1 /*
2 * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses. You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 * Redistribution and use in source and binary forms, with or
11 * without modification, are permitted provided that the following
12 * conditions are met:
13 *
14 * - Redistributions of source code must retain the above
15 * copyright notice, this list of conditions and the following
16 * disclaimer.
17 *
18 * - Redistributions in binary form must reproduce the above
19 * copyright notice, this list of conditions and the following
20 * disclaimer in the documentation and/or other materials
21 * provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 */
32 #include <linux/module.h>
33 #include <linux/kernel.h>
34 #include <linux/slab.h>
35 #include <linux/mm.h>
36 #include <linux/highmem.h>
37 #include <linux/scatterlist.h>
38
39 #include "iscsi_iser.h"
40
41 #define ISER_KMALLOC_THRESHOLD 0x20000 /* 128K - kmalloc limit */
42
43 /**
44 * iser_start_rdma_unaligned_sg
45 */
iser_start_rdma_unaligned_sg(struct iscsi_iser_task * iser_task,enum iser_data_dir cmd_dir)46 static int iser_start_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
47 enum iser_data_dir cmd_dir)
48 {
49 int dma_nents;
50 struct ib_device *dev;
51 char *mem = NULL;
52 struct iser_data_buf *data = &iser_task->data[cmd_dir];
53 unsigned long cmd_data_len = data->data_len;
54
55 if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
56 mem = (void *)__get_free_pages(GFP_ATOMIC,
57 ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
58 else
59 mem = kmalloc(cmd_data_len, GFP_ATOMIC);
60
61 if (mem == NULL) {
62 iser_err("Failed to allocate mem size %d %d for copying sglist\n",
63 data->size,(int)cmd_data_len);
64 return -ENOMEM;
65 }
66
67 if (cmd_dir == ISER_DIR_OUT) {
68 /* copy the unaligned sg the buffer which is used for RDMA */
69 struct scatterlist *sgl = (struct scatterlist *)data->buf;
70 struct scatterlist *sg;
71 int i;
72 char *p, *from;
73
74 p = mem;
75 for_each_sg(sgl, sg, data->size, i) {
76 from = kmap_atomic(sg_page(sg));
77 memcpy(p,
78 from + sg->offset,
79 sg->length);
80 kunmap_atomic(from);
81 p += sg->length;
82 }
83 }
84
85 sg_init_one(&iser_task->data_copy[cmd_dir].sg_single, mem, cmd_data_len);
86 iser_task->data_copy[cmd_dir].buf =
87 &iser_task->data_copy[cmd_dir].sg_single;
88 iser_task->data_copy[cmd_dir].size = 1;
89
90 iser_task->data_copy[cmd_dir].copy_buf = mem;
91
92 dev = iser_task->iser_conn->ib_conn->device->ib_device;
93 dma_nents = ib_dma_map_sg(dev,
94 &iser_task->data_copy[cmd_dir].sg_single,
95 1,
96 (cmd_dir == ISER_DIR_OUT) ?
97 DMA_TO_DEVICE : DMA_FROM_DEVICE);
98 BUG_ON(dma_nents == 0);
99
100 iser_task->data_copy[cmd_dir].dma_nents = dma_nents;
101 return 0;
102 }
103
104 /**
105 * iser_finalize_rdma_unaligned_sg
106 */
iser_finalize_rdma_unaligned_sg(struct iscsi_iser_task * iser_task,enum iser_data_dir cmd_dir)107 void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
108 enum iser_data_dir cmd_dir)
109 {
110 struct ib_device *dev;
111 struct iser_data_buf *mem_copy;
112 unsigned long cmd_data_len;
113
114 dev = iser_task->iser_conn->ib_conn->device->ib_device;
115 mem_copy = &iser_task->data_copy[cmd_dir];
116
117 ib_dma_unmap_sg(dev, &mem_copy->sg_single, 1,
118 (cmd_dir == ISER_DIR_OUT) ?
