treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
[sfrench/cifs-2.6.git] / drivers / scsi / ibmvscsi_tgt / libsrp.c
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
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
52 static void srp_iu_pool_free(struct srp_queue *q)
53 {
54         kfree(q->items);
55         kfree(q->pool);
56 }
57
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
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
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
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
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
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
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
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
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  */
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
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
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");