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authorOr Gerlitz <ogerlitz@voltaire.com>2006-05-11 03:03:08 -0400
committerRoland Dreier <rolandd@cisco.com>2006-06-22 10:51:12 -0400
commit6461f64ab51e6929680df064b2682004a1548290 (patch)
tree52922f1830a6f6ed7fe546db9230a507f91974a7
parent1cfa0a75dbef1d5bf687aacafabb023288f6b36a (diff)
IB/iser: iSER handling of memory for RDMA
This file contains the processing carried over an SG list associated with a SCSI command such that it can be registered with the IB verbs. The registration produces a network virtual address (VA) and a remote access key (RKEY or STAG in iSER spec notation) which are used by the target for its RDMA operation. Signed-off-by: Or Gerlitz <ogerlitz@voltaire.com> Signed-off-by: Roland Dreier <rolandd@cisco.com>
-rw-r--r--drivers/infiniband/ulp/iser/iser_memory.c401
1 files changed, 401 insertions, 0 deletions
diff --git a/drivers/infiniband/ulp/iser/iser_memory.c b/drivers/infiniband/ulp/iser/iser_memory.c
new file mode 100644
index 000000000000..31950a522a1c
--- /dev/null
+++ b/drivers/infiniband/ulp/iser/iser_memory.c
@@ -0,0 +1,401 @@
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 * $Id: iser_memory.c 6964 2006-05-07 11:11:43Z ogerlitz $
33 */
34#include <linux/module.h>
35#include <linux/kernel.h>
36#include <linux/slab.h>
37#include <linux/mm.h>
38#include <asm/io.h>
39#include <asm/scatterlist.h>
40#include <linux/scatterlist.h>
41
42#include "iscsi_iser.h"
43
44#define ISER_KMALLOC_THRESHOLD 0x20000 /* 128K - kmalloc limit */
45/**
46 * Decrements the reference count for the
47 * registered buffer & releases it
48 *
49 * returns 0 if released, 1 if deferred
50 */
51int iser_regd_buff_release(struct iser_regd_buf *regd_buf)
52{
53 struct device *dma_device;
54
55 if ((atomic_read(&regd_buf->ref_count) == 0) ||
56 atomic_dec_and_test(&regd_buf->ref_count)) {
57 /* if we used the dma mr, unreg is just NOP */
58 if (regd_buf->reg.rkey != 0)
59 iser_unreg_mem(&regd_buf->reg);
60
61 if (regd_buf->dma_addr) {
62 dma_device = regd_buf->device->ib_device->dma_device;
63 dma_unmap_single(dma_device,
64 regd_buf->dma_addr,
65 regd_buf->data_size,
66 regd_buf->direction);
67 }
68 /* else this regd buf is associated with task which we */
69 /* dma_unmap_single/sg later */
70 return 0;
71 } else {
72 iser_dbg("Release deferred, regd.buff: 0x%p\n", regd_buf);
73 return 1;
74 }
75}
76
77/**
78 * iser_reg_single - fills registered buffer descriptor with
79 * registration information
80 */
81void iser_reg_single(struct iser_device *device,
82 struct iser_regd_buf *regd_buf,
83 enum dma_data_direction direction)
84{
85 dma_addr_t dma_addr;
86
87 dma_addr = dma_map_single(device->ib_device->dma_device,
88 regd_buf->virt_addr,
89 regd_buf->data_size, direction);
90 BUG_ON(dma_mapping_error(dma_addr));
91
92 regd_buf->reg.lkey = device->mr->lkey;
93 regd_buf->reg.rkey = 0; /* indicate there's no need to unreg */
94 regd_buf->reg.len = regd_buf->data_size;
95 regd_buf->reg.va = dma_addr;
96
97 regd_buf->dma_addr = dma_addr;
98 regd_buf->direction = direction;
99}
100
101/**
102 * iser_start_rdma_unaligned_sg
103 */
104int iser_start_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
105 enum iser_data_dir cmd_dir)
106{
107 int dma_nents;
108 struct device *dma_device;
109 char *mem = NULL;