119 DMA_TO_DEVICE : DMA_FROM_DEVICE);
120
121 if (cmd_dir == ISER_DIR_IN) {
122 char *mem;
123 struct scatterlist *sgl, *sg;
124 unsigned char *p, *to;
125 unsigned int sg_size;
126 int i;
127
128 /* copy back read RDMA to unaligned sg */
129 mem = mem_copy->copy_buf;
130
131 sgl = (struct scatterlist *)iser_task->data[ISER_DIR_IN].buf;
132 sg_size = iser_task->data[ISER_DIR_IN].size;
133
134 p = mem;
135 for_each_sg(sgl, sg, sg_size, i) {
136 to = kmap_atomic(sg_page(sg));
137 memcpy(to + sg->offset,
138 p,
139 sg->length);
140 kunmap_atomic(to);
141 p += sg->length;
142 }
143 }
144
145 cmd_data_len = iser_task->data[cmd_dir].data_len;
146
147 if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
148 free_pages((unsigned long)mem_copy->copy_buf,
149 ilog2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
150 else
151 kfree(mem_copy->copy_buf);
152
153 mem_copy->copy_buf = NULL;
154 }
155
156 #define IS_4K_ALIGNED(addr) ((((unsigned long)addr) & ~MASK_4K) == 0)
157
158 /**
159 * iser_sg_to_page_vec - Translates scatterlist entries to physical addresses
160 * and returns the length of resulting physical address array (may be less than
161 * the original due to possible compaction).
162 *
163 * we build a "page vec" under the assumption that the SG meets the RDMA
164 * alignment requirements. Other then the first and last SG elements, all
165 * the "internal" elements can be compacted into a list whose elements are
166 * dma addresses of physical pages. The code supports also the weird case
167 * where --few fragments of the same page-- are present in the SG as
168 * consecutive elements. Also, it handles one entry SG.
169 */
170
iser_sg_to_page_vec(struct iser_data_buf * data,struct iser_page_vec * page_vec,struct ib_device * ibdev)171 static int iser_sg_to_page_vec(struct iser_data_buf *data,
172 struct iser_page_vec *page_vec,
173 struct ib_device *ibdev)
174 {
175 struct scatterlist *sg, *sgl = (struct scatterlist *)data->buf;
176 u64 start_addr, end_addr, page, chunk_start = 0;
177 unsigned long total_sz = 0;
178 unsigned int dma_len;
179 int i, new_chunk, cur_page, last_ent = data->dma_nents - 1;
180
181 /* compute the offset of first element */
182 page_vec->offset = (u64) sgl[0].offset & ~MASK_4K;
183
184 new_chunk = 1;
185 cur_page = 0;
186 for_each_sg(sgl, sg, data->dma_nents, i) {
187 start_addr = ib_sg_dma_address(ibdev, sg);
188 if (new_chunk)
189 chunk_start = start_addr;
190 dma_len = ib_sg_dma_len(ibdev, sg);
191 end_addr = start_addr + dma_len;
192 total_sz += dma_len;
193
194 /* collect page fragments until aligned or end of SG list */
195 if (!IS_4K_ALIGNED(end_addr) && i < last_ent) {
196 new_chunk = 0;
197 continue;
198 }
199 new_chunk = 1;
200
201 /* address of the first page in the contiguous chunk;
202 masking relevant for the very first SG entry,
203 which might be unaligned */
204 page = chunk_start & MASK_4K;
205 do {
206 page_vec->pages[cur_page++] = page;
207 page += SIZE_4K;
208 } while (page < end_addr);
209 }
210
211 page_vec->data_size = total_sz;
212 iser_dbg("page_vec->data_size:%d cur_page %d\n", page_vec->data_size,cur_page);
213 return cur_page;
214 }
215
216
217 /**
218 * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
219 * for RDMA sub-list of a scatter-gather list of memory buffers, and returns
220 * the number of entries which are aligned correctly. Supports the case where
221 * consecutive SG elements are actually fragments of the same physcial page.
