[PATCH] class: convert drivers/block/* to use the new class api instead of class_simple
[linux-2.6.git] / drivers / block / aoe / aoechr.c
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 *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_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_device_create(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_device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor));
241         class_destroy(aoe_class);
242         unregister_chrdev(AOE_MAJOR, "aoechr");
243 }
244