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 } 244 245