[SCSI] megaraid_sas: Fix FastPath I/O to work on degraded raid 1
[linux-2.6.git] / drivers / scsi / libsrp.c
1 /*
2  * SCSI RDMA Protocol lib functions
3  *
4  * Copyright (C) 2006 FUJITA Tomonori <tomof@acm.org>
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License as
8  * published by the Free Software Foundation; either version 2 of the
9  * License, or (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful, but
12  * WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19  * 02110-1301 USA
20  */
21 #include <linux/err.h>
22 #include <linux/slab.h>
23 #include <linux/kfifo.h>
24 #include <linux/scatterlist.h>
25 #include <linux/dma-mapping.h>
26 #include <scsi/scsi.h>
27 #include <scsi/scsi_cmnd.h>
28 #include <scsi/scsi_tcq.h>
29 #include <scsi/scsi_tgt.h>
30 #include <scsi/srp.h>
31 #include <scsi/libsrp.h>
32
33 enum srp_task_attributes {
34         SRP_SIMPLE_TASK = 0,
35         SRP_HEAD_TASK = 1,
36         SRP_ORDERED_TASK = 2,
37         SRP_ACA_TASK = 4
38 };
39
40 /* tmp - will replace with SCSI logging stuff */
41 #define eprintk(fmt, args...)                                   \
42 do {                                                            \
43         printk("%s(%d) " fmt, __func__, __LINE__, ##args);      \
44 } while (0)
45 /* #define dprintk eprintk */
46 #define dprintk(fmt, args...)
47
48 static int srp_iu_pool_alloc(struct srp_queue *q, size_t max,
49                              struct srp_buf **ring)
50 {
51         int i;
52         struct iu_entry *iue;
53
54         q->pool = kcalloc(max, sizeof(struct iu_entry *), GFP_KERNEL);
55         if (!q->pool)
56                 return -ENOMEM;
57         q->items = kcalloc(max, sizeof(struct iu_entry), GFP_KERNEL);
58         if (!q->items)
59                 goto free_pool;
60
61         spin_lock_init(&q->lock);
62         kfifo_init(&q->queue, (void *) q->pool, max * sizeof(void *));
63
64         for (i = 0, iue = q->items; i < max; i++) {
65                 kfifo_in(&q->queue, (void *) &iue, sizeof(void *));
66                 iue->sbuf = ring[i];
67                 iue++;
68         }
69         return 0;
70
71         kfree(q->items);
72 free_pool:
73         kfree(q->pool);
74         return -ENOMEM;
75 }
76
77 static void srp_iu_pool_free(struct srp_queue *q)
78 {
79         kfree(q->items);
80         kfree(q->pool);
81 }
82
83 static struct srp_buf **srp_ring_alloc(struct device *dev,
84                                        size_t max, size_t size)
85 {
86         int i;
87         struct srp_buf **ring;
88
89         ring = kcalloc(max, sizeof(struct srp_buf *), GFP_KERNEL);
90         if (!ring)
91                 return NULL;
92
93         for (i = 0; i < max; i++) {
94                 ring[i] = kzalloc(sizeof(struct srp_buf), GFP_KERNEL);
95                 if (!ring[i])
96                         goto out;
97                 ring[i]->buf = dma_alloc_coherent(dev, size, &ring[i]->dma,
98                                                   GFP_KERNEL);
99                 if (!ring[i]->buf)
100                         goto out;
101         }
102         return ring;
103
104 out:
105         for (i = 0; i < max && ring[i]; i++) {
106                 if (ring[i]->buf)
107                         dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
108                 kfree(ring[i]);
109         }
110         kfree(ring);
111
112         return NULL;
113 }
114
115 static void srp_ring_free(struct device *dev, struct srp_buf **ring, size_t max,
116                           size_t size)
117 {
118         int i;
119
120         for (i = 0; i < max; i++) {
