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 MINOR_REVALIDATE, 17 MSGSZ = 2048, 18 NARGS = 10, 19 NMSG = 100, /* message backlog to retain */ 20 }; 21 22 struct aoe_chardev { 23 ulong minor; 24 char name[32]; 25 }; 26 27 enum { EMFL_VALID = 1 }; 28 29 struct ErrMsg { 30 short flags; 31 short len; 32 char *msg; 33 }; 34 35 static struct ErrMsg emsgs[NMSG]; 36 static int emsgs_head_idx, emsgs_tail_idx; 37 static struct semaphore emsgs_sema; 38 static spinlock_t emsgs_lock; 39 static int nblocked_emsgs_readers; 40 static struct class *aoe_class; 41 static struct aoe_chardev chardevs[] = { 42 { MINOR_ERR, "err" }, 43 { MINOR_DISCOVER, "discover" }, 44 { MINOR_INTERFACES, "interfaces" }, 45 { MINOR_REVALIDATE, "revalidate" }, 46 }; 47 48 static int 49 discover(void) 50 { 51 aoecmd_cfg(0xffff, 0xff); 52 return 0; 53 } 54 55 static int 56 interfaces(const char __user *str, size_t size) 57 { 58 if (set_aoe_iflist(str, size)) { 59 printk(KERN_CRIT 60 "%s: could not set interface list: %s\n", 61 __FUNCTION__, "too many interfaces"); 62 return -EINVAL; 63 } 64 return 0; 65 } 66 67 static int 68 revalidate(const char __user *str, size_t size) 69 { 70 int major, minor, n; 71 ulong flags; 72 struct aoedev *d; 73 char buf[16]; 74 75 if (size >= sizeof buf) 76 return -EINVAL; 77 buf[sizeof buf - 1] = '\0'; 78 if (copy_from_user(buf, str, size)) 79 return -EFAULT; 80 81 /* should be e%d.%d format */ 82 n = sscanf(buf, "e%d.%d", &major, &minor); 83 if (n != 2) { 84 printk(KERN_ERR "aoe: %s: invalid device specification\n", 85 __FUNCTION__); 86 return -EINVAL; 87 } 88 d = aoedev_by_aoeaddr(major, minor); 89 if (!d) 90 return -EINVAL; 91 92 spin_lock_irqsave(&d->lock, flags); 93 d->flags |= DEVFL_PAUSE; 94 spin_unlock_irqrestore(&d->lock, flags); 95 aoecmd_cfg(major, minor); 96 97 return 0; 98 } 99 100 void 101 aoechr_error(char *msg) 102 { 103 struct ErrMsg *em; 104 char *mp; 105 ulong flags, n; 106 107 n = strlen(msg); 108 109 spin_lock_irqsave(&emsgs_lock, flags); 110 111 em = emsgs + emsgs_tail_idx; 112 if ((em->flags & EMFL_VALID)) { 113 bail: spin_unlock_irqrestore(&emsgs_lock, flags); 114 return; 115 } 116 117 mp = kmalloc(n, GFP_ATOMIC); 118 if (mp == NULL) { 119 printk(KERN_CRIT "aoe: aoechr_error: allocation failure, len=%ld\n", n); 120 goto bail; 121 } 122 123 memcpy(mp, msg, n); 124 em->msg = mp; 125 em->flags |= EMFL_VALID; 126 em->len = n; 127 128 emsgs_tail_idx++; 129 emsgs_tail_idx %= ARRAY_SIZE(emsgs); 130 131 spin_unlock_irqrestore(&emsgs_lock, flags); 132 133 if (nblocked_emsgs_readers) 134 up(&emsgs_sema); 135 } 136 137 static ssize_t 138 aoechr_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offp) 139 { 140 int ret = -EINVAL; 141 142 switch ((unsigned long) filp->private_data) { 143 default: 144 printk(KERN_INFO "aoe: aoechr_write: can't write to that file.