aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/scsi/scsi_tgt_if.c
blob: 0e08817fdecff73540e2c35bbddb1c4f266acb42 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
/*
 * SCSI target kernel/user interface functions
 *
 * Copyright (C) 2005 FUJITA Tomonori <tomof@acm.org>
 * Copyright (C) 2005 Mike Christie <michaelc@cs.wisc.edu>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */
#include <linux/miscdevice.h>
#include <linux/file.h>
#include <net/tcp.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tgt.h>
#include <scsi/scsi_tgt_if.h>

#include <asm/cacheflush.h>

#include "scsi_tgt_priv.h"

#if TGT_RING_SIZE < PAGE_SIZE
#  define TGT_RING_SIZE PAGE_SIZE
#endif

#define TGT_RING_PAGES (TGT_RING_SIZE >> PAGE_SHIFT)
#define TGT_EVENT_PER_PAGE (PAGE_SIZE / sizeof(struct tgt_event))
#define TGT_MAX_EVENTS (TGT_EVENT_PER_PAGE * TGT_RING_PAGES)

struct tgt_ring {
	u32 tr_idx;
	unsigned long tr_pages[TGT_RING_PAGES];
	spinlock_t tr_lock;
};

/* tx_ring : kernel->user, rx_ring : user->kernel */
static struct tgt_ring tx_ring, rx_ring;
static DECLARE_WAIT_QUEUE_HEAD(tgt_poll_wait);

static inline void tgt_ring_idx_inc(struct tgt_ring *ring)
{
	if (ring->tr_idx == TGT_MAX_EVENTS - 1)
		ring->tr_idx = 0;
	else
		ring->tr_idx++;
}

static struct tgt_event *tgt_head_event(struct tgt_ring *ring, u32 idx)
{
	u32 pidx, off;

	pidx = idx / TGT_EVENT_PER_PAGE;
	off = idx % TGT_EVENT_PER_PAGE;

	return (struct tgt_event *)
		(ring->tr_pages[pidx] + sizeof(struct tgt_event) * off);
}

static int tgt_uspace_send_event(u32 type, struct tgt_event *p)
{
	struct tgt_event *ev;
	struct tgt_ring *ring = &tx_ring;
	unsigned long flags;
	int err = 0;

	spin_lock_irqsave(&ring->tr_lock, flags);

	ev = tgt_head_event(ring, ring->tr_idx);
	if (!ev->hdr.status)
		tgt_ring_idx_inc(ring);
	else
		err = -BUSY;

	spin_unlock_irqrestore(&ring->tr_lock, flags);

	if (err)
		return err;

	memcpy(ev, p, sizeof(*ev));
	ev->hdr.type = type;
	mb();
	ev->hdr.status = 1;

	flush_dcache_page(virt_to_page(ev));

	wake_up_interruptible(&tgt_poll_wait);

	return 0;
}

int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, struct scsi_lun *lun, u64 tag)
{
	struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
	struct tgt_event ev;
	int err;

	memset(&ev, 0, sizeof(ev));
	ev.p.cmd_req.host_no = shost->host_no;
	ev.p.cmd_req.data_len = cmd->request_bufflen;
	memcpy(ev.p.cmd_req.scb, cmd->cmnd, sizeof(ev.p.cmd_req.scb));
	memcpy(ev.p.cmd_req.lun, lun, sizeof(ev.p.cmd_req.lun));
	ev.p.cmd_req.attribute = cmd->tag;
	ev.p.cmd_req.tag = tag;

	dprintk("%p %d %u %x %llx\n", cmd, shost->host_no,
		ev.p.cmd_req.data_len, cmd->tag,
		(unsigned long long) ev.p.cmd_req.tag);

	err = tgt_uspace_send_event(TGT_KEVENT_CMD_REQ, &ev);
	if (err)
		eprintk("tx buf is full, could not send\n");

	return err;
}

int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 tag)
{
	struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
	struct tgt_event ev;
	int err;

	memset(&ev, 0, sizeof(ev));
	ev.p.cmd_done.host_no = shost->host_no;
	ev.p.cmd_done.tag = tag;
	ev.p.cmd_done.result = cmd->result;

	dprintk("%p %d %llu %u %x\n", cmd, shost->host_no,
		(unsigned long long) ev.p.cmd_req.tag,
		ev.p.cmd_req.data_len, cmd->tag);

	err = tgt_uspace_send_event(TGT_KEVENT_CMD_DONE, &ev);
	if (err)
		eprintk("tx buf is full, could not send\n");

	return err;
}

int scsi_tgt_uspace_send_tsk_mgmt(int host_no, int function, u64 tag,
				  struct scsi_lun *scsilun, void *data)
{
	struct tgt_event ev;
	int err;

	memset(&ev, 0, sizeof(ev));
	ev.p.tsk_mgmt_req.host_no = host_no;
	ev.p.tsk_mgmt_req.function = function;
	ev.p.tsk_mgmt_req.tag = tag;
	memcpy(ev.p.tsk_mgmt_req.lun, scsilun, sizeof(ev.p.tsk_mgmt_req.lun));
	ev.p.tsk_mgmt_req.mid = (u64) (unsigned long) data;

	dprintk("%d %x %llx %llx\n", host_no, function, (unsigned long long) tag,
		(unsigned long long) ev.p.tsk_mgmt_req.mid);

