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1/* Copyright (c) 2012 Coraid, Inc. See COPYING for GPL terms. */
2/*
3 * aoechr.c
4 * AoE character device driver
5 */
6
7#include <linux/hdreg.h>
8#include <linux/blkdev.h>
9#include <linux/completion.h>
10#include <linux/delay.h>
11#include <linux/slab.h>
12#include <linux/mutex.h>
13#include <linux/skbuff.h>
14#include <linux/export.h>
15#include "aoe.h"
16
17enum {
18 //MINOR_STAT = 1, (moved to sysfs)
19 MINOR_ERR = 2,
20 MINOR_DISCOVER,
21 MINOR_INTERFACES,
22 MINOR_REVALIDATE,
23 MINOR_FLUSH,
24 MSGSZ = 2048,
25 NMSG = 100, /* message backlog to retain */
26};
27
28struct aoe_chardev {
29 ulong minor;
30 char name[32];
31};
32
33enum { EMFL_VALID = 1 };
34
35struct ErrMsg {
36 short flags;
37 short len;
38 char *msg;
39};
40
41static DEFINE_MUTEX(aoechr_mutex);
42
43/* A ring buffer of error messages, to be read through
44 * "/dev/etherd/err". When no messages are present,
45 * readers will block waiting for messages to appear.
46 */
47static struct ErrMsg emsgs[NMSG];
48static int emsgs_head_idx, emsgs_tail_idx;
49static struct completion emsgs_comp;
50static spinlock_t emsgs_lock;
51static int nblocked_emsgs_readers;
52static struct class *aoe_class;
53static struct aoe_chardev chardevs[] = {
54 { MINOR_ERR, "err" },
55 { MINOR_DISCOVER, "discover" },
56 { MINOR_INTERFACES, "interfaces" },
57 { MINOR_REVALIDATE, "revalidate" },
58 { MINOR_FLUSH, "flush" },
59};
60
61static int
62discover(void)
63{
64 aoecmd_cfg(0xffff, 0xff);
65 return 0;
66}
67
68static int
69interfaces(const char __user *str, size_t size)
70{
71 if (set_aoe_iflist(str, size)) {
72 printk(KERN_ERR
73 "aoe: could not set interface list: too many interfaces\n");
74 return -EINVAL;
75 }
76 return 0;
77}
78
79static int
80revalidate(const char __user *str, size_t size)
81{
82 int major, minor, n;
83 ulong flags;
84 struct aoedev *d;
85 struct sk_buff *skb;
86 char buf[16];
87
88 if (size >= sizeof buf)
89 return -EINVAL;
90 buf[sizeof buf - 1] = '\0';
91 if (copy_from_user(buf, str, size))
92 return -EFAULT;
93
94 n = sscanf(buf, "e%d.%d", &major, &minor);
95 if (n != 2) {
96 pr_err("aoe: invalid device specification %s\n", buf);
97 return -EINVAL;
98 }
99 d = aoedev_by_aoeaddr(major, minor, 0);
100 if (!d)
101 return -EINVAL;
102 spin_lock_irqsave(&d->lock, flags);
103 aoecmd_cleanslate(d);
104 aoecmd_cfg(major, minor);
105loop:
106 skb = aoecmd_ata_id(d);
107 spin_unlock_irqrestore(&d->lock, flags);
108 /* try again if we are able to sleep a bit,
109 * otherwise give up this revalidation
110 */
111 if (!skb && !msleep_interruptible(250)) {
112 spin_lock_irqsave(&d->lock, flags);
113 goto loop;
114 }
115 aoedev_put(d);
116 if (skb) {
117 struct sk_buff_head queue;
118 __skb_queue_head_init(&queue);
119 __skb_queue_tail(&queue, skb);
120 aoenet_xmit(&queue);
121 }
122 return 0;
123}
124
125void
126aoechr_error(char *msg)
127{
128 struct ErrMsg *em;
129 char *mp;
130 ulong flags, n;
131
132 n = strlen(msg);
133
134 spin_lock_irqsave(&emsgs_lock, flags);
135
136 em = emsgs + emsgs_tail_idx;
137 if ((em->flags & EMFL_VALID)) {
138bail: spin_unlock_irqrestore(&emsgs_lock, flags);
139 return;
140 }
141
142 mp = kmemdup(msg, n, GFP_ATOMIC);
143 if (mp == NULL) {
144 printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n);
145 goto bail;
146 }
147
148 em->msg = mp;
149 em->flags |= EMFL_VALID;
150 em->len = n;
151
152 emsgs_tail_idx++;
153 emsgs_tail_idx %= ARRAY_SIZE(emsgs);
154
155 spin_unlock_irqrestore(&emsgs_lock, flags);
156
157 if (nblocked_emsgs_readers)
158 complete(&emsgs_comp);
159}
160
161static ssize_t
162aoechr_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offp)
163{
164 int ret = -EINVAL;
165
166 switch ((unsigned long) filp->private_data) {
167 default:
168 printk(KERN_INFO "aoe: can't write to that file.\n");
169 break;
170 case MINOR_DISCOVER:
171 ret = discover();
172 break;
173 case MINOR_INTERFACES:
174 ret = interfaces(buf, cnt);
175 break;
176 case MINOR_REVALIDATE:
177 ret = revalidate(buf, cnt);
178 break;
179 case MINOR_FLUSH:
180 ret = aoedev_flush(buf, cnt);
