Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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; |
gregkh@suse.de | deb3697 | 2005-03-23 09:52:10 -0800 | [diff] [blame] | 39 | static struct class *aoe_class; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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); |
gregkh@suse.de | deb3697 | 2005-03-23 09:52:10 -0800 | [diff] [blame] | 221 | aoe_class = class_create(THIS_MODULE, "aoe"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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) |
Greg Kroah-Hartman | 53f4654 | 2005-10-27 22:25:43 -0700 | [diff] [blame^] | 227 | class_device_create(aoe_class, NULL, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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) |
gregkh@suse.de | deb3697 | 2005-03-23 09:52:10 -0800 | [diff] [blame] | 240 | class_device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor)); |
| 241 | class_destroy(aoe_class); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | unregister_chrdev(AOE_MAJOR, "aoechr"); |
| 243 | } |
| 244 | |