Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Functions related to mapping data to requests |
| 3 | */ |
| 4 | #include <linux/kernel.h> |
| 5 | #include <linux/module.h> |
| 6 | #include <linux/bio.h> |
| 7 | #include <linux/blkdev.h> |
FUJITA Tomonori | afdc1a7 | 2008-04-11 12:56:51 +0200 | [diff] [blame] | 8 | #include <scsi/sg.h> /* for struct sg_iovec */ |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 9 | |
| 10 | #include "blk.h" |
| 11 | |
| 12 | int blk_rq_append_bio(struct request_queue *q, struct request *rq, |
| 13 | struct bio *bio) |
| 14 | { |
| 15 | if (!rq->bio) |
| 16 | blk_rq_bio_prep(q, rq, bio); |
| 17 | else if (!ll_back_merge_fn(q, rq, bio)) |
| 18 | return -EINVAL; |
| 19 | else { |
| 20 | rq->biotail->bi_next = bio; |
| 21 | rq->biotail = bio; |
| 22 | |
| 23 | rq->data_len += bio->bi_size; |
| 24 | } |
| 25 | return 0; |
| 26 | } |
| 27 | EXPORT_SYMBOL(blk_rq_append_bio); |
| 28 | |
| 29 | static int __blk_rq_unmap_user(struct bio *bio) |
| 30 | { |
| 31 | int ret = 0; |
| 32 | |
| 33 | if (bio) { |
| 34 | if (bio_flagged(bio, BIO_USER_MAPPED)) |
| 35 | bio_unmap_user(bio); |
| 36 | else |
| 37 | ret = bio_uncopy_user(bio); |
| 38 | } |
| 39 | |
| 40 | return ret; |
| 41 | } |
| 42 | |
| 43 | static int __blk_rq_map_user(struct request_queue *q, struct request *rq, |
FUJITA Tomonori | 152e283 | 2008-08-28 16:17:06 +0900 | [diff] [blame^] | 44 | struct rq_map_data *map_data, void __user *ubuf, |
| 45 | unsigned int len, gfp_t gfp_mask) |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 46 | { |
| 47 | unsigned long uaddr; |
Tejun Heo | e3790c7 | 2008-03-04 11:18:17 +0100 | [diff] [blame] | 48 | unsigned int alignment; |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 49 | struct bio *bio, *orig_bio; |
| 50 | int reading, ret; |
| 51 | |
| 52 | reading = rq_data_dir(rq) == READ; |
| 53 | |
| 54 | /* |
| 55 | * if alignment requirement is satisfied, map in user pages for |
| 56 | * direct dma. else, set up kernel bounce buffers |
| 57 | */ |
| 58 | uaddr = (unsigned long) ubuf; |
Tejun Heo | e3790c7 | 2008-03-04 11:18:17 +0100 | [diff] [blame] | 59 | alignment = queue_dma_alignment(q) | q->dma_pad_mask; |
FUJITA Tomonori | 152e283 | 2008-08-28 16:17:06 +0900 | [diff] [blame^] | 60 | if (!(uaddr & alignment) && !(len & alignment) && !map_data) |
FUJITA Tomonori | a3bce90 | 2008-08-28 16:17:05 +0900 | [diff] [blame] | 61 | bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask); |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 62 | else |
FUJITA Tomonori | 152e283 | 2008-08-28 16:17:06 +0900 | [diff] [blame^] | 63 | bio = bio_copy_user(q, map_data, uaddr, len, reading, gfp_mask); |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 64 | |
| 65 | if (IS_ERR(bio)) |
| 66 | return PTR_ERR(bio); |
| 67 | |
| 68 | orig_bio = bio; |
| 69 | blk_queue_bounce(q, &bio); |
| 70 | |
| 71 | /* |
| 72 | * We link the bounce buffer in and could have to traverse it |
| 73 | * later so we have to get a ref to prevent it from being freed |
| 74 | */ |
| 75 | bio_get(bio); |
| 76 | |
| 77 | ret = blk_rq_append_bio(q, rq, bio); |
| 78 | if (!ret) |
| 79 | return bio->bi_size; |
| 80 | |
| 81 | /* if it was boucned we must call the end io function */ |
| 82 | bio_endio(bio, 0); |
| 83 | __blk_rq_unmap_user(orig_bio); |
| 84 | bio_put(bio); |
| 85 | return ret; |
| 86 | } |
| 87 | |
| 88 | /** |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 89 | * blk_rq_map_user - map user data to a request, for REQ_TYPE_BLOCK_PC usage |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 90 | * @q: request queue where request should be inserted |
| 91 | * @rq: request structure to fill |