181 break;
182 }
183 if (ret == 0)
184 ret = cnt;
185 return ret;
186}
187
188static int
189aoechr_open(struct inode *inode, struct file *filp)
190{
191 int n, i;
192
193 mutex_lock(&aoechr_mutex);
194 n = iminor(inode);
195 filp->private_data = (void *) (unsigned long) n;
196
197 for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
198 if (chardevs[i].minor == n) {
199 mutex_unlock(&aoechr_mutex);
200 return 0;
201 }
202 mutex_unlock(&aoechr_mutex);
203 return -EINVAL;
204}
205
206static int
207aoechr_rel(struct inode *inode, struct file *filp)
208{
209 return 0;
210}
211
212static ssize_t
213aoechr_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off)
214{
215 unsigned long n;
216 char *mp;
217 struct ErrMsg *em;
218 ssize_t len;
219 ulong flags;
220
221 n = (unsigned long) filp->private_data;
222 if (n != MINOR_ERR)
223 return -EFAULT;
224
225 spin_lock_irqsave(&emsgs_lock, flags);
226
227 for (;;) {
228 em = emsgs + emsgs_head_idx;
229 if ((em->flags & EMFL_VALID) != 0)
230 break;
231 if (filp->f_flags & O_NDELAY) {
232 spin_unlock_irqrestore(&emsgs_lock, flags);
233 return -EAGAIN;
234 }
235 nblocked_emsgs_readers++;
236
237 spin_unlock_irqrestore(&emsgs_lock, flags);
238
239 n = wait_for_completion_interruptible(&emsgs_comp);
240
241 spin_lock_irqsave(&emsgs_lock, flags);
242
243 nblocked_emsgs_readers--;
244
245 if (n) {
246 spin_unlock_irqrestore(&emsgs_lock, flags);
247 return -ERESTARTSYS;
248 }
249 }
250 if (em->len > cnt) {
251 spin_unlock_irqrestore(&emsgs_lock, flags);
252 return -EAGAIN;
253 }
254 mp = em->msg;
255 len = em->len;
256 em->msg = NULL;
257 em->flags &= ~EMFL_VALID;
258
259 emsgs_head_idx++;
260 emsgs_head_idx %= ARRAY_SIZE(emsgs);
261
262 spin_unlock_irqrestore(&emsgs_lock, flags);
263
264 n = copy_to_user(buf, mp, len);
265 kfree(mp);
266 return n == 0 ? len : -EFAULT;
267}
268
269static const struct file_operations aoe_fops = {
270 .write = aoechr_write,
271 .read = aoechr_read,
272 .open = aoechr_open,
273 .release = aoechr_rel,
274 .owner = THIS_MODULE,
275 .llseek = noop_llseek,
276};
277
278static char *aoe_devnode(struct device *dev, umode_t *mode)
279{
280 return kasprintf(GFP_KERNEL, "etherd/%s", dev_name(dev));
281}
282
283int __init
284aoechr_init(void)
285{
286 int n, i;
287
288 n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops);
289 if (n < 0) {
290 printk(KERN_ERR "aoe: can't register char device\n");
291 return n;
292 }
293 init_completion(&emsgs_comp);
294 spin_lock_init(&emsgs_lock);
295 aoe_class = class_create(THIS_MODULE, "aoe");
296 if (IS_ERR(aoe_class)) {
297 unregister_chrdev(AOE_MAJOR, "aoechr");
298 return PTR_ERR(aoe_class);
299 }
300 aoe_class->devnode = aoe_devnode;
301
302 for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
303 device_create(aoe_class, NULL,
304 MKDEV(AOE_MAJOR, chardevs[i].minor), NULL,
305 chardevs[i].name);
306
307 return 0;
308}
309
310void
311aoechr_exit(void)
312{
313 int i;
314
315 for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
316 device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
317 class_destroy(aoe_class);
318 unregister_chrdev(AOE_MAJOR, "aoechr");
319}
320
1/* Copyright (c) 2012 Coraid, Inc. See COPYING for GPL terms. */
2/*
3 * aoechr.c
4 * AoE character device driver
5 */
6
7#include <linux/hdreg.h>
8#include <linux/blkdev.h>
9#include <linux/completion.h>
10#include <linux/delay.h>
11#include <linux/slab.h>
12#include <linux/mutex.h>
13#include <linux/skbuff.h>
14#include <linux/export.h>
15#include "aoe.h"
16
17enum {
18 //MINOR_STAT = 1, (moved to sysfs)
19 MINOR_ERR = 2,
20 MINOR_DISCOVER,
21 MINOR_INTERFACES,
22 MINOR_REVALIDATE,
23 MINOR_FLUSH,
24 MSGSZ = 2048,
25 NMSG = 100, /* message backlog to retain */
26};
27
28struct aoe_chardev {
29 ulong minor;
30 char name[32];
31};
32
33enum { EMFL_VALID = 1 };
34
35struct ErrMsg {
36 short flags;
37 short len;
38 char *msg;
39};
40
41static DEFINE_MUTEX(aoechr_mutex);
42
43/* A ring buffer of error messages, to be read through
44 * "/dev/etherd/err". When no messages are present,
45 * readers will block waiting for messages to appear.