121                 dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
122                 kfree(ring[i]);
123         }
124         kfree(ring);
125 }
126
127 int srp_target_alloc(struct srp_target *target, struct device *dev,
128                      size_t nr, size_t iu_size)
129 {
130         int err;
131
132         spin_lock_init(&target->lock);
133         INIT_LIST_HEAD(&target->cmd_queue);
134
135         target->dev = dev;
136         dev_set_drvdata(target->dev, target);
137
138         target->srp_iu_size = iu_size;
139         target->rx_ring_size = nr;
140         target->rx_ring = srp_ring_alloc(target->dev, nr, iu_size);
141         if (!target->rx_ring)
142                 return -ENOMEM;
143         err = srp_iu_pool_alloc(&target->iu_queue, nr, target->rx_ring);
144         if (err)
145                 goto free_ring;
146
147         return 0;
148
149 free_ring:
150         srp_ring_free(target->dev, target->rx_ring, nr, iu_size);
151         return -ENOMEM;
152 }
153 EXPORT_SYMBOL_GPL(srp_target_alloc);
154
155 void srp_target_free(struct srp_target *target)
156 {
157         srp_ring_free(target->dev, target->rx_ring, target->rx_ring_size,
158                       target->srp_iu_size);
159         srp_iu_pool_free(&target->iu_queue);
160 }
161 EXPORT_SYMBOL_GPL(srp_target_free);
162
163 struct iu_entry *srp_iu_get(struct srp_target *target)
164 {
165         struct iu_entry *iue = NULL;
166
167         if (kfifo_out_locked(&target->iu_queue.queue, (void *) &iue,
168                 sizeof(void *), &target->iu_queue.lock) != sizeof(void *)) {
169                         WARN_ONCE(1, "unexpected fifo state");
170                         return NULL;
171         }
172         if (!iue)
173                 return iue;
174         iue->target = target;
175         INIT_LIST_HEAD(&iue->ilist);
176         iue->flags = 0;
177         return iue;
178 }
179 EXPORT_SYMBOL_GPL(srp_iu_get);
180
181 void srp_iu_put(struct iu_entry *iue)
182 {
183         kfifo_in_locked(&iue->target->iu_queue.queue, (void *) &iue,
184                         sizeof(void *), &iue->target->iu_queue.lock);
185 }
186 EXPORT_SYMBOL_GPL(srp_iu_put);
187
188 static int srp_direct_data(struct scsi_cmnd *sc, struct srp_direct_buf *md,
189                            enum dma_data_direction dir, srp_rdma_t rdma_io,
190                            int dma_map, int ext_desc)
191 {
192         struct iu_entry *iue = NULL;
193         struct scatterlist *sg = NULL;
194         int err, nsg = 0, len;
195
196         if (dma_map) {
197                 iue = (struct iu_entry *) sc->SCp.ptr;
198                 sg = scsi_sglist(sc);
199
200                 dprintk("%p %u %u %d\n", iue, scsi_bufflen(sc),
201                         md->len, scsi_sg_count(sc));
202
203                 nsg = dma_map_sg(iue->target->dev, sg, scsi_sg_count(sc),
204                                  DMA_BIDIRECTIONAL);
205                 if (!nsg) {
206                         printk("fail to map %p %d\n", iue, scsi_sg_count(sc));
207                         return 0;
208                 }
209                 len = min(scsi_bufflen(sc), md->len);
210         } else
211                 len = md->len;
212
213         err = rdma_io(sc, sg, nsg, md, 1, dir, len);
214
215         if (dma_map)
216                 dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
217
218         return err;
219 }
220
221 static int srp_indirect_data(struct scsi_cmnd *sc, struct srp_cmd *cmd,
222                              struct srp_indirect_buf *id,
223                              enum dma_data_direction dir, srp_rdma_t rdma_io,
