]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* Copyright (c) 2004 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 "aoe.h" | |
10 | ||
11 | enum { | |
12 | //MINOR_STAT = 1, (moved to sysfs) | |
13 | MINOR_ERR = 2, | |
14 | MINOR_DISCOVER, | |
15 | MINOR_INTERFACES, | |
16 | MSGSZ = 2048, | |
17 | NARGS = 10, | |
18 | NMSG = 100, /* message backlog to retain */ | |
19 | }; | |
20 | ||
21 | struct aoe_chardev { | |
22 | ulong minor; | |
23 | char name[32]; | |
24 | }; | |
25 | ||
26 | enum { EMFL_VALID = 1 }; | |
27 | ||
28 | struct ErrMsg { | |
29 | short flags; | |
30 | short len; | |
31 | char *msg; | |
32 | }; | |
33 | ||
34 | static struct ErrMsg emsgs[NMSG]; | |
35 | static int emsgs_head_idx, emsgs_tail_idx; | |
36 | static struct semaphore emsgs_sema; | |
37 | static spinlock_t emsgs_lock; | |
38 | static int nblocked_emsgs_readers; | |
39 | static struct class_simple *aoe_class; | |
40 | static struct aoe_chardev chardevs[] = { | |
41 | { MINOR_ERR, "err" }, | |
42 | { MINOR_DISCOVER, "discover" }, | |
43 | { MINOR_INTERFACES, "interfaces" }, | |
44 | }; | |
45 | ||
46 | static int | |
47 | discover(void) | |
48 | { | |
49 | aoecmd_cfg(0xffff, 0xff); | |
50 | return 0; | |
51 | } | |
52 | ||
53 | static int | |
54 | interfaces(const char __user *str, size_t size) | |
55 | { | |
56 | if (set_aoe_iflist(str, size)) { | |
57 | printk(KERN_CRIT | |
58 | "%s: could not set interface list: %s\n", | |
59 | __FUNCTION__, "too many interfaces"); | |
60 | return -EINVAL; | |
61 | } | |
62 | return 0; | |
63 | } | |
64 | ||
65 | void | |
66 | aoechr_error(char *msg) | |
67 | { | |
68 | struct ErrMsg *em; | |
69 | char *mp; | |
70 | ulong flags, n; | |
71 | ||
72 | n = strlen(msg); | |
73 | ||
74 | spin_lock_irqsave(&emsgs_lock, flags); | |
75 | ||
76 | em = emsgs + emsgs_tail_idx; | |
77 | if ((em->flags & EMFL_VALID)) { | |
78 | bail: spin_unlock_irqrestore(&emsgs_lock, flags); | |
79 | return; | |
80 | } | |
81 | ||
82 | mp = kmalloc(n, GFP_ATOMIC); | |
83 | if (mp == NULL) { | |
84 | printk(KERN_CRIT "aoe: aoechr_error: allocation failure, len=%ld\n", n); | |
85 | goto bail; | |
86 | } | |
87 | ||
88 | memcpy(mp, msg, n); | |
89 | em->msg = mp; | |
90 | em->flags |= EMFL_VALID; | |
91 | em->len = n; | |
92 | ||
93 | emsgs_tail_idx++; | |
94 | emsgs_tail_idx %= ARRAY_SIZE(emsgs); | |
95 | ||
96 | spin_unlock_irqrestore(&emsgs_lock, flags); | |
97 | ||
98 | if (nblocked_emsgs_readers) | |
99 | up(&emsgs_sema); | |
100 | } | |
101 | ||
102 | static ssize_t | |
103 | aoechr_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offp) | |
104 | { | |
105 | int ret = -EINVAL; | |
106 | ||
107 | switch ((unsigned long) filp->private_data) { | |
108 | default: | |
109 | printk(KERN_INFO "aoe: aoechr_write: can't write to that file.\n"); | |
110 | break; | |
111 | case MINOR_DISCOVER: | |
112 | ret = discover(); | |
113 | break; | |
114 | case MINOR_INTERFACES: | |
115 | ret = interfaces(buf, cnt); | |
116 | break; | |
117 | } | |
118 | if (ret == 0) | |
119 | ret = cnt; | |
120 | return ret; | |
121 | } | |
122 | ||
123 | static int | |
124 | aoechr_open(struct inode *inode, struct file *filp) | |
125 | { | |
126 | int n, i; | |
127 | ||
128 | n = MINOR(inode->i_rdev); | |
129 | filp->private_data = (void *) (unsigned long) n; | |
