186db1e29SJens Axboe /* 286db1e29SJens Axboe * Functions related to mapping data to requests 386db1e29SJens Axboe */ 486db1e29SJens Axboe #include <linux/kernel.h> 586db1e29SJens Axboe #include <linux/module.h> 686db1e29SJens Axboe #include <linux/bio.h> 786db1e29SJens Axboe #include <linux/blkdev.h> 886db1e29SJens Axboe 986db1e29SJens Axboe #include "blk.h" 1086db1e29SJens Axboe 1186db1e29SJens Axboe int blk_rq_append_bio(struct request_queue *q, struct request *rq, 1286db1e29SJens Axboe struct bio *bio) 1386db1e29SJens Axboe { 1486db1e29SJens Axboe if (!rq->bio) 1586db1e29SJens Axboe blk_rq_bio_prep(q, rq, bio); 1686db1e29SJens Axboe else if (!ll_back_merge_fn(q, rq, bio)) 1786db1e29SJens Axboe return -EINVAL; 1886db1e29SJens Axboe else { 1986db1e29SJens Axboe rq->biotail->bi_next = bio; 2086db1e29SJens Axboe rq->biotail = bio; 2186db1e29SJens Axboe 2286db1e29SJens Axboe rq->data_len += bio->bi_size; 2386db1e29SJens Axboe } 2486db1e29SJens Axboe return 0; 2586db1e29SJens Axboe } 2686db1e29SJens Axboe EXPORT_SYMBOL(blk_rq_append_bio); 2786db1e29SJens Axboe 2886db1e29SJens Axboe static int __blk_rq_unmap_user(struct bio *bio) 2986db1e29SJens Axboe { 3086db1e29SJens Axboe int ret = 0; 3186db1e29SJens Axboe 3286db1e29SJens Axboe if (bio) { 3386db1e29SJens Axboe if (bio_flagged(bio, BIO_USER_MAPPED)) 3486db1e29SJens Axboe bio_unmap_user(bio); 3586db1e29SJens Axboe else 3686db1e29SJens Axboe ret = bio_uncopy_user(bio); 3786db1e29SJens Axboe } 3886db1e29SJens Axboe 3986db1e29SJens Axboe return ret; 4086db1e29SJens Axboe } 4186db1e29SJens Axboe 4286db1e29SJens Axboe static int __blk_rq_map_user(struct request_queue *q, struct request *rq, 4386db1e29SJens Axboe void __user *ubuf, unsigned int len) 4486db1e29SJens Axboe { 4586db1e29SJens Axboe unsigned long uaddr; 46e3790c7dSTejun Heo unsigned int alignment; 4786db1e29SJens Axboe struct bio *bio, *orig_bio; 4886db1e29SJens Axboe int reading, ret; 4986db1e29SJens Axboe 5086db1e29SJens Axboe reading = rq_data_dir(rq) == READ; 5186db1e29SJens Axboe 5286db1e29SJens Axboe /* 5386db1e29SJens Axboe * if alignment requirement is satisfied, map in user pages for 5486db1e29SJens Axboe * direct dma. else, set up kernel bounce buffers 5586db1e29SJens Axboe */ 5686db1e29SJens Axboe uaddr = (unsigned long) ubuf; 57e3790c7dSTejun Heo alignment = queue_dma_alignment(q) | q->dma_pad_mask; 58e3790c7dSTejun Heo if (!(uaddr & alignment) && !(len & alignment)) 5986db1e29SJens Axboe bio = bio_map_user(q, NULL, uaddr, len, reading); 6086db1e29SJens Axboe else 6186db1e29SJens Axboe bio = bio_copy_user(q, uaddr, len, reading); 6286db1e29SJens Axboe 6386db1e29SJens Axboe if (IS_ERR(bio)) 6486db1e29SJens Axboe return PTR_ERR(bio); 6586db1e29SJens Axboe 6686db1e29SJens Axboe orig_bio = bio; 6786db1e29SJens Axboe blk_queue_bounce(q, &bio); 6886db1e29SJens Axboe 6986db1e29SJens Axboe /* 7086db1e29SJens Axboe * We link the bounce buffer in and could have to traverse it 7186db1e29SJens Axboe * later so we have to get a ref to prevent it from being freed 7286db1e29SJens Axboe */ 7386db1e29SJens Axboe bio_get(bio); 7486db1e29SJens Axboe 7586db1e29SJens Axboe ret = blk_rq_append_bio(q, rq, bio); 7686db1e29SJens Axboe if (!ret) 7786db1e29SJens Axboe return bio->bi_size; 7886db1e29SJens Axboe 7986db1e29SJens Axboe /* if it