1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*******************************************************************************
3 * SCSI RDMA Protocol lib functions
4 *
5 * Copyright (C) 2006 FUJITA Tomonori <tomof@acm.org>
6 * Copyright (C) 2016 Bryant G. Ly <bryantly@linux.vnet.ibm.com> IBM Corp.
7 *
8 ***********************************************************************/
9
10 #define pr_fmt(fmt) "libsrp: " fmt
11
12 #include <linux/printk.h>
13 #include <linux/err.h>
14 #include <linux/slab.h>
15 #include <linux/kfifo.h>
16 #include <linux/scatterlist.h>
17 #include <linux/dma-mapping.h>
18 #include <linux/module.h>
19 #include <scsi/srp.h>
20 #include <target/target_core_base.h>
21 #include "libsrp.h"
22 #include "ibmvscsi_tgt.h"
23
srp_iu_pool_alloc(struct srp_queue * q,size_t max,struct srp_buf ** ring)24 static int srp_iu_pool_alloc(struct srp_queue *q, size_t max,
25 struct srp_buf **ring)
26 {
27 struct iu_entry *iue;
28 int i;
29
30 q->pool = kcalloc(max, sizeof(struct iu_entry *), GFP_KERNEL);
31 if (!q->pool)
32 return -ENOMEM;
33 q->items = kcalloc(max, sizeof(struct iu_entry), GFP_KERNEL);
34 if (!q->items)
35 goto free_pool;
36
37 spin_lock_init(&q->lock);
38 kfifo_init(&q->queue, (void *)q->pool, max * sizeof(void *));
39
40 for (i = 0, iue = q->items; i < max; i++) {
41 kfifo_in(&q->queue, (void *)&iue, sizeof(void *));
42 iue->sbuf = ring[i];
43 iue++;
44 }
45 return 0;
46
47 free_pool:
48 kfree(q->pool);
49 return -ENOMEM;
50 }
51
srp_iu_pool_free(struct srp_queue * q)52 static void srp_iu_pool_free(struct srp_queue *q)
53 {
54 kfree(q->items);
55 kfree(q->pool);
56 }
57
srp_ring_alloc(struct device * dev,size_t max,size_t size)58 static struct srp_buf **srp_ring_alloc(struct device *dev,
59 size_t max, size_t size)
60 {
61 struct srp_buf **ring;
62 int i;
63
64 ring = kcalloc(max, sizeof(struct srp_buf *), GFP_KERNEL);
65 if (!ring)
66 return NULL;
67
68 for (i = 0; i < max; i++) {
69 ring[i] = kzalloc(sizeof(*ring[i]), GFP_KERNEL);
70 if (!ring[i])
71 goto out;
72 ring[i]->buf = dma_alloc_coherent(dev, size, &ring[i]->dma,
73 GFP_KERNEL);
74 if (!ring[i]->buf)
75 goto out;
76 }
77 return ring;
78
79 out:
80 for (i = 0; i < max && ring[i]; i++) {
81 if (ring[i]->buf) {
82 dma_free_coherent(dev, size, ring[i]->buf,
83 ring[i]->dma);
84 }
85 kfree(ring[i]);
86 }
87 kfree(ring);
88
89 return NULL;
90 }
91
srp_ring_free(struct device * dev,struct srp_buf ** ring,size_t max,size_t size)92 static void srp_ring_free(struct device *dev, struct srp_buf **ring,
93 size_t max, size_t size)
94 {
95 int i;
96
97 for (i = 0; i < max; i++) {
98 dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
99 kfree(ring[i]);
100 }
101 kfree(ring);
102 }
103