222 */
iser_data_buf_aligned_len(struct iser_data_buf * data,struct ib_device * ibdev)223 static int iser_data_buf_aligned_len(struct iser_data_buf *data,
224 struct ib_device *ibdev)
225 {
226 struct scatterlist *sgl, *sg, *next_sg = NULL;
227 u64 start_addr, end_addr;
228 int i, ret_len, start_check = 0;
229
230 if (data->dma_nents == 1)
231 return 1;
232
233 sgl = (struct scatterlist *)data->buf;
234 start_addr = ib_sg_dma_address(ibdev, sgl);
235
236 for_each_sg(sgl, sg, data->dma_nents, i) {
237 if (start_check && !IS_4K_ALIGNED(start_addr))
238 break;
239
240 next_sg = sg_next(sg);
241 if (!next_sg)
242 break;
243
244 end_addr = start_addr + ib_sg_dma_len(ibdev, sg);
245 start_addr = ib_sg_dma_address(ibdev, next_sg);
246
247 if (end_addr == start_addr) {
248 start_check = 0;
249 continue;
250 } else
251 start_check = 1;
252
253 if (!IS_4K_ALIGNED(end_addr))
254 break;
255 }
256 ret_len = (next_sg) ? i : i+1;
257 iser_dbg("Found %d aligned entries out of %d in sg:0x%p\n",
258 ret_len, data->dma_nents, data);
259 return ret_len;
260 }
261
iser_data_buf_dump(struct iser_data_buf * data,struct ib_device * ibdev)262 static void iser_data_buf_dump(struct iser_data_buf *data,
263 struct ib_device *ibdev)
264 {
265 struct scatterlist *sgl = (struct scatterlist *)data->buf;
266 struct scatterlist *sg;
267 int i;
268
269 if (iser_debug_level == 0)
270 return;
271
272 for_each_sg(sgl, sg, data->dma_nents, i)
273 iser_warn("sg[%d] dma_addr:0x%lX page:0x%p "
274 "off:0x%x sz:0x%x dma_len:0x%x\n",
275 i, (unsigned long)ib_sg_dma_address(ibdev, sg),
276 sg_page(sg), sg->offset,
277 sg->length, ib_sg_dma_len(ibdev, sg));
278 }
279
iser_dump_page_vec(struct iser_page_vec * page_vec)280 static void iser_dump_page_vec(struct iser_page_vec *page_vec)
281 {
282 int i;
283
284 iser_err("page vec length %d data size %d\n",
285 page_vec->length, page_vec->data_size);
286 for (i = 0; i < page_vec->length; i++)
287 iser_err("%d %lx\n",i,(unsigned long)page_vec->pages[i]);
288 }
289
iser_page_vec_build(struct iser_data_buf * data,struct iser_page_vec * page_vec,struct ib_device * ibdev)290 static void iser_page_vec_build(struct iser_data_buf *data,
291 struct iser_page_vec *page_vec,
292 struct ib_device *ibdev)
293 {
294 int page_vec_len = 0;
295
296 page_vec->length = 0;
297 page_vec->offset = 0;
298
299 iser_dbg("Translating sg sz: %d\n", data->dma_nents);
300 page_vec_len = iser_sg_to_page_vec(data, page_vec, ibdev);
301 iser_dbg("sg len %d page_vec_len %d\n", data->dma_nents,page_vec_len);
302
303 page_vec->length = page_vec_len;
304
305 if (page_vec_len * SIZE_4K < page_vec->data_size) {
306 iser_err("page_vec too short to hold this SG\n");
307 iser_data_buf_dump(data, ibdev);
308 iser_dump_page_vec(page_vec);
309 BUG();
310 }
311 }
312
iser_dma_map_task_data(struct iscsi_iser_task * iser_task,struct iser_data_buf * data,enum iser_data_dir iser_dir,enum dma_data_direction dma_dir)313 int iser_dma_map_task_data(struct iscsi_iser_task *iser_task,
314 struct iser_data_buf *data,
315 enum iser_data_dir iser_dir,
316 enum dma_data_direction dma_dir)
317 {
318 struct ib_device *dev;
319
320 iser_task->dir[iser_dir] = 1;
321 dev = iser_task->iser_conn->ib_conn->device->ib_device;
322
323 data->dma_nents = ib_dma_map_sg(dev, data->buf, data->size, dma_dir);
324 if (data->dma_nents == 0) {
325 iser_err("dma_map_sg failed!!!\n");