110 struct iser_data_buf *data = &iser_ctask->data[cmd_dir];
111 unsigned long cmd_data_len = data->data_len;
112
113 if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
114 mem = (void *)__get_free_pages(GFP_NOIO,
115 long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
116 else
117 mem = kmalloc(cmd_data_len, GFP_NOIO);
118
119 if (mem == NULL) {
120 iser_err("Failed to allocate mem size %d %d for copying sglist\n",
121 data->size,(int)cmd_data_len);
122 return -ENOMEM;
123 }
124
125 if (cmd_dir == ISER_DIR_OUT) {
126 /* copy the unaligned sg the buffer which is used for RDMA */
127 struct scatterlist *sg = (struct scatterlist *)data->buf;
128 int i;
129 char *p, *from;
130
131 for (p = mem, i = 0; i < data->size; i++) {
132 from = kmap_atomic(sg[i].page, KM_USER0);
133 memcpy(p,
134 from + sg[i].offset,
135 sg[i].length);
136 kunmap_atomic(from, KM_USER0);
137 p += sg[i].length;
138 }
139 }
140
141 sg_init_one(&iser_ctask->data_copy[cmd_dir].sg_single, mem, cmd_data_len);
142 iser_ctask->data_copy[cmd_dir].buf =
143 &iser_ctask->data_copy[cmd_dir].sg_single;
144 iser_ctask->data_copy[cmd_dir].size = 1;
145
146 iser_ctask->data_copy[cmd_dir].copy_buf = mem;
147
148 dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
149
150 if (cmd_dir == ISER_DIR_OUT)
151 dma_nents = dma_map_sg(dma_device,
152 &iser_ctask->data_copy[cmd_dir].sg_single,
153 1, DMA_TO_DEVICE);
154 else
155 dma_nents = dma_map_sg(dma_device,
156 &iser_ctask->data_copy[cmd_dir].sg_single,
157 1, DMA_FROM_DEVICE);
158
159 BUG_ON(dma_nents == 0);
160
161 iser_ctask->data_copy[cmd_dir].dma_nents = dma_nents;
162 return 0;
163}
164
165/**
166 * iser_finalize_rdma_unaligned_sg
167 */
168void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_cmd_task *iser_ctask,
169 enum iser_data_dir cmd_dir)
170{
171 struct device *dma_device;
172 struct iser_data_buf *mem_copy;
173 unsigned long cmd_data_len;
174
175 dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
176 mem_copy = &iser_ctask->data_copy[cmd_dir];
177
178 if (cmd_dir == ISER_DIR_OUT)
179 dma_unmap_sg(dma_device, &mem_copy->sg_single, 1,
180 DMA_TO_DEVICE);
181 else
182 dma_unmap_sg(dma_device, &mem_copy->sg_single, 1,
183 DMA_FROM_DEVICE);
184
185 if (cmd_dir == ISER_DIR_IN) {
186 char *mem;
187 struct scatterlist *sg;
188 unsigned char *p, *to;
189 unsigned int sg_size;
190 int i;
191
192 /* copy back read RDMA to unaligned sg */
193 mem = mem_copy->copy_buf;
194
195 sg = (struct scatterlist *)iser_ctask->data[ISER_DIR_IN].buf;
196 sg_size = iser_ctask->data[ISER_DIR_IN].size;
197
198 for (p = mem, i = 0; i < sg_size; i++){
199 to = kmap_atomic(sg[i].page, KM_SOFTIRQ0);
200 memcpy(to + sg[i].offset,
201 p,
202 sg[i].length);
203 kunmap_atomic(to, KM_SOFTIRQ0);
204 p += sg[i].length;
205 }
206 }
207
208 cmd_data_len = iser_ctask->data[cmd_dir].data_len;
209
210 if (cmd_data_len > ISER_KMALLOC_THRESHOLD)
211 free_pages((unsigned long)mem_copy->copy_buf,
212 long_log2(roundup_pow_of_two(cmd_data_len)) - PAGE_SHIFT);
213 else
214 kfree(mem_copy->copy_buf);
215
216 mem_copy->copy_buf = NULL;
217}
218
219/**
220 * iser_sg_to_page_vec - Translates scatterlist entries to physical addresses
221 * and returns the length of resulting physical address array (may be less than
222 * the original due to possible compaction).