224                              int dma_map, int ext_desc)
225 {
226         struct iu_entry *iue = NULL;
227         struct srp_direct_buf *md = NULL;
228         struct scatterlist dummy, *sg = NULL;
229         dma_addr_t token = 0;
230         int err = 0;
231         int nmd, nsg = 0, len;
232
233         if (dma_map || ext_desc) {
234                 iue = (struct iu_entry *) sc->SCp.ptr;
235                 sg = scsi_sglist(sc);
236
237                 dprintk("%p %u %u %d %d\n",
238                         iue, scsi_bufflen(sc), id->len,
239                         cmd->data_in_desc_cnt, cmd->data_out_desc_cnt);
240         }
241
242         nmd = id->table_desc.len / sizeof(struct srp_direct_buf);
243
244         if ((dir == DMA_FROM_DEVICE && nmd == cmd->data_in_desc_cnt) ||
245             (dir == DMA_TO_DEVICE && nmd == cmd->data_out_desc_cnt)) {
246                 md = &id->desc_list[0];
247                 goto rdma;
248         }
249
250         if (ext_desc && dma_map) {
251                 md = dma_alloc_coherent(iue->target->dev, id->table_desc.len,
252                                 &token, GFP_KERNEL);
253                 if (!md) {
254                         eprintk("Can't get dma memory %u\n", id->table_desc.len);
255                         return -ENOMEM;
256                 }
257
258                 sg_init_one(&dummy, md, id->table_desc.len);
259                 sg_dma_address(&dummy) = token;
260                 sg_dma_len(&dummy) = id->table_desc.len;
261                 err = rdma_io(sc, &dummy, 1, &id->table_desc, 1, DMA_TO_DEVICE,
262                               id->table_desc.len);
263                 if (err) {
264                         eprintk("Error copying indirect table %d\n", err);
265                         goto free_mem;
266                 }
267         } else {
268                 eprintk("This command uses external indirect buffer\n");
269                 return -EINVAL;
270         }
271
272 rdma:
273         if (dma_map) {
274                 nsg = dma_map_sg(iue->target->dev, sg, scsi_sg_count(sc),
275                                  DMA_BIDIRECTIONAL);
276                 if (!nsg) {
277                         eprintk("fail to map %p %d\n", iue, scsi_sg_count(sc));
278                         err = -EIO;
279                         goto free_mem;
280                 }
281                 len = min(scsi_bufflen(sc), id->len);
282         } else
283                 len = id->len;
284
285         err = rdma_io(sc, sg, nsg, md, nmd, dir, len);
286
287         if (dma_map)
288                 dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
289
290 free_mem:
291         if (token && dma_map)
292                 dma_free_coherent(iue->target->dev, id->table_desc.len, md, token);
293
294         return err;
295 }
296
297 static int data_out_desc_size(struct srp_cmd *cmd)
298 {
299         int size = 0;
300         u8 fmt = cmd->buf_fmt >> 4;
301
302         switch (fmt) {
303         case SRP_NO_DATA_DESC:
304                 break;
305         case SRP_DATA_DESC_DIRECT:
306                 size = sizeof(struct srp_direct_buf);
307                 break;
308         case SRP_DATA_DESC_INDIRECT:
309                 size = sizeof(struct srp_indirect_buf) +
310                         sizeof(struct srp_direct_buf) * cmd->data_out_desc_cnt;
311                 break;
312         default:
313                 eprintk("client error. Invalid data_out_format %x\n", fmt);
314                 break;
315         }
316         return size;
317 }
318
319 /*
320  * TODO: this can be called multiple times for a single command if it
321  * has very long data.
