1 /* Copyright (c) 2007 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 <linux/delay.h> 10 #include "aoe.h" 11 12 enum { 13 //MINOR_STAT = 1, (moved to sysfs) 14 MINOR_ERR = 2, 15 MINOR_DISCOVER, 16 MINOR_INTERFACES, 17 MINOR_REVALIDATE, 18 MINOR_FLUSH, 19 MSGSZ = 2048, 20 NMSG = 100, /* message backlog to retain */ 21 }; 22 23 struct aoe_chardev { 24 ulong minor; 25 char name[32]; 26 }; 27 28 enum { EMFL_VALID = 1 }; 29 30 struct ErrMsg { 31 short flags; 32 short len; 33 char *msg; 34 }; 35 36 static struct ErrMsg emsgs[NMSG]; 37 static int emsgs_head_idx, emsgs_tail_idx; 38 static struct semaphore emsgs_sema; 39 static spinlock_t emsgs_lock; 40 static int nblocked_emsgs_readers; 41 static struct class *aoe_class; 42 static struct aoe_chardev chardevs[] = { 43 { MINOR_ERR, "err" }, 44 { MINOR_DISCOVER, "discover" }, 45 { MINOR_INTERFACES, "interfaces" }, 46 { MINOR_REVALIDATE, "revalidate" }, 47 { MINOR_FLUSH, "flush" }, 48 }; 49 50 static int 51 discover(void) 52 { 53 aoecmd_cfg(0xffff, 0xff); 54 return 0; 55 } 56 57 static int 58 interfaces(const char __user *str, size_t size) 59 { 60 if (set_aoe_iflist(str, size)) { 61 printk(KERN_ERR 62 "aoe: could not set interface list: too many interfaces\n"); 63 return -EINVAL; 64 } 65 return 0; 66 } 67 68 static int 69 revalidate(const char __user *str, size_t size) 70 { 71 int major, minor, n; 72 ulong flags; 73 struct aoedev *d; 74 struct sk_buff *skb; 75 char buf[16]; 76 77 if (size >= sizeof buf) 78 return -EINVAL; 79 buf[sizeof buf - 1] = '\0'; 80 if (copy_from_user(buf, str, size)) 81 return -EFAULT; 82 83 /* should be e%d.%d format */ 84 n = sscanf(buf, "e%d.%d", &major, &minor); 85 if (n != 2) { 86 printk(KERN_ERR "aoe: invalid device specification\n"); 87 return -EINVAL; 88 } 89 d = aoedev_by_aoeaddr(major, minor); 90 if (!d) 91 return -EINVAL; 92 spin_lock_irqsave(&d->lock, flags); 93 aoecmd_cleanslate(d); 94 loop: 95 skb = aoecmd_ata_id(d); 96 spin_unlock_irqrestore(&d->lock, flags); 97 /* try again if we are able to sleep a bit, 98 * otherwise give up this revalidation 99 */ 100 if (!skb && !msleep_interruptible(200)) { 101 spin_lock_irqsave(&d->lock, flags); 102 goto loop; 103 } 104 aoenet_xmit(skb); 105 aoecmd_cfg(major, minor); 106 return 0; 107 } 108 109 void 110 aoechr_error(char *msg) 111 { 112 struct ErrMsg *em; 113 char *mp; 114 ulong flags, n; 115 116 n = strlen(msg); 117 118 spin_lock_irqsave(&emsgs_lock, flags); 119 120 em = emsgs + emsgs_tail_idx; 121 if ((em->flags & EMFL_VALID)) { 122 bail: spin_unlock_irqrestore(&emsgs_lock, flags); 123 return; 124 } 125 126 mp = kmalloc(n, GFP_ATOMIC); 127 if (mp == NULL) { 128 printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n); 129 goto bail; 130 } 131 132 memcpy(mp, msg, n); 133 em->msg = mp; 134 em->flags |= EMFL_VALID; 135 em->len = n; 136 137 emsgs_tail_idx++; 138 emsgs_tail_idx %= ARRAY_SIZE(emsgs); 139 140 spin_unlock_irqrestore(&emsgs_lock, flags); 141 142 if (nblocked_emsgs_readers) 143 up(&emsgs_sema); 144 } 145 146 static ssize_t 147 aoechr_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offp) 148 { 149 int ret = -EINVAL; 150 151 switch ((unsigned long) filp->private_data) { 152 default: 153 printk(KERN_INFO "aoe: can't write to that file.