223 *
224 * we build a "page vec" under the assumption that the SG meets the RDMA
225 * alignment requirements. Other then the first and last SG elements, all
226 * the "internal" elements can be compacted into a list whose elements are
227 * dma addresses of physical pages. The code supports also the weird case
228 * where --few fragments of the same page-- are present in the SG as
229 * consecutive elements. Also, it handles one entry SG.
230 */
231static int iser_sg_to_page_vec(struct iser_data_buf *data,
232 struct iser_page_vec *page_vec)
233{
234 struct scatterlist *sg = (struct scatterlist *)data->buf;
235 dma_addr_t first_addr, last_addr, page;
236 int start_aligned, end_aligned;
237 unsigned int cur_page = 0;
238 unsigned long total_sz = 0;
239 int i;
240
241 /* compute the offset of first element */
242 page_vec->offset = (u64) sg[0].offset;
243
244 for (i = 0; i < data->dma_nents; i++) {
245 total_sz += sg_dma_len(&sg[i]);
246
247 first_addr = sg_dma_address(&sg[i]);
248 last_addr = first_addr + sg_dma_len(&sg[i]);
249
250 start_aligned = !(first_addr & ~PAGE_MASK);
251 end_aligned = !(last_addr & ~PAGE_MASK);
252
253 /* continue to collect page fragments till aligned or SG ends */
254 while (!end_aligned && (i + 1 < data->dma_nents)) {
255 i++;
256 total_sz += sg_dma_len(&sg[i]);
257 last_addr = sg_dma_address(&sg[i]) + sg_dma_len(&sg[i]);
258 end_aligned = !(last_addr & ~PAGE_MASK);
259 }
260
261 first_addr = first_addr & PAGE_MASK;
262
263 for (page = first_addr; page < last_addr; page += PAGE_SIZE)
264 page_vec->pages[cur_page++] = page;
265
266 }
267 page_vec->data_size = total_sz;
268 iser_dbg("page_vec->data_size:%d cur_page %d\n", page_vec->data_size,cur_page);
269 return cur_page;
270}
271
272#define MASK_4K ((1UL << 12) - 1) /* 0xFFF */
273#define IS_4K_ALIGNED(addr) ((((unsigned long)addr) & MASK_4K) == 0)
274
275/**
276 * iser_data_buf_aligned_len - Tries to determine the maximal correctly aligned
277 * for RDMA sub-list of a scatter-gather list of memory buffers, and returns
278 * the number of entries which are aligned correctly. Supports the case where
279 * consecutive SG elements are actually fragments of the same physcial page.