322  */
323 int srp_transfer_data(struct scsi_cmnd *sc, struct srp_cmd *cmd,
324                       srp_rdma_t rdma_io, int dma_map, int ext_desc)
325 {
326         struct srp_direct_buf *md;
327         struct srp_indirect_buf *id;
328         enum dma_data_direction dir;
329         int offset, err = 0;
330         u8 format;
331
332         offset = cmd->add_cdb_len & ~3;
333
334         dir = srp_cmd_direction(cmd);
335         if (dir == DMA_FROM_DEVICE)
336                 offset += data_out_desc_size(cmd);
337
338         if (dir == DMA_TO_DEVICE)
339                 format = cmd->buf_fmt >> 4;
340         else
341                 format = cmd->buf_fmt & ((1U << 4) - 1);
342
343         switch (format) {
344         case SRP_NO_DATA_DESC:
345                 break;
346         case SRP_DATA_DESC_DIRECT:
347                 md = (struct srp_direct_buf *)
348                         (cmd->add_data + offset);
349                 err = srp_direct_data(sc, md, dir, rdma_io, dma_map, ext_desc);
350                 break;
351         case SRP_DATA_DESC_INDIRECT:
352                 id = (struct srp_indirect_buf *)
353                         (cmd->add_data + offset);
354                 err = srp_indirect_data(sc, cmd, id, dir, rdma_io, dma_map,
355                                         ext_desc);
356                 break;
357         default:
358                 eprintk("Unknown format %d %x\n", dir, format);
359                 err = -EINVAL;
360         }
361
362         return err;
363 }
364 EXPORT_SYMBOL_GPL(srp_transfer_data);
365
366 static int vscsis_data_length(struct srp_cmd *cmd, enum dma_data_direction dir)
367 {
368         struct srp_direct_buf *md;
369         struct srp_indirect_buf *id;
370         int len = 0, offset = cmd->add_cdb_len & ~3;
371         u8 fmt;
372
373         if (dir == DMA_TO_DEVICE)
374                 fmt = cmd->buf_fmt >> 4;
375         else {
376                 fmt = cmd->buf_fmt & ((1U << 4) - 1);
377                 offset += data_out_desc_size(cmd);
378         }
379
380         switch (fmt) {
381         case SRP_NO_DATA_DESC:
382                 break;
383         case SRP_DATA_DESC_DIRECT:
384                 md = (struct srp_direct_buf *) (cmd->add_data + offset);
385                 len = md->len;
386                 break;
387         case SRP_DATA_DESC_INDIRECT:
388                 id = (struct srp_indirect_buf *) (cmd->add_data + offset);
389                 len = id->len;
390                 break;
391         default:
392                 eprintk("invalid data format %x\n", fmt);
393                 break;
394         }
395         return len;
396 }
397
398 int srp_cmd_queue(struct Scsi_Host *shost, struct srp_cmd *cmd, void *info,
399                   u64 itn_id, u64 addr)
400 {
401         enum dma_data_direction dir;
402         struct scsi_cmnd *sc;
403         int tag, len, err;
404
405         switch (cmd->task_attr) {
406         case SRP_SIMPLE_TASK:
407                 tag = MSG_SIMPLE_TAG;
408                 break;
409         case SRP_ORDERED_TASK:
410                 tag = MSG_ORDERED_TAG;
411                 break;
412         case SRP_HEAD_TASK:
413                 tag = MSG_HEAD_TAG;
414                 break;
415         default:
416                 eprintk("Task attribute %d not supported\n", cmd->task_attr);
417                 tag = MSG_ORDERED_TAG;
418         }
419
420         dir = srp_cmd_direction(cmd);
421         len = vscsis_data_length(cmd, dir);
422
423         dprintk("%p %x %lx %d %d %d %llx\n", info, cmd->cdb[0],
424                 cmd->lun, dir, len, tag, (unsigned long long) cmd->tag);
425
426         sc = scsi_host_get_command(shost, dir, GFP_KERNEL);
427         if (!sc)
428                 return -ENOMEM;
429
430         sc->SCp.ptr = info;
431         memcpy(sc->cmnd, cmd->cdb, MAX_COMMAND_SIZE);
432         sc->sdb.length = len;
433         sc->sdb.table.sgl = (void *) (unsigned long) addr;
434         sc->tag = tag;
435         err = scsi_tgt_queue_command(sc, itn_id, (struct scsi_lun *)&cmd->lun,
436                                      cmd->tag);
437         if (err)
438                 scsi_host_put_command(shost, sc);
439
440         return err;
441 }
442 EXPORT_SYMBOL_GPL(srp_cmd_queue);
443
444 MODULE_DESCRIPTION("SCSI RDMA Protocol lib functions");
445 MODULE_AUTHOR("FUJITA Tomonori");
446 MODULE_LICENSE("GPL");