2 * Functions related to mapping data to requests
4 #include <linux/kernel.h>
5 #include <linux/module.h>
7 #include <linux/blkdev.h>
12 static bool iovec_gap_to_prv(struct request_queue *q,
13 struct iovec *prv, struct iovec *cur)
15 unsigned long prev_end;
17 if (!queue_virt_boundary(q))
20 if (prv->iov_base == NULL && prv->iov_len == 0)
21 /* prv is not set - don't check */
24 prev_end = (unsigned long)(prv->iov_base + prv->iov_len);
26 return (((unsigned long)cur->iov_base & queue_virt_boundary(q)) ||
27 prev_end & queue_virt_boundary(q));
30 int blk_rq_append_bio(struct request_queue *q, struct request *rq,
34 blk_rq_bio_prep(q, rq, bio);
35 else if (!ll_back_merge_fn(q, rq, bio))
38 rq->biotail->bi_next = bio;
41 rq->__data_len += bio->bi_iter.bi_size;
46 static int __blk_rq_unmap_user(struct bio *bio)
51 if (bio_flagged(bio, BIO_USER_MAPPED))
54 ret = bio_uncopy_user(bio);
60 static int __blk_rq_map_user_iov(struct request *rq,
61 struct rq_map_data *map_data, struct iov_iter *iter,
62 gfp_t gfp_mask, bool copy)
64 struct request_queue *q = rq->q;
65 struct bio *bio, *orig_bio;
69 bio = bio_copy_user_iov(q, map_data, iter, gfp_mask);
71 bio = bio_map_user_iov(q, iter, gfp_mask);
76 if (map_data && map_data->null_mapped)
77 bio_set_flag(bio, BIO_NULL_MAPPED);
79 iov_iter_advance(iter, bio->bi_iter.bi_size);
81 map_data->offset += bio->bi_iter.bi_size;
84 blk_queue_bounce(q, &bio);
87 * We link the bounce buffer in and could have to traverse it
88 * later so we have to get a ref to prevent it from being freed
92 ret = blk_rq_append_bio(q, rq, bio);
95 __blk_rq_unmap_user(orig_bio);
104 * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage
105 * @q: request queue where request should be inserted
106 * @rq: request to map data to
107 * @map_data: pointer to the rq_map_data holding pages (if necessary)
108 * @iter: iovec iterator
109 * @gfp_mask: memory allocation flags
112 * Data will be mapped directly for zero copy I/O, if possible. Otherwise
113 * a kernel bounce buffer is used.
115 * A matching blk_rq_unmap_user() must be issued at the end of I/O, while
116 * still in process context.
118 * Note: The mapped bio may need to be bounced through blk_queue_bounce()
119 * before being submitted to the device, as pages mapped may be out of
120 * reach. It's the callers responsibility to make sure this happens. The
121 * original bio must be passed back in to blk_rq_unmap_user() for proper
124 int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
125 struct rq_map_data *map_data,
126 const struct iov_iter *iter, gfp_t gfp_mask)
128 struct iovec iov, prv = {.iov_base = NULL, .iov_len = 0};
129 bool copy = (q->dma_pad_mask & iter->count) || map_data;
130 struct bio *bio = NULL;
134 if (!iter || !iter->count)
137 iov_for_each(iov, i, *iter) {
138 unsigned long uaddr = (unsigned long) iov.iov_base;
144 * Keep going so we check length of all segments
146 if ((uaddr & queue_dma_alignment(q)) ||
147 iovec_gap_to_prv(q, &prv, &iov))
150 prv.iov_base = iov.iov_base;
151 prv.iov_len = iov.iov_len;
156 ret =__blk_rq_map_user_iov(rq, map_data, &i, gfp_mask, copy);
161 } while (iov_iter_count(&i));
163 if (!bio_flagged(bio, BIO_USER_MAPPED))
164 rq->cmd_flags |= REQ_COPY_USER;
168 __blk_rq_unmap_user(bio);
172 EXPORT_SYMBOL(blk_rq_map_user_iov);
174 int blk_rq_map_user(struct request_queue *q, struct request *rq,
175 struct rq_map_data *map_data, void __user *ubuf,
176 unsigned long len, gfp_t gfp_mask)
180 int ret = import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i);
182 if (unlikely(ret < 0))
185 return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask);
187 EXPORT_SYMBOL(blk_rq_map_user);
190 * blk_rq_unmap_user - unmap a request with user data
191 * @bio: start of bio list
194 * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
195 * supply the original rq->bio from the blk_rq_map_user() return, since
196 * the I/O completion may have changed rq->bio.
198 int blk_rq_unmap_user(struct bio *bio)
200 struct bio *mapped_bio;
205 if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
206 mapped_bio = bio->bi_private;
208 ret2 = __blk_rq_unmap_user(mapped_bio);
219 EXPORT_SYMBOL(blk_rq_unmap_user);
222 * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage
223 * @q: request queue where request should be inserted
224 * @rq: request to fill
225 * @kbuf: the kernel buffer
226 * @len: length of user data
227 * @gfp_mask: memory allocation flags
230 * Data will be mapped directly if possible. Otherwise a bounce
231 * buffer is used. Can be called multiple times to append multiple
234 int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
235 unsigned int len, gfp_t gfp_mask)
237 int reading = rq_data_dir(rq) == READ;
238 unsigned long addr = (unsigned long) kbuf;
243 if (len > (queue_max_hw_sectors(q) << 9))
248 do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf);
250 bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
252 bio = bio_map_kern(q, kbuf, len, gfp_mask);
258 bio->bi_rw |= REQ_WRITE;
261 rq->cmd_flags |= REQ_COPY_USER;
263 ret = blk_rq_append_bio(q, rq, bio);
265 /* request is too big */
270 blk_queue_bounce(q, &rq->bio);
273 EXPORT_SYMBOL(blk_rq_map_kern);