326 return -EINVAL;
327 }
328 return 0;
329 }
330
iser_dma_unmap_task_data(struct iscsi_iser_task * iser_task)331 void iser_dma_unmap_task_data(struct iscsi_iser_task *iser_task)
332 {
333 struct ib_device *dev;
334 struct iser_data_buf *data;
335
336 dev = iser_task->iser_conn->ib_conn->device->ib_device;
337
338 if (iser_task->dir[ISER_DIR_IN]) {
339 data = &iser_task->data[ISER_DIR_IN];
340 ib_dma_unmap_sg(dev, data->buf, data->size, DMA_FROM_DEVICE);
341 }
342
343 if (iser_task->dir[ISER_DIR_OUT]) {
344 data = &iser_task->data[ISER_DIR_OUT];
345 ib_dma_unmap_sg(dev, data->buf, data->size, DMA_TO_DEVICE);
346 }
347 }
348
349 /**
350 * iser_reg_rdma_mem - Registers memory intended for RDMA,
351 * obtaining rkey and va
352 *
353 * returns 0 on success, errno code on failure
354 */
iser_reg_rdma_mem(struct iscsi_iser_task * iser_task,enum iser_data_dir cmd_dir)355 int iser_reg_rdma_mem(struct iscsi_iser_task *iser_task,
356 enum iser_data_dir cmd_dir)
357 {
358 struct iscsi_conn *iscsi_conn = iser_task->iser_conn->iscsi_conn;
359 struct iser_conn *ib_conn = iser_task->iser_conn->ib_conn;
360 struct iser_device *device = ib_conn->device;
361 struct ib_device *ibdev = device->ib_device;
362 struct iser_data_buf *mem = &iser_task->data[cmd_dir];
363 struct iser_regd_buf *regd_buf;
364 int aligned_len;
365 int err;
366 int i;
367 struct scatterlist *sg;
368
369 regd_buf = &iser_task->rdma_regd[cmd_dir];
370
371 aligned_len = iser_data_buf_aligned_len(mem, ibdev);
372 if (aligned_len != mem->dma_nents) {
373 iscsi_conn->fmr_unalign_cnt++;
374 iser_warn("rdma alignment violation %d/%d aligned\n",
375 aligned_len, mem->size);
376 iser_data_buf_dump(mem, ibdev);
377
378 /* unmap the command data before accessing it */
379 iser_dma_unmap_task_data(iser_task);
380
381 /* allocate copy buf, if we are writing, copy the */
382 /* unaligned scatterlist, dma map the copy */
383 if (iser_start_rdma_unaligned_sg(iser_task, cmd_dir) != 0)
384 return -ENOMEM;
385 mem = &iser_task->data_copy[cmd_dir];
386 }
387
388 /* if there a single dma entry, FMR is not needed */
389 if (mem->dma_nents == 1) {
390 sg = (struct scatterlist *)mem->buf;
391
392 regd_buf->reg.lkey = device->mr->lkey;
393 regd_buf->reg.rkey = device->mr->rkey;
394 regd_buf->reg.len = ib_sg_dma_len(ibdev, &sg[0]);
395 regd_buf->reg.va = ib_sg_dma_address(ibdev, &sg[0]);
396 regd_buf->reg.is_fmr = 0;
397
398 iser_dbg("PHYSICAL Mem.register: lkey: 0x%08X rkey: 0x%08X "
399 "va: 0x%08lX sz: %ld]\n",
400 (unsigned int)regd_buf->reg.lkey,
401 (unsigned int)regd_buf->reg.rkey,
402 (unsigned long)regd_buf->reg.va,
403 (unsigned long)regd_buf->reg.len);
404 } else { /* use FMR for multiple dma entries */
405 iser_page_vec_build(mem, ib_conn->page_vec, ibdev);
406 err = iser_reg_page_vec(ib_conn, ib_conn->page_vec, ®d_buf->reg);
407 if (err) {
408 iser_data_buf_dump(mem, ibdev);
409 iser_err("mem->dma_nents = %d (dlength = 0x%x)\n",
410 mem->dma_nents,
411 ntoh24(iser_task->desc.iscsi_header.dlength));
412 iser_err("page_vec: data_size = 0x%x, length = %d, offset = 0x%x\n",
413 ib_conn->page_vec->data_size, ib_conn->page_vec->length,
414 ib_conn->page_vec->offset);
415 for (i=0 ; i<ib_conn->page_vec->length ; i++)
416 iser_err("page_vec[%d] = 0x%llx\n", i,
417 (unsigned long long) ib_conn->page_vec->pages[i]);
418 return err;
419 }
420 }
421 return 0;
422 }
423