was boucned we must call the end io function */ 8086db1e29SJens Axboe bio_endio(bio, 0); 8186db1e29SJens Axboe __blk_rq_unmap_user(orig_bio); 8286db1e29SJens Axboe bio_put(bio); 8386db1e29SJens Axboe return ret; 8486db1e29SJens Axboe } 8586db1e29SJens Axboe 8686db1e29SJens Axboe /** 8786db1e29SJens Axboe * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage 8886db1e29SJens Axboe * @q: request queue where request should be inserted 8986db1e29SJens Axboe * @rq: request structure to fill 9086db1e29SJens Axboe * @ubuf: the user buffer 9186db1e29SJens Axboe * @len: length of user data 9286db1e29SJens Axboe * 9386db1e29SJens Axboe * Description: 9486db1e29SJens Axboe * Data will be mapped directly for zero copy io, if possible. Otherwise 9586db1e29SJens Axboe * a kernel bounce buffer is used. 9686db1e29SJens Axboe * 9786db1e29SJens Axboe * A matching blk_rq_unmap_user() must be issued at the end of io, while 9886db1e29SJens Axboe * still in process context. 9986db1e29SJens Axboe * 10086db1e29SJens Axboe * Note: The mapped bio may need to be bounced through blk_queue_bounce() 10186db1e29SJens Axboe * before being submitted to the device, as pages mapped may be out of 10286db1e29SJens Axboe * reach. It's the callers responsibility to make sure this happens. The 10386db1e29SJens Axboe * original bio must be passed back in to blk_rq_unmap_user() for proper 10486db1e29SJens Axboe * unmapping. 10586db1e29SJens Axboe */ 10686db1e29SJens Axboe int blk_rq_map_user(struct request_queue *q, struct request *rq, 10786db1e29SJens Axboe void __user *ubuf, unsigned long len) 10886db1e29SJens Axboe { 10986db1e29SJens Axboe unsigned long bytes_read = 0; 11086db1e29SJens Axboe struct bio *bio = NULL; 11186db1e29SJens Axboe int ret; 11286db1e29SJens Axboe 11386db1e29SJens Axboe if (len > (q->max_hw_sectors << 9)) 11486db1e29SJens Axboe return -EINVAL; 11586db1e29SJens Axboe if (!len || !ubuf) 11686db1e29SJens Axboe return -EINVAL; 11786db1e29SJens Axboe 11886db1e29SJens Axboe while (bytes_read != len) { 11986db1e29SJens Axboe unsigned long map_len, end, start; 12086db1e29SJens Axboe 12186db1e29SJens Axboe map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE); 12286db1e29SJens Axboe end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1) 12386db1e29SJens Axboe >> PAGE_SHIFT; 12486db1e29SJens Axboe start = (unsigned long)ubuf >> PAGE_SHIFT; 12586db1e29SJens Axboe 12686db1e29SJens Axboe /* 12786db1e29SJens Axboe * A bad offset could cause us to require BIO_MAX_PAGES + 1 12886db1e29SJens Axboe * pages. If this happens we just lower the requested 12986db1e29SJens Axboe * mapping len by a page so that we can fit 13086db1e29SJens Axboe */ 13186db1e29SJens Axboe if (end - start > BIO_MAX_PAGES) 13286db1e29SJens Axboe map_len -= PAGE_SIZE; 13386db1e29SJens Axboe 13486db1e29SJens Axboe ret = __blk_rq_map_user(q, rq, ubuf, map_len); 13586db1e29SJens Axboe if (ret < 0) 13686db1e29SJens Axboe goto unmap_rq; 13786db1e29SJens Axboe if (!bio) 13886db1e29SJens Axboe bio = rq->bio; 13986db1e29SJens Axboe bytes_read += ret; 14086db1e29SJens Axboe ubuf += ret; 14186db1e29SJens Axboe } 14286db1e29SJens Axboe 14340b01b9bSTejun Heo /* 14440b01b9bSTejun Heo * __blk_rq_map_user() copies the buffers if starting address 145e3790c7dSTejun Heo * or length isn't aligned to dma_pad_mask. As the copied 146e3790c7dSTejun Heo * buffer is always page aligned, we know that there's enough 147e3790c7dSTejun Heo * room for padding. Extend the last bio and update 148e3790c7dSTejun Heo * rq->data_len accordingly. 