srp_target_alloc(struct srp_target * target,struct device * dev,size_t nr,size_t iu_size)104 int srp_target_alloc(struct srp_target *target, struct device *dev,
105 size_t nr, size_t iu_size)
106 {
107 int err;
108
109 spin_lock_init(&target->lock);
110
111 target->dev = dev;
112
113 target->srp_iu_size = iu_size;
114 target->rx_ring_size = nr;
115 target->rx_ring = srp_ring_alloc(target->dev, nr, iu_size);
116 if (!target->rx_ring)
117 return -ENOMEM;
118 err = srp_iu_pool_alloc(&target->iu_queue, nr, target->rx_ring);
119 if (err)
120 goto free_ring;
121
122 dev_set_drvdata(target->dev, target);
123 return 0;
124
125 free_ring:
126 srp_ring_free(target->dev, target->rx_ring, nr, iu_size);
127 return -ENOMEM;
128 }
129
srp_target_free(struct srp_target * target)130 void srp_target_free(struct srp_target *target)
131 {
132 dev_set_drvdata(target->dev, NULL);
133 srp_ring_free(target->dev, target->rx_ring, target->rx_ring_size,
134 target->srp_iu_size);
135 srp_iu_pool_free(&target->iu_queue);
136 }
137
srp_iu_get(struct srp_target * target)138 struct iu_entry *srp_iu_get(struct srp_target *target)
139 {
140 struct iu_entry *iue = NULL;
141
142 if (kfifo_out_locked(&target->iu_queue.queue, (void *)&iue,
143 sizeof(void *),
144 &target->iu_queue.lock) != sizeof(void *)) {
145 WARN_ONCE(1, "unexpected fifo state");
146 return NULL;
147 }
148 if (!iue)
149 return iue;
150 iue->target = target;
151 iue->flags = 0;
152 return iue;
153 }
154
srp_iu_put(struct iu_entry * iue)155 void srp_iu_put(struct iu_entry *iue)
156 {
157 kfifo_in_locked(&iue->target->iu_queue.queue, (void *)&iue,
158 sizeof(void *), &iue->target->iu_queue.lock);
159 }
160
srp_direct_data(struct ibmvscsis_cmd * cmd,struct srp_direct_buf * md,enum dma_data_direction dir,srp_rdma_t rdma_io,int dma_map,int ext_desc)161 static int srp_direct_data(struct ibmvscsis_cmd *cmd, struct srp_direct_buf *md,
162 enum dma_data_direction dir, srp_rdma_t rdma_io,
163 int dma_map, int ext_desc)
164 {
165 struct iu_entry *iue = NULL;
166 struct scatterlist *sg = NULL;
167 int err, nsg = 0, len;
168
169 if (dma_map) {
170 iue = cmd->iue;
171 sg = cmd->se_cmd.t_data_sg;
172 nsg = dma_map_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
173 DMA_BIDIRECTIONAL);
174 if (!nsg) {
175 pr_err("fail to map %p %d\n", iue,
176 cmd->se_cmd.t_data_nents);
177 return 0;
178 }
179 len = min(cmd->se_cmd.data_length, be32_to_cpu(md->len));
180 } else {
181 len = be32_to_cpu(md->len);
182 }
183
184 err = rdma_io(cmd, sg, nsg, md, 1, dir, len);
185
186 if (dma_map)
187 dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
188
189 return err;
190 }
191
srp_indirect_data(struct ibmvscsis_cmd * cmd,struct srp_cmd * srp_cmd,struct srp_indirect_buf * id,enum dma_data_direction dir,srp_rdma_t rdma_io,int dma_map,int ext_desc)192 static int srp_indirect_data(struct ibmvscsis_cmd *cmd, struct srp_cmd *srp_cmd,
