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/completion.h> 10 #include <linux/delay.h> 11 #include <linux/slab.h> 12 #include <linux/mutex.h> 13 #include <linux/skbuff.h> 14 #include <linux/export.h> 15 #include "aoe.h" 16 17 enum { 18 //MINOR_STAT = 1, (moved to sysfs) 19 MINOR_ERR = 2, 20 MINOR_DISCOVER, 21 MINOR_INTERFACES, 22 MINOR_REVALIDATE, 23 MINOR_FLUSH, 24 MSGSZ = 2048, 25 NMSG = 100, /* message backlog to retain */ 26 }; 27 28 struct aoe_chardev { 29 ulong minor; 30 char name[32]; 31 }; 32 33 enum { EMFL_VALID = 1 }; 34 35 struct ErrMsg { 36 short flags; 37 short len; 38 char *msg; 39 }; 40 41 static DEFINE_MUTEX(aoechr_mutex); 42 static struct ErrMsg emsgs[NMSG]; 43 static int emsgs_head_idx, emsgs_tail_idx; 44 static struct completion emsgs_comp; 45 static spinlock_t emsgs_lock; 46 static int nblocked_emsgs_readers; 47 static struct class *aoe_class; 48 static struct aoe_chardev chardevs[] = { 49 { MINOR_ERR, "err" }, 50 { MINOR_DISCOVER, "discover" }, 51 { MINOR_INTERFACES, "interfaces" }, 52 { MINOR_REVALIDATE, "revalidate" }, 53 { MINOR_FLUSH, "flush" }, 54 }; 55 56 static int 57 discover(void) 58 { 59 aoecmd_cfg(0xffff, 0xff); 60 return 0; 61 } 62 63 static int 64 interfaces(const char __user *str, size_t size) 65 { 66 if (set_aoe_iflist(str, size)) { 67 printk(KERN_ERR 68 "aoe: could not set interface list: too many interfaces\n"); 69 return -EINVAL; 70 } 71 return 0; 72 } 73 74 static int 75 revalidate(const char __user *str, size_t size) 76 { 77 int major, minor, n; 78 ulong flags; 79 struct aoedev *d; 80 struct sk_buff *skb; 81 char buf[16]; 82 83 if (size >= sizeof buf) 84 return -EINVAL; 85 buf[sizeof buf - 1] = '\0'; 86 if (copy_from_user(buf, str, size)) 87 return -EFAULT; 88 89 n = sscanf(buf, "e%d.%d", &major, &minor); 90 if (n != 2) { 91 pr_err("aoe: invalid device specification %s\n", buf); 92 return -EINVAL; 93 } 94 d = aoedev_by_aoeaddr(major, minor); 95 if (!d) 96 return -EINVAL; 97 spin_lock_irqsave(&d->lock, flags); 98 aoecmd_cleanslate(d); 99 loop: 100 skb = aoecmd_ata_id(d); 101 spin_unlock_irqrestore(&d->lock, flags); 102 /* try again if we are able to sleep a bit, 103 * otherwise give up this revalidation 104 */ 105 if (!skb && !msleep_interruptible(200)) { 106 spin_lock_irqsave(&d->lock, flags); 107 goto loop; 108 } 109 if (skb) { 110 struct sk_buff_head queue; 111 __skb_queue_head_init(&queue); 112 __skb_queue_tail(&queue, skb); 113 aoenet_xmit(&queue); 114 } 115 aoecmd_cfg(major, minor); 116 return 0; 117 } 118 119 void 120 aoechr_error(char *msg) 121 { 122 struct ErrMsg *em; 123 char *mp; 124 ulong flags, n; 125 126 n = strlen(msg); 127 128 spin_lock_irqsave(&emsgs_lock, flags); 129 130 em = emsgs + emsgs_tail_idx; 131 if ((em->flags & EMFL_VALID)) { 132 bail: spin_unlock_irqrestore(&emsgs_lock, flags); 133 return; 134 } 135 136 mp = kmalloc(n, GFP_ATOMIC); 137 if (mp == NULL) { 138 printk(KERN_ERR "aoe: allocation failure, len=%ld\n", n); 139 goto bail; 140 } 141 142 memcpy(mp, msg, n); 143 em->msg = mp; 144 em->flags |= EMFL_VALID; 145 em->len = n; 146 147 emsgs_tail_idx++; 148 emsgs_tail_idx %= ARRAY_SIZE(emsgs); 149 150 spin_unlock_irqrestore(&emsgs_lock, flags); 151 152 if (nblocked_emsgs_readers) 153 complete(&emsgs_comp); 154 } 155 156 static ssize_t 157 aoechr_write(struct file *filp, const char __user *buf, size_t cnt, loff_t *offp) 158 { 159 int ret = -EINVAL; 160 161 switch ((unsigned long) filp->private_data) { 162 default: 163 printk(KERN_INFO "aoe: can't write to that file.