46 */
47static struct ErrMsg emsgs[NMSG];
48static int emsgs_head_idx, emsgs_tail_idx;
49static struct completion emsgs_comp;
50static spinlock_t emsgs_lock;
51static int nblocked_emsgs_readers;
52
53static struct aoe_chardev chardevs[] = {
54 { MINOR_ERR, "err" },
55 { MINOR_DISCOVER, "discover" },
56 { MINOR_INTERFACES, "interfaces" },
57 { MINOR_REVALIDATE, "revalidate" },
58 { MINOR_FLUSH, "flush" },
59};
60
61static char *aoe_devnode(const struct device *dev, umode_t *mode)
62{
63 return kasprintf(GFP_KERNEL, "etherd/%s", dev_name(dev));
64}
65
66static const struct class aoe_class = {
67 .name = "aoe",
68 .devnode = aoe_devnode,
69};
70
71static int
72discover(void)
73{
74 aoecmd_cfg(0xffff, 0xff);
75 return 0;
76}
77
78static int
79interfaces(const char __user *str, size_t size)
80{
81 if (set_aoe_iflist(str, size)) {
82 printk(KERN_ERR
83 "aoe: could not set interface list: too many interfaces\n");
84 return -EINVAL;
85 }
86 return 0;
87}
88
89static int
90revalidate(const char __user *str, size_t size)
91{
92 int major, minor, n;
93 ulong flags;
94 struct aoedev *d;
95 struct sk_buff *skb;
96 char buf[16];
97
98 if (size >= sizeof buf)
99 return -EINVAL;
100 buf[sizeof buf - 1] = '\0';
101 if (copy_from_user(buf, str, size))
102 return -EFAULT;
103
104 n = sscanf(buf, "e%d.%d", &major, &minor);
105 if (n != 2) {
106 pr_err("aoe: invalid device specification %s\n", buf);
107 return -EINVAL;
108 }
109 d = aoedev_by_aoeaddr(major, minor, 0);
110 if (!d)
111 return -EINVAL;
112 spin_lock_irqsave(&d->lock, flags);
113 aoecmd_cleanslate(d);
114 aoecmd_cfg(major, minor);
115loop:
116 skb = aoecmd_ata_id(d);
117 spin_unlock_irqrestore(&d->lock, flags);
118 /* try again if we are able to sleep a bit,
119 * otherwise give up this revalidation
120 */
121 if (!skb && !msleep_interruptible(250)) {
122 spin_lock_irqsave(&d->lock, flags);
123 goto loop;
124 }
125 aoedev_put(d);
126 if (skb) {
127 struct sk_buff_head queue;
128 __skb_queue_head_init(&queue);
129 __skb_queue_tail(&queue, skb);
130 aoenet_xmit(&queue);
131 }
132 return 0;
133}
134
135void
136aoechr_error(char *msg)
137{
138 struct ErrMsg *em;
139 char *mp;
140 ulong flags, n;
141
142 n = strlen(msg);
143
144 spin_lock_irqsave(&emsgs_lock, flags);
145
146 em = emsgs + emsgs_tail_idx;
147 if ((em->flags & EMFL_VALID)) {
148bail: spin_unlock_irqrestore(&emsgs_lock, flags);
149 return;
150 }
151
152 mp = kmemdup(msg, n, GFP_ATOMIC);
153 if (!mp)
154 goto bail;
155
156 em->msg = mp;
157 em->flags |= EMFL_VALID;
158 em->len = n;
159
160 emsgs_tail_idx++;
161 emsgs_tail_idx %= ARRAY_SIZE(emsgs);
162
163 spin_unlock_irqrestore(&emsgs_lock, flags);
164
165 if (nblocked_emsgs_readers)
166 complete(&emsgs_comp);
167}
168
169static ssize_t
170aoechr_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offp)
171{
172 int ret = -EINVAL;
173
174 switch ((unsigned long) filp->private_data) {
175 default:
176 printk(KERN_INFO "aoe: can't write to that file.\n");
177 break;
178 case MINOR_DISCOVER:
179 ret = discover();
180 break;
181 case MINOR_INTERFACES:
182 ret = interfaces(buf, cnt);