\n"); 154 break; 155 case MINOR_DISCOVER: 156 ret = discover(); 157 break; 158 case MINOR_INTERFACES: 159 ret = interfaces(buf, cnt); 160 break; 161 case MINOR_REVALIDATE: 162 ret = revalidate(buf, cnt); 163 break; 164 case MINOR_FLUSH: 165 ret = aoedev_flush(buf, cnt); 166 } 167 if (ret == 0) 168 ret = cnt; 169 return ret; 170 } 171 172 static int 173 aoechr_open(struct inode *inode, struct file *filp) 174 { 175 int n, i; 176 177 n = iminor(inode); 178 filp->private_data = (void *) (unsigned long) n; 179 180 for (i = 0; i < ARRAY_SIZE(chardevs); ++i) 181 if (chardevs[i].minor == n) 182 return 0; 183 return -EINVAL; 184 } 185 186 static int 187 aoechr_rel(struct inode *inode, struct file *filp) 188 { 189 return 0; 190 } 191 192 static ssize_t 193 aoechr_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off) 194 { 195 unsigned long n; 196 char *mp; 197 struct ErrMsg *em; 198 ssize_t len; 199 ulong flags; 200 201 n = (unsigned long) filp->private_data; 202 if (n != MINOR_ERR) 203 return -EFAULT; 204 205 spin_lock_irqsave(&emsgs_lock, flags); 206 207 for (;;) { 208 em = emsgs + emsgs_head_idx; 209 if ((em->flags & EMFL_VALID) != 0) 210 break; 211 if (filp->f_flags & O_NDELAY) { 212 spin_unlock_irqrestore(&emsgs_lock, flags); 213 return -EAGAIN; 214 } 215 nblocked_emsgs_readers++; 216 217 spin_unlock_irqrestore(&emsgs_lock, flags); 218 219 n = down_interruptible(&emsgs_sema); 220 221 spin_lock_irqsave(&emsgs_lock, flags); 222 223 nblocked_emsgs_readers--; 224 225 if (n) { 226 spin_unlock_irqrestore(&emsgs_lock, flags); 227 return -ERESTARTSYS; 228 } 229 } 230 if (em->len > cnt) { 231 spin_unlock_irqrestore(&emsgs_lock, flags); 232 return -EAGAIN; 233 } 234 mp = em->msg; 235 len = em->len; 236 em->msg = NULL; 237 em->flags &= ~EMFL_VALID; 238 239 emsgs_head_idx++; 240 emsgs_head_idx %= ARRAY_SIZE(emsgs); 241 242 spin_unlock_irqrestore(&emsgs_lock, flags); 243 244 n = copy_to_user(buf, mp, len); 245 kfree(mp); 246 return n == 0 ? len : -EFAULT; 247 } 248 249 static const struct file_operations aoe_fops = { 250 .write = aoechr_write, 251 .read = aoechr_read, 252 .open = aoechr_open, 253 .release = aoechr_rel, 254 .owner = THIS_MODULE, 255 }; 256 257 int __init 258 aoechr_init(void) 259 { 260 int n, i; 261 262 n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops); 263 if (n < 0) { 264 printk(KERN_ERR "aoe: can't register char device\n"); 265 return n; 266 } 267 sema_init(&emsgs_sema, 0); 268 spin_lock_init(&emsgs_lock); 269 aoe_class = class_create(THIS_MODULE, "aoe"); 270 if (IS_ERR(aoe_class)) { 271 unregister_chrdev(AOE_MAJOR, "aoechr"); 272 return PTR_ERR(aoe_class); 273 } 274 for (i = 0; i < ARRAY_SIZE(chardevs); ++i) 275 device_create(aoe_class, NULL, 276 MKDEV(AOE_MAJOR, chardevs[i].minor), chardevs[i].name); 277 278 return 0; 279 } 280 281 void 282 aoechr_exit(void) 283 { 284 int i; 285 286 for (i = 0; i < ARRAY_SIZE(chardevs); ++i) 287 device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor)); 288 class_destroy(aoe_class); 289 unregister_chrdev(AOE_MAJOR, "aoechr"); 290 } 291 292