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Commit | Line | Data |
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fea05a26 | 1 | /* Copyright (c) 2012 Coraid, Inc. See COPYING for GPL terms. */ |
1da177e4 LT |
2 | /* |
3 | * aoechr.c | |
4 | * AoE character device driver | |
5 | */ | |
6 | ||
7 | #include <linux/hdreg.h> | |
8 | #include <linux/blkdev.h> | |
24879a8e | 9 | #include <linux/completion.h> |
68e0d42f | 10 | #include <linux/delay.h> |
5a0e3ad6 | 11 | #include <linux/slab.h> |
2a48fc0a | 12 | #include <linux/mutex.h> |
e9bb8fb0 | 13 | #include <linux/skbuff.h> |
d5decd3b | 14 | #include <linux/export.h> |
1da177e4 LT |
15 | #include "aoe.h" |
16 | ||
17 | enum { | |
18 | //MINOR_STAT = 1, (moved to sysfs) | |
19 | MINOR_ERR = 2, | |
20 | MINOR_DISCOVER, | |
21 | MINOR_INTERFACES, | |
3ae1c24e | 22 | MINOR_REVALIDATE, |
262bf541 | 23 | MINOR_FLUSH, |
1da177e4 | 24 | MSGSZ = 2048, |
1da177e4 LT |
25 | NMSG = 100, /* message backlog to retain */ |
26 | }; | |
27 | ||
28 | struct aoe_chardev { | |
29 | ulong minor; | |
30 | char name[32]; | |
31 | }; | |
32 | ||
33 | enum { EMFL_VALID = 1 }; | |
34 | ||
35 | struct ErrMsg { | |
36 | short flags; | |
37 | short len; | |
38 | char *msg; | |
39 | }; | |
40 | ||
2a48fc0a | 41 | static DEFINE_MUTEX(aoechr_mutex); |
662a8896 EC |
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 | */ | |
1da177e4 LT |
47 | static struct ErrMsg emsgs[NMSG]; |
48 | static int emsgs_head_idx, emsgs_tail_idx; | |
24879a8e | 49 | static struct completion emsgs_comp; |
1da177e4 LT |
50 | static spinlock_t emsgs_lock; |
51 | static int nblocked_emsgs_readers; | |
deb36970 | 52 | static struct class *aoe_class; |
1da177e4 LT |
53 | static struct aoe_chardev chardevs[] = { |
54 | { MINOR_ERR, "err" }, | |
55 | { MINOR_DISCOVER, "discover" }, | |
56 | { MINOR_INTERFACES, "interfaces" }, | |
3ae1c24e | 57 | { MINOR_REVALIDATE, "revalidate" }, |
262bf541 | 58 | { MINOR_FLUSH, "flush" }, |
1da177e4 LT |
59 | }; |
60 | ||
61 | static int | |
62 | discover(void) | |
63 | { | |
64 | aoecmd_cfg(0xffff, 0xff); | |
65 | return 0; | |
66 | } | |
67 | ||
68 | static int | |
69 | interfaces(const char __user *str, size_t size) | |
70 | { | |
71 | if (set_aoe_iflist(str, size)) { | |
a12c93f0 EC |
72 | printk(KERN_ERR |
73 | "aoe: could not set interface list: too many interfaces\n"); | |
1da177e4 LT |
74 | return -EINVAL; |
75 | } | |
76 | return 0; | |
77 | } | |
78 | ||
3ae1c24e EC |
79 | static int |
80 | revalidate(const char __user *str, size_t size) | |
81 | { | |
82 | int major, minor, n; | |
83 | ulong flags; | |
84 | struct aoedev *d; | |
68e0d42f | 85 | struct sk_buff *skb; |
3ae1c24e EC |
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 | ||
3ae1c24e EC |
94 | n = sscanf(buf, "e%d.%d", &major, &minor); |
95 | if (n != 2) { | |
896831f5 | 96 | pr_err("aoe: invalid device specification %s\n", buf); |
3ae1c24e EC |
97 | return -EINVAL; |
98 | } | |
0c966214 | 99 | d = aoedev_by_aoeaddr(major, minor, 0); |