183 break;
184 case MINOR_REVALIDATE:
185 ret = revalidate(buf, cnt);
186 break;
187 case MINOR_FLUSH:
188 ret = aoedev_flush(buf, cnt);
189 break;
190 }
191 if (ret == 0)
192 ret = cnt;
193 return ret;
194}
195
196static int
197aoechr_open(struct inode *inode, struct file *filp)
198{
199 int n, i;
200
201 mutex_lock(&aoechr_mutex);
202 n = iminor(inode);
203 filp->private_data = (void *) (unsigned long) n;
204
205 for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
206 if (chardevs[i].minor == n) {
207 mutex_unlock(&aoechr_mutex);
208 return 0;
209 }
210 mutex_unlock(&aoechr_mutex);
211 return -EINVAL;
212}
213
214static int
215aoechr_rel(struct inode *inode, struct file *filp)
216{
217 return 0;
218}
219
220static ssize_t
221aoechr_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off)
222{
223 unsigned long n;
224 char *mp;
225 struct ErrMsg *em;
226 ssize_t len;
227 ulong flags;
228
229 n = (unsigned long) filp->private_data;
230 if (n != MINOR_ERR)
231 return -EFAULT;
232
233 spin_lock_irqsave(&emsgs_lock, flags);
234
235 for (;;) {
236 em = emsgs + emsgs_head_idx;
237 if ((em->flags & EMFL_VALID) != 0)
238 break;
239 if (filp->f_flags & O_NDELAY) {
240 spin_unlock_irqrestore(&emsgs_lock, flags);
241 return -EAGAIN;
242 }
243 nblocked_emsgs_readers++;
244
245 spin_unlock_irqrestore(&emsgs_lock, flags);
246
247 n = wait_for_completion_interruptible(&emsgs_comp);
248
249 spin_lock_irqsave(&emsgs_lock, flags);
250
251 nblocked_emsgs_readers--;
252
253 if (n) {
254 spin_unlock_irqrestore(&emsgs_lock, flags);
255 return -ERESTARTSYS;
256 }
257 }
258 if (em->len > cnt) {
259 spin_unlock_irqrestore(&emsgs_lock, flags);
260 return -EAGAIN;
261 }
262 mp = em->msg;
263 len = em->len;
264 em->msg = NULL;
265 em->flags &= ~EMFL_VALID;
266
267 emsgs_head_idx++;
268 emsgs_head_idx %= ARRAY_SIZE(emsgs);
269
270 spin_unlock_irqrestore(&emsgs_lock, flags);
271
272 n = copy_to_user(buf, mp, len);
273 kfree(mp);
274 return n == 0 ? len : -EFAULT;
275}
276
277static const struct file_operations aoe_fops = {
278 .write = aoechr_write,
279 .read = aoechr_read,
280 .open = aoechr_open,
281 .release = aoechr_rel,
282 .owner = THIS_MODULE,
283 .llseek = noop_llseek,
284};
285
286int __init
287aoechr_init(void)
288{
289 int n, i;
290
291 n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops);
292 if (n < 0) {
293 printk(KERN_ERR "aoe: can't register char device\n");
294 return n;
295 }
296 init_completion(&emsgs_comp);
297 spin_lock_init(&emsgs_lock);
298 n = class_register(&aoe_class);
299 if (n) {
300 unregister_chrdev(AOE_MAJOR, "aoechr");
301 return n;
302 }
303
304 for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
305 device_create(&aoe_class, NULL,
306 MKDEV(AOE_MAJOR, chardevs[i].minor), NULL,
307 chardevs[i].name);
308
309 return 0;
310}
311
312void
313aoechr_exit(void)
314{
315 int i;
316
317 for (i = 0; i < ARRAY_SIZE(chardevs); ++i)
318 device_destroy(&aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
319 class_unregister(&aoe_class);
320 unregister_chrdev(AOE_MAJOR, "aoechr");
321}
322