193 struct srp_indirect_buf *id,
194 enum dma_data_direction dir, srp_rdma_t rdma_io,
195 int dma_map, int ext_desc)
196 {
197 struct iu_entry *iue = NULL;
198 struct srp_direct_buf *md = NULL;
199 struct scatterlist dummy, *sg = NULL;
200 dma_addr_t token = 0;
201 int err = 0;
202 int nmd, nsg = 0, len;
203
204 if (dma_map || ext_desc) {
205 iue = cmd->iue;
206 sg = cmd->se_cmd.t_data_sg;
207 }
208
209 nmd = be32_to_cpu(id->table_desc.len) / sizeof(struct srp_direct_buf);
210
211 if ((dir == DMA_FROM_DEVICE && nmd == srp_cmd->data_in_desc_cnt) ||
212 (dir == DMA_TO_DEVICE && nmd == srp_cmd->data_out_desc_cnt)) {
213 md = &id->desc_list[0];
214 goto rdma;
215 }
216
217 if (ext_desc && dma_map) {
218 md = dma_alloc_coherent(iue->target->dev,
219 be32_to_cpu(id->table_desc.len),
220 &token, GFP_KERNEL);
221 if (!md) {
222 pr_err("Can't get dma memory %u\n",
223 be32_to_cpu(id->table_desc.len));
224 return -ENOMEM;
225 }
226
227 sg_init_one(&dummy, md, be32_to_cpu(id->table_desc.len));
228 sg_dma_address(&dummy) = token;
229 sg_dma_len(&dummy) = be32_to_cpu(id->table_desc.len);
230 err = rdma_io(cmd, &dummy, 1, &id->table_desc, 1, DMA_TO_DEVICE,
231 be32_to_cpu(id->table_desc.len));
232 if (err) {
233 pr_err("Error copying indirect table %d\n", err);
234 goto free_mem;
235 }
236 } else {
237 pr_err("This command uses external indirect buffer\n");
238 return -EINVAL;
239 }
240
241 rdma:
242 if (dma_map) {
243 nsg = dma_map_sg(iue->target->dev, sg, cmd->se_cmd.t_data_nents,
244 DMA_BIDIRECTIONAL);
245 if (!nsg) {
246 pr_err("fail to map %p %d\n", iue,
247 cmd->se_cmd.t_data_nents);
248 err = -EIO;
249 goto free_mem;
250 }
251 len = min(cmd->se_cmd.data_length, be32_to_cpu(id->len));
252 } else {
253 len = be32_to_cpu(id->len);
254 }
255
256 err = rdma_io(cmd, sg, nsg, md, nmd, dir, len);
257
258 if (dma_map)
259 dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
260
261 free_mem:
262 if (token && dma_map) {
263 dma_free_coherent(iue->target->dev,
264 be32_to_cpu(id->table_desc.len), md, token);
265 }
266 return err;
267 }
268
data_out_desc_size(struct srp_cmd * cmd)269 static int data_out_desc_size(struct srp_cmd *cmd)
270 {
271 int size = 0;
272 u8 fmt = cmd->buf_fmt >> 4;
273
274 switch (fmt) {
275 case SRP_NO_DATA_DESC:
276 break;
277 case SRP_DATA_DESC_DIRECT:
278 size = sizeof(struct srp_direct_buf);
279 break;
280 case SRP_DATA_DESC_INDIRECT:
281 size = sizeof(struct srp_indirect_buf) +
282 sizeof(struct srp_direct_buf) * cmd->data_out_desc_cnt;
283 break;
284 default:
285 pr_err("client error. Invalid data_out_format %x\n", fmt);
286 break;
287 }
288 return size;
289 }
290
291 /*
292 * TODO: this can be called multiple times for a single command if it
293 * has very long data.