3ae1c24e EC |
100 | if (!d) |
101 | return -EINVAL; | |
3ae1c24e | 102 | spin_lock_irqsave(&d->lock, flags); |
68e0d42f | 103 | aoecmd_cleanslate(d); |
25f4d75e | 104 | aoecmd_cfg(major, minor); |
68e0d42f EC |
105 | loop: |
106 | skb = aoecmd_ata_id(d); | |
3ae1c24e | 107 | spin_unlock_irqrestore(&d->lock, flags); |
68e0d42f EC |
108 | /* try again if we are able to sleep a bit, |
109 | * otherwise give up this revalidation | |
110 | */ | |
25f4d75e | 111 | if (!skb && !msleep_interruptible(250)) { |
68e0d42f EC |
112 | spin_lock_irqsave(&d->lock, flags); |
113 | goto loop; | |
114 | } | |
69cf2d85 | 115 | aoedev_put(d); |
e9bb8fb0 DM |
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 | } | |
3ae1c24e EC |
122 | return 0; |
123 | } | |
124 | ||
1da177e4 LT |
125 | void |
126 | aoechr_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)) { | |
138 | bail: spin_unlock_irqrestore(&emsgs_lock, flags); | |
139 | return; | |
140 | } | |
141 | ||
60abc786 | 142 | mp = kmemdup(msg, n, GFP_ATOMIC); |
1da177e4 | 143 | if (mp == NULL) { |
a12c93f0 | 144 | printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n); |
1da177e4 LT |
145 | goto bail; |
146 | } | |
147 | ||
1da177e4 LT |
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) | |
24879a8e | 158 | complete(&emsgs_comp); |
1da177e4 LT |
159 | } |
160 | ||
161 | static ssize_t | |
162 | aoechr_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: | |
a12c93f0 | 168 | printk(KERN_INFO "aoe: can't write to that file.\n"); |
1da177e4 LT |
169 | break; |
170 | case MINOR_DISCOVER: | |
171 | ret = discover(); | |
172 | break; | |
173 | case MINOR_INTERFACES: | |
174 | ret = interfaces(buf, cnt); | |
175 | break; | |
3ae1c24e EC |
176 | case MINOR_REVALIDATE: |
177 | ret = revalidate(buf, cnt); | |
262bf541 EC |
178 | break; |
179 | case MINOR_FLUSH: | |
180 | ret = aoedev_flush(buf, cnt); | |
b21faa25 | 181 | break; |
1da177e4 LT |
182 | } |
183 | if (ret == 0) | |
184 | ret = cnt; | |
185 | return ret; | |
186 | } | |
187 | ||
188 | static int | |
189 | aoechr_open(struct inode *inode, struct file *filp) | |
190 | { | |
191 | int n, i; | |
192 | ||
2a48fc0a | 193 | mutex_lock(&aoechr_mutex); |
2017b376 | 194 | n = iminor(inode); |
1da177e4 LT |
195 | filp->private_data = (void *) (unsigned long) n; |
196 | ||
197 | for (i = 0; i < ARRAY_SIZE(chardevs); ++i) | |
579174a5 | 198 | if (chardevs[i].minor == n) { |
2a48fc0a | 199 | mutex_unlock(&aoechr_mutex); |
1da177e4 | 200 | return 0; |
579174a5 | 201 | } |
2a48fc0a | 202 | mutex_unlock(&aoechr_mutex); |
1da177e4 LT |
203 | return -EINVAL; |
204 | } | |
205 | ||
206 | static int | |
207 | aoechr_rel(struct inode *inode, struct file *filp) | |
208 | { | |
209 | return 0; | |
210 | } | |
211 | ||
212 | static ssize_t | |
213 | aoechr_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; | |
cf446f0d EC |
222 | if (n != MINOR_ERR) |
223 | return -EFAULT; | |
224 | ||
225 | spin_lock_irqsave(&emsgs_lock, flags); | |
1da177e4 | 226 | |
cf446f0d EC |