280 */
281static unsigned int iser_data_buf_aligned_len(struct iser_data_buf *data)
282{
283 struct scatterlist *sg;
284 dma_addr_t end_addr, next_addr;
285 int i, cnt;
286 unsigned int ret_len = 0;
287
288 sg = (struct scatterlist *)data->buf;
289
290 for (cnt = 0, i = 0; i < data->dma_nents; i++, cnt++) {
291 /* iser_dbg("Checking sg iobuf [%d]: phys=0x%08lX "
292 "offset: %ld sz: %ld\n", i,
293 (unsigned long)page_to_phys(sg[i].page),
294 (unsigned long)sg[i].offset,
295 (unsigned long)sg[i].length); */
296 end_addr = sg_dma_address(&sg[i]) +
297 sg_dma_len(&sg[i]);
298 /* iser_dbg("Checking sg iobuf end address "
299 "0x%08lX\n", end_addr); */
300 if (i + 1 < data->dma_nents) {
301 next_addr = sg_dma_address(&sg[i+1]);
302 /* are i, i+1 fragments of the same page? */
303 if (end_addr == next_addr)
304 continue;
305 else if (!IS_4K_ALIGNED(end_addr)) {
306 ret_len = cnt + 1;
307 break;
308 }
309 }
310 }
311 if (i == data->dma_nents)
312 ret_len = cnt; /* loop ended */
313 iser_dbg("Found %d aligned entries out of %d in sg:0x%p\n",
314 ret_len, data->dma_nents, data);
315 return ret_len;
316}
317
318static void iser_data_buf_dump(struct iser_data_buf *data)
319{
320 struct scatterlist *sg = (struct scatterlist *)data->buf;
321 int i;
322
323 for (i = 0; i < data->size; i++)
324 iser_err("sg[%d] dma_addr:0x%lX page:0x%p "
325 "off:%d sz:%d dma_len:%d\n",
326 i, (unsigned long)sg_dma_address(&sg[i]),
327 sg[i].page, sg[i].offset,
328 sg[i].length,sg_dma_len(&sg[i]));
329}
330
331static void iser_dump_page_vec(struct iser_page_vec *page_vec)
332{
333 int i;
334
335 iser_err("page vec length %d data size %d\n",
336 page_vec->length, page_vec->data_size);
337 for (i = 0; i < page_vec->length; i++)
338 iser_err("%d %lx\n",i,(unsigned long)page_vec->pages[i]);
339}
340
341static void iser_page_vec_build(struct iser_data_buf *data,
342 struct iser_page_vec *page_vec)
343{
344 int page_vec_len = 0;
345
346 page_vec->length = 0;
347 page_vec->offset = 0;
348
349 iser_dbg("Translating sg sz: %d\n", data->dma_nents);
350 page_vec_len = iser_sg_to_page_vec(data,page_vec);
351 iser_dbg("sg len %d page_vec_len %d\n", data->dma_nents,page_vec_len);
352
353 page_vec->length = page_vec_len;
354
355 if (page_vec_len * PAGE_SIZE < page_vec->data_size) {
356 iser_err("page_vec too short to hold this SG\n");
357 iser_data_buf_dump(data);
358 iser_dump_page_vec(page_vec);
359 BUG();
360 }
361}
362
363/**
364 * iser_reg_rdma_mem - Registers memory intended for RDMA,
365 * obtaining rkey and va
366 *
367 * returns 0 on success, errno code on failure
368 */
369int iser_reg_rdma_mem(struct iscsi_iser_cmd_task *iser_ctask,
370 enum iser_data_dir cmd_dir)
371{
372 struct iser_conn *ib_conn = iser_ctask->iser_conn->ib_conn;
373 struct iser_data_buf *mem = &iser_ctask->data[cmd_dir];
374 struct iser_regd_buf *regd_buf;
375 int aligned_len;
376 int err;
377
378 regd_buf = &iser_ctask->rdma_regd[cmd_dir];
379
380 aligned_len = iser_data_buf_aligned_len(mem);
381 if (aligned_len != mem->size) {
382 iser_err("rdma alignment violation %d/%d aligned\n",
383 aligned_len, mem->size);
384 iser_data_buf_dump(mem);
385 /* allocate copy buf, if we are writing, copy the */
386 /* unaligned scatterlist, dma map the copy */
387 if (iser_start_rdma_unaligned_sg(iser_ctask, cmd_dir) != 0)
388 return -ENOMEM;
389 mem = &iser_ctask->data_copy[cmd_dir];
390 }
391
392 iser_page_vec_build(mem, ib_conn->page_vec);
393 err = iser_reg_page_vec(ib_conn, ib_conn->page_vec, &regd_buf->reg);
394 if (err)
395 return err;
396
397 /* take a reference on this regd buf such that it will not be released *
398 * (eg in send dto completion) before we get the scsi response */
399 atomic_inc(&regd_buf->ref_count);
400 return 0;
401}