	err = tgt_uspace_send_event(TGT_KEVENT_TSK_MGMT_REQ, &ev);
	if (err)
		eprintk("tx buf is full, could not send\n");

	return err;
}

static int event_recv_msg(struct tgt_event *ev)
{
	int err = 0;

	switch (ev->hdr.type) {
	case TGT_UEVENT_CMD_RSP:
		err = scsi_tgt_kspace_exec(ev->p.cmd_rsp.host_no,
					   ev->p.cmd_rsp.tag,
					   ev->p.cmd_rsp.result,
					   ev->p.cmd_rsp.len,
					   ev->p.cmd_rsp.uaddr,
					   ev->p.cmd_rsp.rw);
		break;
	case TGT_UEVENT_TSK_MGMT_RSP:
		err = scsi_tgt_kspace_tsk_mgmt(ev->p.tsk_mgmt_rsp.host_no,
					       ev->p.tsk_mgmt_rsp.mid,
					       ev->p.tsk_mgmt_rsp.result);
		break;
	default:
		eprintk("unknown type %d\n", ev->hdr.type);
		err = -EINVAL;
	}

	return err;
}

static ssize_t tgt_write(struct file *file, const char __user * buffer,
			 size_t count, loff_t * ppos)
{
	struct tgt_event *ev;
	struct tgt_ring *ring = &rx_ring;

	while (1) {
		ev = tgt_head_event(ring, ring->tr_idx);
		/* do we need this? */
		flush_dcache_page(virt_to_page(ev));

		if (!ev->hdr.status)
			break;

		tgt_ring_idx_inc(ring);
		event_recv_msg(ev);
		ev->hdr.status = 0;
	};

	return count;
}

static unsigned int tgt_poll(struct file * file, struct poll_table_struct *wait)
{
	struct tgt_event *ev;
	struct tgt_ring *ring = &tx_ring;
	unsigned long flags;
	unsigned int mask = 0;
	u32 idx;

	poll_wait(file, &tgt_poll_wait, wait);

	spin_lock_irqsave(&ring->tr_lock, flags);

	idx = ring->tr_idx ? ring->tr_idx - 1 : TGT_MAX_EVENTS - 1;
	ev = tgt_head_event(ring, idx);
	if (ev->hdr.status)
		mask |= POLLIN | POLLRDNORM;

	spin_unlock_irqrestore(&ring->tr_lock, flags);

	return mask;
}

static int uspace_ring_map(struct vm_area_struct *vma, unsigned long addr,
			   struct tgt_ring *ring)
{
	int i, err;

	for (i = 0; i < TGT_RING_PAGES; i++) {
		struct page *page = virt_to_page(ring->tr_pages[i]);
		err = vm_insert_page(vma, addr, page);
		if (err)
			return err;
		addr += PAGE_SIZE;
	}

	return 0;
}

static int tgt_mmap(struct file *filp, struct vm_area_struct *vma)
{
	unsigned long addr;
	int err;

	if (vma->vm_pgoff)
		return -EINVAL;

	if (vma->vm_end - vma->vm_start != TGT_RING_SIZE * 2) {
		eprintk("mmap size must be %lu, not %lu \n",
			TGT_RING_SIZE * 2, vma->vm_end - vma->vm_start);
		return -EINVAL;
	}

	addr = vma->vm_start;
	err = uspace_ring_map(vma, addr, &tx_ring);
	if (err)
		return err;
	err = uspace_ring_map(vma, addr + TGT_RING_SIZE, &rx_ring);

	return err;
}

static int tgt_open(struct inode *inode, struct file *file)
{
	tx_ring.tr_idx = rx_ring.tr_idx = 0;

	return 0;
}

static const struct file_operations tgt_fops = {
	.owner		= THIS_MODULE,
	.open		= tgt_open,
	.poll		= tgt_poll,
	.write		= tgt_write,
	.mmap		= tgt_mmap,
};

static struct miscdevice tgt_miscdev = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = "tgt",
	.fops = &tgt_fops,
};

static void tgt_ring_exit(struct tgt_ring *ring)
{
	int i;

	for (i = 0; i < TGT_RING_PAGES; i++)
		free_page(ring->tr_pages[i]);
}

static int tgt_ring_init(struct tgt_ring *ring)
{
	int i;

	spin_lock_init(&ring->tr_lock);

	for (i = 0; i < TGT_RING_PAGES; i++) {
		ring->tr_pages[i] = get_zeroed_page(GFP_KERNEL);
		if (!ring->tr_pages[i]) {
			eprintk("out of memory\n");
			return -ENOMEM;
		}
	}

	return 0;
}

void scsi_tgt_if_exit(void)
{
	tgt_ring_exit(&tx_ring);
	tgt_ring_exit(&rx_ring);
	misc_deregister(&tgt_miscdev);
}

int scsi_tgt_if_init(void)
{
	int err;

	err = tgt_ring_init(&tx_ring);
	if (err)
		return err;

	err = tgt_ring_init(&rx_ring);
	if (err)
		goto free_tx_ring;

	err = misc_register(&tgt_miscdev);
	if (err)
		goto free_rx_ring;

	return 0;
free_rx_ring:
	tgt_ring_exit(&rx_ring);
free_tx_ring:
	tgt_ring_exit(&tx_ring);

	return err;
}