ubuf += ret; + } + + rq->buffer = rq->data = NULL; + return 0; +unmap_rq: + blk_rq_unmap_user(bio); + return ret; +} + +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 + * @len: I/O byte count + * + * 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(struct request_queue *q, struct request *rq, + struct sg_iovec *iov, int iov_count, unsigned int len) +{ + 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); + + if (bio->bi_size != len) { + bio_endio(bio, 0); + bio_unmap_user(bio); + return -EINVAL; + } + + bio_get(bio); + blk_rq_bio_prep(q, rq, bio); + rq->buffer = rq->data = NULL; + return 0; +} + +EXPORT_SYMBOL(blk_rq_map_user_iov); + +/** + * blk_rq_unmap_user - unmap a request with user data + * @bio: start of bio list + * + * Description: + * Unmap a rq previously mapped by blk_rq_map_user(). The caller must + * supply the original rq->bio from the blk_rq_map_user() return, since + * the io completion may have changed rq->bio. + */ +int blk_rq_unmap_user(struct bio *bio) +{ + struct bio *mapped_bio; + int ret = 0, ret2; + + while (bio) { + mapped_bio = bio; + if (unlikely(bio_flagged(bio, BIO_BOUNCED))) + mapped_bio = bio->bi_private; + + ret2 = __blk_rq_unmap_user(mapped_bio); + if (ret2 && !ret) + ret = ret2; + + mapped_bio = bio; + bio = bio->bi_next; + bio_put(mapped_bio); + } + + return ret; +} + +EXPORT_SYMBOL(blk_rq_unmap_user); + +/** + * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage + * @q: request queue where request should be inserted + * @rq: request to fill + * @kbuf: the kernel buffer + * @len: length of user data + * @gfp_mask: memory allocation flags + */ +int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, + unsigned int len, gfp_t gfp_mask) +{ + struct bio *bio; + + if (len > (q->max_hw_sectors << 9)) + return -EINVAL; + if (!len || !kbuf) + return -EINVAL; + + bio = bio_map_kern(q, kbuf, len, gfp_mask); + if (IS_ERR(bio)) + return PTR_ERR(bio); + + if (rq_data_dir(rq) == WRITE) + bio->bi_rw |= (1 << BIO_RW); + + blk_rq_bio_prep(q, rq, bio); + blk_queue_bounce(q, &rq->bio); + rq->buffer = rq->data = NULL; + return 0; +} + +EXPORT_SYMBOL(blk_rq_map_kern); -- cgit v1.1