\n"); 145 break; 146 case MINOR_DISCOVER: 147 ret = discover(); 148 break; 149 case MINOR_INTERFACES: 150 ret = interfaces(buf, cnt); 151 break; 152 case MINOR_REVALIDATE: 153 ret = revalidate(buf, cnt); 154 } 155 if (ret == 0) 156 ret = cnt; 157 return ret; 158 } 159 160 static int 161 aoechr_open(struct inode *inode, struct file *filp) 162 { 163 int n, i; 164 165 n = MINOR(inode->i_rdev); 166 filp->private_data = (void *) (unsigned long) n; 167 168 for (i = 0; i < ARRAY_SIZE(chardevs); ++i) 169 if (chardevs[i].minor == n) 170 return 0; 171 return -EINVAL; 172 } 173 174 static int 175 aoechr_rel(struct inode *inode, struct file *filp) 176 { 177 return 0; 178 } 179 180 static ssize_t 181 aoechr_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off) 182 { 183 unsigned long n; 184 char *mp; 185 struct ErrMsg *em; 186 ssize_t len; 187 ulong flags; 188 189 n = (unsigned long) filp->private_data; 190 switch (n) { 191 case MINOR_ERR: 192 spin_lock_irqsave(&emsgs_lock, flags); 193 loop: 194 em = emsgs + emsgs_head_idx; 195 if ((em->flags & EMFL_VALID) == 0) { 196 if (filp->f_flags & O_NDELAY) { 197 spin_unlock_irqrestore(&emsgs_lock, flags); 198 return -EAGAIN; 199 } 200 nblocked_emsgs_readers++; 201 202 spin_unlock_irqrestore(&emsgs_lock, flags); 203 204 n = down_interruptible(&emsgs_sema); 205 206 spin_lock_irqsave(&emsgs_lock, flags); 207 208 nblocked_emsgs_readers--; 209 210 if (n) { 211 spin_unlock_irqrestore(&emsgs_lock, flags); 212 return -ERESTARTSYS; 213 } 214 goto loop; 215 } 216 if (em->len > cnt) { 217 spin_unlock_irqrestore(&emsgs_lock, flags); 218 return -EAGAIN; 219 } 220 mp = em->msg; 221 len = em->len; 222 em->msg = NULL; 223 em->flags &= ~EMFL_VALID; 224 225 emsgs_head_idx++; 226 emsgs_head_idx %= ARRAY_SIZE(emsgs); 227 228 spin_unlock_irqrestore(&emsgs_lock, flags); 229 230 n = copy_to_user(buf, mp, len); 231 kfree(mp); 232 return n == 0 ? len : -EFAULT; 233 default: 234 return -EFAULT; 235 } 236 } 237 238 static struct file_operations aoe_fops = { 239 .write = aoechr_write, 240 .read = aoechr_read, 241 .open = aoechr_open, 242 .release = aoechr_rel, 243 .owner = THIS_MODULE, 244 }; 245 246 int __init 247 aoechr_init(void) 248 { 249 int n, i; 250 251 n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops); 252 if (n < 0) { 253 printk(KERN_ERR "aoe: aoechr_init: can't register char device\n"); 254 return n; 255 } 256 sema_init(&emsgs_sema, 0); 257 spin_lock_init(&emsgs_lock); 258 aoe_class = class_create(THIS_MODULE, "aoe"); 259 if (IS_ERR(aoe_class)) { 260 unregister_chrdev(AOE_MAJOR, "aoechr"); 261 return PTR_ERR(aoe_class); 262 } 263 for (i = 0; i < ARRAY_SIZE(chardevs); ++i) 264 class_device_create(aoe_class, NULL, 265 MKDEV(AOE_MAJOR, chardevs[i].minor), 266 NULL, chardevs[i].name); 267 268 return 0; 269 } 270 271 void 272 aoechr_exit(void) 273 { 274 int i; 275 276 for (i = 0; i < ARRAY_SIZE(chardevs); ++i) 277 class_device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor)); 278 class_destroy(aoe_class); 279 unregister_chrdev(AOE_MAJOR, "aoechr"); 280 } 281 282