14940b01b9bSTejun Heo * 15040b01b9bSTejun Heo * On unmap, bio_uncopy_user() will use unmodified 15140b01b9bSTejun Heo * bio_map_data pointed to by bio->bi_private. 15240b01b9bSTejun Heo */ 153e3790c7dSTejun Heo if (len & q->dma_pad_mask) { 154e3790c7dSTejun Heo unsigned int pad_len = (q->dma_pad_mask & ~len) + 1; 15556d94a37SHarvey Harrison struct bio *tail = rq->biotail; 156e3790c7dSTejun Heo 15756d94a37SHarvey Harrison tail->bi_io_vec[tail->bi_vcnt - 1].bv_len += pad_len; 15856d94a37SHarvey Harrison tail->bi_size += pad_len; 15940b01b9bSTejun Heo 1607a85f889SFUJITA Tomonori rq->extra_len += pad_len; 16140b01b9bSTejun Heo } 16240b01b9bSTejun Heo 16386db1e29SJens Axboe rq->buffer = rq->data = NULL; 16486db1e29SJens Axboe return 0; 16586db1e29SJens Axboe unmap_rq: 16686db1e29SJens Axboe blk_rq_unmap_user(bio); 16784e9e03cSJens Axboe rq->bio = NULL; 16886db1e29SJens Axboe return ret; 16986db1e29SJens Axboe } 17086db1e29SJens Axboe EXPORT_SYMBOL(blk_rq_map_user); 17186db1e29SJens Axboe 17286db1e29SJens Axboe /** 17386db1e29SJens Axboe * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage 17486db1e29SJens Axboe * @q: request queue where request should be inserted 17586db1e29SJens Axboe * @rq: request to map data to 17686db1e29SJens Axboe * @iov: pointer to the iovec 17786db1e29SJens Axboe * @iov_count: number of elements in the iovec 17886db1e29SJens Axboe * @len: I/O byte count 17986db1e29SJens Axboe * 18086db1e29SJens Axboe * Description: 18186db1e29SJens Axboe * Data will be mapped directly for zero copy io, if possible. Otherwise 18286db1e29SJens Axboe * a kernel bounce buffer is used. 18386db1e29SJens Axboe * 18486db1e29SJens Axboe * A matching blk_rq_unmap_user() must be issued at the end of io, while 18586db1e29SJens Axboe * still in process context. 18686db1e29SJens Axboe * 18786db1e29SJens Axboe * Note: The mapped bio may need to be bounced through blk_queue_bounce() 18886db1e29SJens Axboe * before being submitted to the device, as pages mapped may be out of 18986db1e29SJens Axboe * reach. It's the callers responsibility to make sure this happens. The 19086db1e29SJens Axboe * original bio must be passed back in to blk_rq_unmap_user() for proper 19186db1e29SJens Axboe * unmapping. 19286db1e29SJens Axboe */ 19386db1e29SJens Axboe int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, 19486db1e29SJens Axboe struct sg_iovec *iov, int iov_count, unsigned int len) 19586db1e29SJens Axboe { 19686db1e29SJens Axboe struct bio *bio; 19786db1e29SJens Axboe 19886db1e29SJens Axboe if (!iov || iov_count <= 0) 19986db1e29SJens Axboe return -EINVAL; 20086db1e29SJens Axboe 20186db1e29SJens Axboe /* we don't allow misaligned data like bio_map_user() does. If the 20286db1e29SJens Axboe * user is using sg, they're expected to know the alignment constraints 20386db1e29SJens Axboe * and respect them accordingly */ 2046728cb0eSJens Axboe bio = bio_map_user_iov(q, NULL, iov, iov_count, 2056728cb0eSJens Axboe rq_data_dir(rq) == READ); 20686db1e29SJens Axboe if (IS_ERR(bio)) 20786db1e29SJens Axboe return PTR_ERR(bio); 