FUJITA Tomonori | 152e283 | 2008-08-28 16:17:06 +0900 | [diff] [blame^] | 92 | * @map_data: pointer to the rq_map_data holding pages (if necessary) |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 93 | * @ubuf: the user buffer |
| 94 | * @len: length of user data |
FUJITA Tomonori | a3bce90 | 2008-08-28 16:17:05 +0900 | [diff] [blame] | 95 | * @gfp_mask: memory allocation flags |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 96 | * |
| 97 | * Description: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 98 | * Data will be mapped directly for zero copy I/O, if possible. Otherwise |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 99 | * a kernel bounce buffer is used. |
| 100 | * |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 101 | * A matching blk_rq_unmap_user() must be issued at the end of I/O, while |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 102 | * still in process context. |
| 103 | * |
| 104 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() |
| 105 | * before being submitted to the device, as pages mapped may be out of |
| 106 | * reach. It's the callers responsibility to make sure this happens. The |
| 107 | * original bio must be passed back in to blk_rq_unmap_user() for proper |
| 108 | * unmapping. |
| 109 | */ |
| 110 | int blk_rq_map_user(struct request_queue *q, struct request *rq, |
FUJITA Tomonori | 152e283 | 2008-08-28 16:17:06 +0900 | [diff] [blame^] | 111 | struct rq_map_data *map_data, void __user *ubuf, |
| 112 | unsigned long len, gfp_t gfp_mask) |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 113 | { |
| 114 | unsigned long bytes_read = 0; |
| 115 | struct bio *bio = NULL; |
| 116 | int ret; |
| 117 | |
| 118 | if (len > (q->max_hw_sectors << 9)) |
| 119 | return -EINVAL; |
| 120 | if (!len || !ubuf) |
| 121 | return -EINVAL; |
| 122 | |
| 123 | while (bytes_read != len) { |
| 124 | unsigned long map_len, end, start; |
| 125 | |
| 126 | map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE); |
| 127 | end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1) |
| 128 | >> PAGE_SHIFT; |
| 129 | start = (unsigned long)ubuf >> PAGE_SHIFT; |
| 130 | |
| 131 | /* |
| 132 | * A bad offset could cause us to require BIO_MAX_PAGES + 1 |
| 133 | * pages. If this happens we just lower the requested |
| 134 | * mapping len by a page so that we can fit |
| 135 | */ |
| 136 | if (end - start > BIO_MAX_PAGES) |
| 137 | map_len -= PAGE_SIZE; |
| 138 | |
FUJITA Tomonori | 152e283 | 2008-08-28 16:17:06 +0900 | [diff] [blame^] | 139 | ret = __blk_rq_map_user(q, rq, map_data, ubuf, map_len, |
| 140 | gfp_mask); |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 141 | if (ret < 0) |
| 142 | goto unmap_rq; |
| 143 | if (!bio) |
| 144 | bio = rq->bio; |
| 145 | bytes_read += ret; |
| 146 | ubuf += ret; |
| 147 | } |
| 148 | |
FUJITA Tomonori | f18573a | 2008-04-11 12:56:52 +0200 | [diff] [blame] | 149 | if (!bio_flagged(bio, BIO_USER_MAPPED)) |
| 150 | rq->cmd_flags |= REQ_COPY_USER; |
Tejun Heo | 40b01b9 | 2008-02-19 11:35:38 +0100 | [diff] [blame] | 151 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 152 | rq->buffer = rq->data = NULL; |
| 153 | return 0; |
| 154 | unmap_rq: |
| 155 | blk_rq_unmap_user(bio); |
Jens Axboe | 84e9e03 | 2008-02-18 13:51:56 +0100 | [diff] [blame] | 156 | rq->bio = NULL; |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 157 | return ret; |
| 158 | } |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 159 | EXPORT_SYMBOL(blk_rq_map_user); |
| 160 | |
| 161 | /** |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 162 | * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 163 | * @q: request queue where request should be inserted |
| 164 | * @rq: request to map data to |