\n"); 164 break; 165 case MINOR_DISCOVER: 166 ret = discover(); 167 break; 168 case MINOR_INTERFACES: 169 ret = interfaces(buf, cnt); 170 break; 171 case MINOR_REVALIDATE: 172 ret = revalidate(buf, cnt); 173 break; 174 case MINOR_FLUSH: 175 ret = aoedev_flush(buf, cnt); 176 } 177 if (ret == 0) 178 ret = cnt; 179 return ret; 180 } 181 182 static int 183 aoechr_open(struct inode *inode, struct file *filp) 184 { 185 int n, i; 186 187 mutex_lock(&aoechr_mutex); 188 n = iminor(inode); 189 filp->private_data = (void *) (unsigned long) n; 190 191 for (i = 0; i < ARRAY_SIZE(chardevs); ++i) 192 if (chardevs[i].minor == n) { 193 mutex_unlock(&aoechr_mutex); 194 return 0; 195 } 196 mutex_unlock(&aoechr_mutex); 197 return -EINVAL; 198 } 199 200 static int 201 aoechr_rel(struct inode *inode, struct file *filp) 202 { 203 return 0; 204 } 205 206 static ssize_t 207 aoechr_read(struct file *filp, char __user *buf, size_t cnt, loff_t *off) 208 { 209 unsigned long n; 210 char *mp; 211 struct ErrMsg *em; 212 ssize_t len; 213 ulong flags; 214 215 n = (unsigned long) filp->private_data; 216 if (n != MINOR_ERR) 217 return -EFAULT; 218 219 spin_lock_irqsave(&emsgs_lock, flags); 220 221 for (;;) { 222 em = emsgs + emsgs_head_idx; 223 if ((em->flags & EMFL_VALID) != 0) 224 break; 225 if (filp->f_flags & O_NDELAY) { 226 spin_unlock_irqrestore(&emsgs_lock, flags); 227 return -EAGAIN; 228 } 229 nblocked_emsgs_readers++; 230 231 spin_unlock_irqrestore(&emsgs_lock, flags); 232 233 n = wait_for_completion_interruptible(&emsgs_comp); 234 235 spin_lock_irqsave(&emsgs_lock, flags); 236 237 nblocked_emsgs_readers--; 238 239 if (n) { 240 spin_unlock_irqrestore(&emsgs_lock, flags); 241 return -ERESTARTSYS; 242 } 243 } 244 if (em->len > cnt) { 245 spin_unlock_irqrestore(&emsgs_lock, flags); 246 return -EAGAIN; 247 } 248 mp = em->msg; 249 len = em->len; 250 em->msg = NULL; 251 em->flags &= ~EMFL_VALID; 252 253 emsgs_head_idx++; 254 emsgs_head_idx %= ARRAY_SIZE(emsgs); 255 256 spin_unlock_irqrestore(&emsgs_lock, flags); 257 258 n = copy_to_user(buf, mp, len); 259 kfree(mp); 260 return n == 0 ? len : -EFAULT; 261 } 262 263 static const struct file_operations aoe_fops = { 264 .write = aoechr_write, 265 .read = aoechr_read, 266 .open = aoechr_open, 267 .release = aoechr_rel, 268 .owner = THIS_MODULE, 269 .llseek = noop_llseek, 270 }; 271 272 static char *aoe_devnode(struct device *dev, umode_t *mode) 273 { 274 return kasprintf(GFP_KERNEL, "etherd/%s", dev_name(dev)); 275 } 276 277 int __init 278 aoechr_init(void) 279 { 280 int n, i; 281 282 n = register_chrdev(AOE_MAJOR, "aoechr", &aoe_fops); 283 if (n < 0) { 284 printk(KERN_ERR "aoe: can't register char device\n"); 285 return n; 286 } 287 init_completion(&emsgs_comp); 288 spin_lock_init(&emsgs_lock); 289 aoe_class = class_create(THIS_MODULE, "aoe"); 290 if (IS_ERR(aoe_class)) { 291 unregister_chrdev(AOE_MAJOR, "aoechr"); 292 return PTR_ERR(aoe_class); 293 } 294 aoe_class->devnode = aoe_devnode; 295 296 for (i = 0; i < ARRAY_SIZE(chardevs); ++i) 297 device_create(aoe_class, NULL, 298 MKDEV(AOE_MAJOR, chardevs[i].minor), NULL, 299 chardevs[i].name); 300 301 return 0; 302 } 303 304 void 305 aoechr_exit(void) 306 { 307 int i; 308 309 for (i = 0; i < ARRAY_SIZE(chardevs); ++i) 310 device_destroy(aoe_class, MKDEV(AOE_MAJOR, chardevs[i].minor)); 311 class_destroy(aoe_class); 312 unregister_chrdev(AOE_MAJOR, "aoechr"); 313 } 314 315