130 | ||
131 | for (i = 0; i < ARRAY_SIZE(chardevs); ++i) | |
132 | if (chardevs[i].minor == n) | |
133 | return 0; | |
134 | return -EINVAL; | |
135 | } | |
136 | ||
137 | static int | |
138 | aoechr_rel(struct inode *inode, struct file *filp) | |
139 | { | |
140 | return 0; | |
141 | } | |
142 | ||
143 | static ssize_t | |
144 | aoechr_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off) | |
145 | { | |
146 | unsigned long n; | |
147 | char *mp; | |
148 | struct ErrMsg *em; | |
149 | ssize_t len; | |
150 | ulong flags; | |
151 | ||
152 | n = (unsigned long) filp->private_data; | |
153 | switch (n) { | |
154 | case MINOR_ERR: | |
155 | spin_lock_irqsave(&emsgs_lock, flags); | |
156 | loop: | |
157 | em = emsgs + emsgs_head_idx; | |
158 | if ((em->flags & EMFL_VALID) == 0) { | |
159 | if (filp->f_flags & O_NDELAY) { | |
160 | spin_unlock_irqrestore(&emsgs_lock, flags); | |
161 | return -EAGAIN; | |
162 | } | |
163 | nblocked_emsgs_readers++; | |
164 | ||
165 | spin_unlock_irqrestore(&emsgs_lock, flags); | |
166 | ||
167 | n = down_interruptible(&emsgs_sema); | |
168 | ||
169 | spin_lock_irqsave(&emsgs_lock, flags); | |
170 | ||
171 | nblocked_emsgs_readers--; | |
172 | ||
173 | if (n) { | |
174 | spin_unlock_irqrestore(&emsgs_lock, flags); | |
175 | return -ERESTARTSYS; | |
176 | } | |
177 | goto loop; | |
178 | } | |
179 | if (em->len > cnt) { | |
180 | spin_unlock_irqrestore(&emsgs_lock, flags); | |
181 | return -EAGAIN; | |
182 | } | |
183 | mp = em->msg; | |
184 | len = em->len; | |
185 | em->msg = NULL; | |
186 | em->flags &= ~EMFL_VALID; | |
187 | ||
188 | emsgs_head_idx++; | |
189 | emsgs_head_idx %= ARRAY_SIZE(emsgs); | |
190 | ||
191 | spin_unlock_irqrestore(&emsgs_lock, flags); | |
192 | ||
193 | n = copy_to_user(buf, mp, len); | |
194 | kfree(mp); | |
195 | return n == 0 ? len : -EFAULT; | |
196 | default: | |
197 | return -EFAULT; | |
198 | } | |
199 | } | |
200 | ||
201 | static struct file_operations aoe_fops = { | |
202 | .write = aoechr_write, | |
203 | .read = aoechr_read, | |
204 | .open = aoechr_open, | |
205 | .release = aoechr_rel, | |
206 | .owner = THIS_MODULE, | |
207 | }; | |
208 | ||
209 | int __init | |
210 | aoechr_init(void) | |
211 | { | |
212 | int n, i; | |
213 | ||
214 | n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops); | |
215 | if (n < 0) { | |
216 | printk(KERN_ERR "aoe: aoechr_init: can't register char device\n"); | |
217 | return n; | |
218 | } | |
219 | sema_init(&emsgs_sema, 0); | |
220 | spin_lock_init(&emsgs_lock); | |
221 | aoe_class = class_simple_create(THIS_MODULE, "aoe"); | |
222 | if (IS_ERR(aoe_class)) { | |
223 | unregister_chrdev(AOE_MAJOR, "aoechr"); | |
224 | return PTR_ERR(aoe_class); | |
225 | } | |
226 | for (i = 0; i < ARRAY_SIZE(chardevs); ++i) | |
227 | class_simple_device_add(aoe_class, | |
228 | MKDEV(AOE_MAJOR, chardevs[i].minor), | |
229 | NULL, chardevs[i].name); | |
230 | ||
231 | return 0; | |
232 | } | |
233 | ||
234 | void | |
235 | aoechr_exit(void) | |
236 | { | |
237 | int i; | |
238 | ||
239 | for (i = 0; i < ARRAY_SIZE(chardevs); ++i) | |
240 | class_simple_device_remove(MKDEV(AOE_MAJOR, chardevs[i].minor)); | |
241 | class_simple_destroy(aoe_class); | |
242 | unregister_chrdev(AOE_MAJOR, "aoechr"); | |
243 | } | |
244 |