| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Functions related to mapping data to requests |
| */ |
| #include <linux/kernel.h> |
| #include <linux/sched/task_stack.h> |
| #include <linux/module.h> |
| #include <linux/bio.h> |
| #include <linux/blkdev.h> |
| #include <linux/uio.h> |
| |
| #include "blk.h" |
| |
| /* |
| * Append a bio to a passthrough request. Only works if the bio can be merged |
| * into the request based on the driver constraints. |
| */ |
| int blk_rq_append_bio(struct request *rq, struct bio **bio) |
| { |
| struct bio *orig_bio = *bio; |
| |
| blk_queue_bounce(rq->q, bio); |
| |
| if (!rq->bio) { |
| blk_rq_bio_prep(rq->q, rq, *bio); |
| } else { |
| if (!ll_back_merge_fn(rq->q, rq, *bio)) { |
| if (orig_bio != *bio) { |
| bio_put(*bio); |
| *bio = orig_bio; |
| } |
| return -EINVAL; |
| } |
| |
| rq->biotail->bi_next = *bio; |
| rq->biotail = *bio; |
| rq->__data_len += (*bio)->bi_iter.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_iov(struct request *rq, |
| struct rq_map_data *map_data, struct iov_iter *iter, |
| gfp_t gfp_mask, bool copy) |
| { |
| struct request_queue *q = rq->q; |
| struct bio *bio, *orig_bio; |
| int ret; |
| |
| if (copy) |
| bio = bio_copy_user_iov(q, map_data, iter, gfp_mask); |
| else |
| bio = bio_map_user_iov(q, iter, gfp_mask); |
| |
| if (IS_ERR(bio)) |
| return PTR_ERR(bio); |
| |
| bio->bi_opf &= ~REQ_OP_MASK; |
| bio->bi_opf |= req_op(rq); |
| |
| if (map_data && map_data->null_mapped) |
| bio_set_flag(bio, BIO_NULL_MAPPED); |
| |
| iov_iter_advance(iter, bio->bi_iter.bi_size); |
| if (map_data) |
| map_data->offset += bio->bi_iter.bi_size; |
| |
| orig_bio = 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 |
| */ |
| ret = blk_rq_append_bio(rq, &bio); |
| if (ret) { |
| __blk_rq_unmap_user(orig_bio); |
| return ret; |
| } |
| bio_get(bio); |
| |
| return 0; |
| } |
| |
| /** |
| * blk_rq_map_user_iov - map user data to a request, for passthrough requests |
| * @q: request queue where request should be inserted |
| * @rq: request to map data to |
| * @map_data: pointer to the rq_map_data holding pages (if necessary) |
| * @iter: iovec iterator |
| * @gfp_mask: memory allocation flags |
| * |
| * Description: |
| * Data will be mapped directly for zero copy I/O, if possible. Otherwise |
| * a kernel bounce buffer is used. |
| * |
| * A matching blk_rq_unmap_user() must be issued at the end of I/O, 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 rq_map_data *map_data, |
| const struct iov_iter *iter, gfp_t gfp_mask) |
| { |
| bool copy = false; |
| unsigned long align = q->dma_pad_mask | queue_dma_alignment(q); |
| struct bio *bio = NULL; |
| struct iov_iter i; |
| int ret; |
| |
| if (!iter_is_iovec(iter)) |
| goto fail; |
| |
| if (map_data) |
| copy = true; |
| else if (iov_iter_alignment(iter) & align) |
| copy = true; |
| else if (queue_virt_boundary(q)) |
| copy = queue_virt_boundary(q) & iov_iter_gap_alignment(iter); |
| |
| i = *iter; |
| do { |
| ret =__blk_rq_map_user_iov(rq, map_data, &i, gfp_mask, copy); |
| if (ret) |
| goto unmap_rq; |
| if (!bio) |
| bio = rq->bio; |
| } while (iov_iter_count(&i)); |
| |
| if (!bio_flagged(bio, BIO_USER_MAPPED)) |
| rq->rq_flags |= RQF_COPY_USER; |
| return 0; |
| |
| unmap_rq: |
| __blk_rq_unmap_user(bio); |
| fail: |
| rq->bio = NULL; |
| return -EINVAL; |
| } |
| EXPORT_SYMBOL(blk_rq_map_user_iov); |
| |
| int blk_rq_map_user(struct request_queue *q, struct request *rq, |
| struct rq_map_data *map_data, void __user *ubuf, |
| unsigned long len, gfp_t gfp_mask) |
| { |
| struct iovec iov; |
| struct iov_iter i; |
| int ret = import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i); |
| |
| if (unlikely(ret < 0)) |
| return ret; |
| |
| return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask); |
| } |
| EXPORT_SYMBOL(blk_rq_map_user); |
| |
| /** |
| * 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 I/O 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 passthrough requests |
| * @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 |
| * |
| * Description: |
| * Data will be mapped directly if possible. Otherwise a bounce |
| * buffer is used. Can be called multiple times to append multiple |
| * buffers. |
| */ |
| int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, |
| unsigned int len, gfp_t gfp_mask) |
| { |
| int reading = rq_data_dir(rq) == READ; |
| unsigned long addr = (unsigned long) kbuf; |
| int do_copy = 0; |
| struct bio *bio, *orig_bio; |
| int ret; |
| |
| if (len > (queue_max_hw_sectors(q) << 9)) |
| return -EINVAL; |
| if (!len || !kbuf) |
| return -EINVAL; |
| |
| do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf); |
| if (do_copy) |
| bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading); |
| else |
| bio = bio_map_kern(q, kbuf, len, gfp_mask); |
| |
| if (IS_ERR(bio)) |
| return PTR_ERR(bio); |
| |
| bio->bi_opf &= ~REQ_OP_MASK; |
| bio->bi_opf |= req_op(rq); |
| |
| if (do_copy) |
| rq->rq_flags |= RQF_COPY_USER; |
| |
| orig_bio = bio; |
| ret = blk_rq_append_bio(rq, &bio); |
| if (unlikely(ret)) { |
| /* request is too big */ |
| bio_put(orig_bio); |
| return ret; |
| } |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(blk_rq_map_kern); |