294 */
srp_transfer_data(struct ibmvscsis_cmd * cmd,struct srp_cmd * srp_cmd,srp_rdma_t rdma_io,int dma_map,int ext_desc)295 int srp_transfer_data(struct ibmvscsis_cmd *cmd, struct srp_cmd *srp_cmd,
296 srp_rdma_t rdma_io, int dma_map, int ext_desc)
297 {
298 struct srp_direct_buf *md;
299 struct srp_indirect_buf *id;
300 enum dma_data_direction dir;
301 int offset, err = 0;
302 u8 format;
303
304 if (!cmd->se_cmd.t_data_nents)
305 return 0;
306
307 offset = srp_cmd->add_cdb_len & ~3;
308
309 dir = srp_cmd_direction(srp_cmd);
310 if (dir == DMA_FROM_DEVICE)
311 offset += data_out_desc_size(srp_cmd);
312
313 if (dir == DMA_TO_DEVICE)
314 format = srp_cmd->buf_fmt >> 4;
315 else
316 format = srp_cmd->buf_fmt & ((1U << 4) - 1);
317
318 switch (format) {
319 case SRP_NO_DATA_DESC:
320 break;
321 case SRP_DATA_DESC_DIRECT:
322 md = (struct srp_direct_buf *)(srp_cmd->add_data + offset);
323 err = srp_direct_data(cmd, md, dir, rdma_io, dma_map, ext_desc);
324 break;
325 case SRP_DATA_DESC_INDIRECT:
326 id = (struct srp_indirect_buf *)(srp_cmd->add_data + offset);
327 err = srp_indirect_data(cmd, srp_cmd, id, dir, rdma_io, dma_map,
328 ext_desc);
329 break;
330 default:
331 pr_err("Unknown format %d %x\n", dir, format);
332 err = -EINVAL;
333 }
334
335 return err;
336 }
337
srp_data_length(struct srp_cmd * cmd,enum dma_data_direction dir)338 u64 srp_data_length(struct srp_cmd *cmd, enum dma_data_direction dir)
339 {
340 struct srp_direct_buf *md;
341 struct srp_indirect_buf *id;
342 u64 len = 0;
343 uint offset = cmd->add_cdb_len & ~3;
344 u8 fmt;
345
346 if (dir == DMA_TO_DEVICE) {
347 fmt = cmd->buf_fmt >> 4;
348 } else {
349 fmt = cmd->buf_fmt & ((1U << 4) - 1);
350 offset += data_out_desc_size(cmd);
351 }
352
353 switch (fmt) {
354 case SRP_NO_DATA_DESC:
355 break;
356 case SRP_DATA_DESC_DIRECT:
357 md = (struct srp_direct_buf *)(cmd->add_data + offset);
358 len = be32_to_cpu(md->len);
359 break;
360 case SRP_DATA_DESC_INDIRECT:
361 id = (struct srp_indirect_buf *)(cmd->add_data + offset);
362 len = be32_to_cpu(id->len);
363 break;
364 default:
365 pr_err("invalid data format %x\n", fmt);
366 break;
367 }
368 return len;
369 }
370
srp_get_desc_table(struct srp_cmd * srp_cmd,enum dma_data_direction * dir,u64 * data_len)371 int srp_get_desc_table(struct srp_cmd *srp_cmd, enum dma_data_direction *dir,
372 u64 *data_len)
373 {
374 struct srp_indirect_buf *idb;
375 struct srp_direct_buf *db;
376 uint add_cdb_offset;
377 int rc;
378
379 /*
380 * The pointer computations below will only be compiled correctly
381 * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
382 * whether srp_cmd::add_data has been declared as a byte pointer.
383 */
384 BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0)
385 && !__same_type(srp_cmd->add_data[0], (u8)0));
386
387 BUG_ON(!dir);
388 BUG_ON(!data_len);
389
390 rc = 0;
391 *data_len = 0;
392
393 *dir = DMA_NONE;
394
395 if (srp_cmd->buf_fmt & 0xf)
396 *dir = DMA_FROM_DEVICE;
397 else if (srp_cmd->buf_fmt >> 4)
398 *dir = DMA_TO_DEVICE;
399
400 add_cdb_offset = srp_cmd->add_cdb_len & ~3;
401 if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
402 ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
403 db = (struct srp_direct_buf *)(srp_cmd->add_data
404 + add_cdb_offset);
405 *data_len = be32_to_cpu(db->len);
406 } else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
407 ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
408 idb = (struct srp_indirect_buf *)(srp_cmd->add_data
409 + add_cdb_offset);
410
411 *data_len = be32_to_cpu(idb->len);
412 }
413 return rc;
414 }
415
416 MODULE_DESCRIPTION("SCSI RDMA Protocol lib functions");
417 MODULE_AUTHOR("FUJITA Tomonori");
418 MODULE_LICENSE("GPL");
419