FUJITA Tomonori | 152e283 | 2008-08-28 16:17:06 +0900 | [diff] [blame^] | 165 | * @map_data: pointer to the rq_map_data holding pages (if necessary) |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 166 | * @iov: pointer to the iovec |
| 167 | * @iov_count: number of elements in the iovec |
| 168 | * @len: I/O byte count |
FUJITA Tomonori | a3bce90 | 2008-08-28 16:17:05 +0900 | [diff] [blame] | 169 | * @gfp_mask: memory allocation flags |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 170 | * |
| 171 | * Description: |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 172 | * Data will be mapped directly for zero copy I/O, if possible. Otherwise |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 173 | * a kernel bounce buffer is used. |
| 174 | * |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 175 | * A matching blk_rq_unmap_user() must be issued at the end of I/O, while |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 176 | * still in process context. |
| 177 | * |
| 178 | * Note: The mapped bio may need to be bounced through blk_queue_bounce() |
| 179 | * before being submitted to the device, as pages mapped may be out of |
| 180 | * reach. It's the callers responsibility to make sure this happens. The |
| 181 | * original bio must be passed back in to blk_rq_unmap_user() for proper |
| 182 | * unmapping. |
| 183 | */ |
| 184 | int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, |
FUJITA Tomonori | 152e283 | 2008-08-28 16:17:06 +0900 | [diff] [blame^] | 185 | struct rq_map_data *map_data, struct sg_iovec *iov, |
| 186 | int iov_count, unsigned int len, gfp_t gfp_mask) |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 187 | { |
| 188 | struct bio *bio; |
FUJITA Tomonori | afdc1a7 | 2008-04-11 12:56:51 +0200 | [diff] [blame] | 189 | int i, read = rq_data_dir(rq) == READ; |
| 190 | int unaligned = 0; |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 191 | |
| 192 | if (!iov || iov_count <= 0) |
| 193 | return -EINVAL; |
| 194 | |
FUJITA Tomonori | afdc1a7 | 2008-04-11 12:56:51 +0200 | [diff] [blame] | 195 | for (i = 0; i < iov_count; i++) { |
| 196 | unsigned long uaddr = (unsigned long)iov[i].iov_base; |
| 197 | |
| 198 | if (uaddr & queue_dma_alignment(q)) { |
| 199 | unaligned = 1; |
| 200 | break; |
| 201 | } |
| 202 | } |
| 203 | |
FUJITA Tomonori | 152e283 | 2008-08-28 16:17:06 +0900 | [diff] [blame^] | 204 | if (unaligned || (q->dma_pad_mask & len) || map_data) |
| 205 | bio = bio_copy_user_iov(q, map_data, iov, iov_count, read, |
| 206 | gfp_mask); |
FUJITA Tomonori | afdc1a7 | 2008-04-11 12:56:51 +0200 | [diff] [blame] | 207 | else |
FUJITA Tomonori | a3bce90 | 2008-08-28 16:17:05 +0900 | [diff] [blame] | 208 | bio = bio_map_user_iov(q, NULL, iov, iov_count, read, gfp_mask); |
FUJITA Tomonori | afdc1a7 | 2008-04-11 12:56:51 +0200 | [diff] [blame] | 209 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 210 | if (IS_ERR(bio)) |
| 211 | return PTR_ERR(bio); |
| 212 | |
| 213 | if (bio->bi_size != len) { |
| 214 | bio_endio(bio, 0); |
| 215 | bio_unmap_user(bio); |
| 216 | return -EINVAL; |
| 217 | } |
| 218 | |
FUJITA Tomonori | f18573a | 2008-04-11 12:56:52 +0200 | [diff] [blame] | 219 | if (!bio_flagged(bio, BIO_USER_MAPPED)) |
| 220 | rq->cmd_flags |= REQ_COPY_USER; |
| 221 | |
FUJITA Tomonori | 07359fc | 2008-06-26 19:39:23 +0200 | [diff] [blame] | 222 | blk_queue_bounce(q, &bio); |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 223 | bio_get(bio); |
| 224 | blk_rq_bio_prep(q, rq, bio); |
| 225 | rq->buffer = rq->data = NULL; |
| 226 | return 0; |
| 227 | } |
FUJITA Tomonori | 152e283 | 2008-08-28 16:17:06 +0900 | [diff] [blame^] | 228 | EXPORT_SYMBOL(blk_rq_map_user_iov); |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 229 | |