227 | for (;;) { |
228 | em = emsgs + emsgs_head_idx; | |
229 | if ((em->flags & EMFL_VALID) != 0) | |
230 | break; | |
231 | if (filp->f_flags & O_NDELAY) { | |
1da177e4 | 232 | spin_unlock_irqrestore(&emsgs_lock, flags); |
cf446f0d EC |
233 | return -EAGAIN; |
234 | } | |
235 | nblocked_emsgs_readers++; | |
236 | ||
237 | spin_unlock_irqrestore(&emsgs_lock, flags); | |
1da177e4 | 238 | |
24879a8e | 239 | n = wait_for_completion_interruptible(&emsgs_comp); |
1da177e4 | 240 | |
cf446f0d | 241 | spin_lock_irqsave(&emsgs_lock, flags); |
1da177e4 | 242 | |
cf446f0d | 243 | nblocked_emsgs_readers--; |
1da177e4 | 244 | |
cf446f0d | 245 | if (n) { |
1da177e4 | 246 | spin_unlock_irqrestore(&emsgs_lock, flags); |
cf446f0d | 247 | return -ERESTARTSYS; |
1da177e4 | 248 | } |
cf446f0d EC |
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; | |
1da177e4 | 258 | |
cf446f0d EC |
259 | emsgs_head_idx++; |
260 | emsgs_head_idx %= ARRAY_SIZE(emsgs); | |
1da177e4 | 261 | |
cf446f0d | 262 | spin_unlock_irqrestore(&emsgs_lock, flags); |
1da177e4 | 263 | |
cf446f0d EC |
264 | n = copy_to_user(buf, mp, len); |
265 | kfree(mp); | |
266 | return n == 0 ? len : -EFAULT; | |
1da177e4 LT |
267 | } |
268 | ||
2b8693c0 | 269 | static const struct file_operations aoe_fops = { |
1da177e4 LT |
270 | .write = aoechr_write, |
271 | .read = aoechr_read, | |
272 | .open = aoechr_open, | |
273 | .release = aoechr_rel, | |
274 | .owner = THIS_MODULE, | |
6038f373 | 275 | .llseek = noop_llseek, |
1da177e4 LT |
276 | }; |
277 | ||
2c9ede55 | 278 | static char *aoe_devnode(struct device *dev, umode_t *mode) |
1ce8a0d3 KS |
279 | { |
280 | return kasprintf(GFP_KERNEL, "etherd/%s", dev_name(dev)); | |
281 | } | |
282 | ||
1da177e4 LT |
283 | int __init |
284 | aoechr_init(void) | |
285 | { | |
286 | int n, i; | |
287 | ||
288 | n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops); | |
a04b41cd | 289 | if (n < 0) { |
a12c93f0 | 290 | printk(KERN_ERR "aoe: can't register char device\n"); |
1da177e4 LT |
291 | return n; |
292 | } | |
24879a8e | 293 | init_completion(&emsgs_comp); |
1da177e4 | 294 | spin_lock_init(&emsgs_lock); |
deb36970 | 295 | aoe_class = class_create(THIS_MODULE, "aoe"); |
1da177e4 LT |
296 | if (IS_ERR(aoe_class)) { |
297 | unregister_chrdev(AOE_MAJOR, "aoechr"); | |
298 | return PTR_ERR(aoe_class); | |
299 | } | |
e454cea2 | 300 | aoe_class->devnode = aoe_devnode; |
1ce8a0d3 | 301 | |
1da177e4 | 302 | for (i = 0; i < ARRAY_SIZE(chardevs); ++i) |
1ff9f542 GKH |
303 | device_create(aoe_class, NULL, |
304 | MKDEV(AOE_MAJOR, chardevs[i].minor), NULL, | |
305 | chardevs[i].name); | |
1da177e4 LT |
306 | |
307 | return 0; | |
308 | } | |
309 | ||
310 | void | |
311 | aoechr_exit(void) | |
312 | { | |
313 | int i; | |
314 | ||
315 | for (i = 0; i < ARRAY_SIZE(chardevs); ++i) | |
7ea7ed01 | 316 | device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor)); |
deb36970 | 317 | class_destroy(aoe_class); |
1da177e4 LT |
318 | unregister_chrdev(AOE_MAJOR, "aoechr"); |
319 | } | |
320 |