20886db1e29SJens Axboe 20986db1e29SJens Axboe if (bio->bi_size != len) { 21086db1e29SJens Axboe bio_endio(bio, 0); 21186db1e29SJens Axboe bio_unmap_user(bio); 21286db1e29SJens Axboe return -EINVAL; 21386db1e29SJens Axboe } 21486db1e29SJens Axboe 21586db1e29SJens Axboe bio_get(bio); 21686db1e29SJens Axboe blk_rq_bio_prep(q, rq, bio); 21786db1e29SJens Axboe rq->buffer = rq->data = NULL; 21886db1e29SJens Axboe return 0; 21986db1e29SJens Axboe } 22086db1e29SJens Axboe 22186db1e29SJens Axboe /** 22286db1e29SJens Axboe * blk_rq_unmap_user - unmap a request with user data 22386db1e29SJens Axboe * @bio: start of bio list 22486db1e29SJens Axboe * 22586db1e29SJens Axboe * Description: 22686db1e29SJens Axboe * Unmap a rq previously mapped by blk_rq_map_user(). The caller must 22786db1e29SJens Axboe * supply the original rq->bio from the blk_rq_map_user() return, since 22886db1e29SJens Axboe * the io completion may have changed rq->bio. 22986db1e29SJens Axboe */ 23086db1e29SJens Axboe int blk_rq_unmap_user(struct bio *bio) 23186db1e29SJens Axboe { 23286db1e29SJens Axboe struct bio *mapped_bio; 23386db1e29SJens Axboe int ret = 0, ret2; 23486db1e29SJens Axboe 23586db1e29SJens Axboe while (bio) { 23686db1e29SJens Axboe mapped_bio = bio; 23786db1e29SJens Axboe if (unlikely(bio_flagged(bio, BIO_BOUNCED))) 23886db1e29SJens Axboe mapped_bio = bio->bi_private; 23986db1e29SJens Axboe 24086db1e29SJens Axboe ret2 = __blk_rq_unmap_user(mapped_bio); 24186db1e29SJens Axboe if (ret2 && !ret) 24286db1e29SJens Axboe ret = ret2; 24386db1e29SJens Axboe 24486db1e29SJens Axboe mapped_bio = bio; 24586db1e29SJens Axboe bio = bio->bi_next; 24686db1e29SJens Axboe bio_put(mapped_bio); 24786db1e29SJens Axboe } 24886db1e29SJens Axboe 24986db1e29SJens Axboe return ret; 25086db1e29SJens Axboe } 25186db1e29SJens Axboe EXPORT_SYMBOL(blk_rq_unmap_user); 25286db1e29SJens Axboe 25386db1e29SJens Axboe /** 25486db1e29SJens Axboe * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage 25586db1e29SJens Axboe * @q: request queue where request should be inserted 25686db1e29SJens Axboe * @rq: request to fill 25786db1e29SJens Axboe * @kbuf: the kernel buffer 25886db1e29SJens Axboe * @len: length of user data 25986db1e29SJens Axboe * @gfp_mask: memory allocation flags 26086db1e29SJens Axboe */ 26186db1e29SJens Axboe int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, 26286db1e29SJens Axboe unsigned int len, gfp_t gfp_mask) 26386db1e29SJens Axboe { 26486db1e29SJens Axboe struct bio *bio; 26586db1e29SJens Axboe 26686db1e29SJens Axboe if (len > (q->max_hw_sectors << 9)) 26786db1e29SJens Axboe return -EINVAL; 26886db1e29SJens Axboe if (!len || !kbuf) 26986db1e29SJens Axboe return -EINVAL; 27086db1e29SJens Axboe 27186db1e29SJens Axboe bio = bio_map_kern(q, kbuf, len, gfp_mask); 27286db1e29SJens Axboe if (IS_ERR(bio)) 27386db1e29SJens Axboe return PTR_ERR(bio); 27486db1e29SJens Axboe 27586db1e29SJens Axboe if (rq_data_dir(rq) == WRITE) 27686db1e29SJens Axboe bio->bi_rw |= (1 << BIO_RW); 27786db1e29SJens Axboe 27886db1e29SJens Axboe blk_rq_bio_prep(q, rq, bio); 27986db1e29SJens Axboe blk_queue_bounce(q, &rq->bio); 28086db1e29SJens Axboe rq->buffer = rq->data = NULL; 28186db1e29SJens Axboe return 0; 28286db1e29SJens Axboe } 28386db1e29SJens Axboe EXPORT_SYMBOL(blk_rq_map_kern); 284