| 230 | /** |
| 231 | * blk_rq_unmap_user - unmap a request with user data |
| 232 | * @bio: start of bio list |
| 233 | * |
| 234 | * Description: |
| 235 | * Unmap a rq previously mapped by blk_rq_map_user(). The caller must |
| 236 | * supply the original rq->bio from the blk_rq_map_user() return, since |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 237 | * the I/O completion may have changed rq->bio. |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 238 | */ |
| 239 | int blk_rq_unmap_user(struct bio *bio) |
| 240 | { |
| 241 | struct bio *mapped_bio; |
| 242 | int ret = 0, ret2; |
| 243 | |
| 244 | while (bio) { |
| 245 | mapped_bio = bio; |
| 246 | if (unlikely(bio_flagged(bio, BIO_BOUNCED))) |
| 247 | mapped_bio = bio->bi_private; |
| 248 | |
| 249 | ret2 = __blk_rq_unmap_user(mapped_bio); |
| 250 | if (ret2 && !ret) |
| 251 | ret = ret2; |
| 252 | |
| 253 | mapped_bio = bio; |
| 254 | bio = bio->bi_next; |
| 255 | bio_put(mapped_bio); |
| 256 | } |
| 257 | |
| 258 | return ret; |
| 259 | } |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 260 | EXPORT_SYMBOL(blk_rq_unmap_user); |
| 261 | |
| 262 | /** |
Randy Dunlap | 710027a | 2008-08-19 20:13:11 +0200 | [diff] [blame] | 263 | * blk_rq_map_kern - map kernel data to a request, for REQ_TYPE_BLOCK_PC usage |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 264 | * @q: request queue where request should be inserted |
| 265 | * @rq: request to fill |
| 266 | * @kbuf: the kernel buffer |
| 267 | * @len: length of user data |
| 268 | * @gfp_mask: memory allocation flags |
FUJITA Tomonori | 68154e9 | 2008-04-25 12:47:50 +0200 | [diff] [blame] | 269 | * |
| 270 | * Description: |
| 271 | * Data will be mapped directly if possible. Otherwise a bounce |
| 272 | * buffer is used. |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 273 | */ |
| 274 | int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf, |
| 275 | unsigned int len, gfp_t gfp_mask) |
| 276 | { |
FUJITA Tomonori | 68154e9 | 2008-04-25 12:47:50 +0200 | [diff] [blame] | 277 | unsigned long kaddr; |
| 278 | unsigned int alignment; |
| 279 | int reading = rq_data_dir(rq) == READ; |
| 280 | int do_copy = 0; |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 281 | struct bio *bio; |
| 282 | |
| 283 | if (len > (q->max_hw_sectors << 9)) |
| 284 | return -EINVAL; |
| 285 | if (!len || !kbuf) |
| 286 | return -EINVAL; |
| 287 | |
FUJITA Tomonori | 68154e9 | 2008-04-25 12:47:50 +0200 | [diff] [blame] | 288 | kaddr = (unsigned long)kbuf; |
| 289 | alignment = queue_dma_alignment(q) | q->dma_pad_mask; |
FUJITA Tomonori | a76eef9 | 2008-07-25 19:44:39 -0700 | [diff] [blame] | 290 | do_copy = ((kaddr & alignment) || (len & alignment) || |
| 291 | object_is_on_stack(kbuf)); |
FUJITA Tomonori | 30c00ed | 2008-07-04 09:31:11 +0200 | [diff] [blame] | 292 | |
FUJITA Tomonori | 68154e9 | 2008-04-25 12:47:50 +0200 | [diff] [blame] | 293 | if (do_copy) |
| 294 | bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading); |
| 295 | else |
| 296 | bio = bio_map_kern(q, kbuf, len, gfp_mask); |
| 297 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 298 | if (IS_ERR(bio)) |
| 299 | return PTR_ERR(bio); |
| 300 | |
| 301 | if (rq_data_dir(rq) == WRITE) |
| 302 | bio->bi_rw |= (1 << BIO_RW); |
| 303 | |
FUJITA Tomonori | 68154e9 | 2008-04-25 12:47:50 +0200 | [diff] [blame] | 304 | if (do_copy) |
| 305 | rq->cmd_flags |= REQ_COPY_USER; |
| 306 | |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 307 | blk_rq_bio_prep(q, rq, bio); |
| 308 | blk_queue_bounce(q, &rq->bio); |
| 309 | rq->buffer = rq->data = NULL; |
| 310 | return 0; |
| 311 | } |
Jens Axboe | 86db1e2 | 2008-01-29 14:53:40 +0100 | [diff] [blame] | 312 | EXPORT_SYMBOL(blk_rq_map_kern); |