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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 | /* * linux/fs/devices.c * * (C) 1993 Matthias Urlichs -- collected common code and tables. * * Copyright (C) 1991, 1992 Linus Torvalds * * Added kerneld support: Jacques Gelinas and Bjorn Ekwall * (changed to kmod) */ #include <linux/config.h> #include <linux/fs.h> #include <linux/major.h> #include <linux/string.h> #include <linux/sched.h> #include <linux/stat.h> #include <linux/fcntl.h> #include <linux/errno.h> #ifdef CONFIG_KMOD #include <linux/kmod.h> #include <linux/tty.h> /* serial module kmod load support */ struct tty_driver *get_tty_driver(kdev_t device); #define isa_tty_dev(ma) (ma == TTY_MAJOR || ma == TTYAUX_MAJOR) #define need_serial(ma,mi) (get_tty_driver(MKDEV(ma,mi)) == NULL) #endif struct device_struct { const char * name; struct file_operations * fops; }; static struct device_struct chrdevs[MAX_CHRDEV] = { { NULL, NULL }, }; static struct device_struct blkdevs[MAX_BLKDEV] = { { NULL, NULL }, }; int get_device_list(char * page) { int i; int len; len = sprintf(page, "Character devices:\n"); for (i = 0; i < MAX_CHRDEV ; i++) { if (chrdevs[i].fops) { len += sprintf(page+len, "%2d %s\n", i, chrdevs[i].name); } } len += sprintf(page+len, "\nBlock devices:\n"); for (i = 0; i < MAX_BLKDEV ; i++) { if (blkdevs[i].fops) { len += sprintf(page+len, "%2d %s\n", i, blkdevs[i].name); } } return len; } /* Return the function table of a device. Load the driver if needed. */ static struct file_operations * get_fops( unsigned int major, unsigned int minor, unsigned int maxdev, const char *mangle, /* String to use to build the module name */ struct device_struct tb[]) { struct file_operations *ret = NULL; if (major < maxdev){ #ifdef CONFIG_KMOD /* * I do get request for device 0. I have no idea why. It happen * at shutdown time for one. Without the following test, the * kernel will happily trigger a request_module() which will * trigger kmod and modprobe for nothing (since there * is no device with major number == 0. And furthermore * it locks the reboot process :-( * * Jacques Gelinas (jacques@solucorp.qc.ca) * * A. Haritsis <ah@doc.ic.ac.uk>: fix for serial module * though we need the minor here to check if serial dev, * we pass only the normal major char dev to kmod * as there is no other loadable dev on these majors */ if ((isa_tty_dev(major) && need_serial(major,minor)) || (major != 0 && !tb[major].fops)) { char name[20]; sprintf(name, mangle, major); request_module(name); } #endif ret = tb[major].fops; } return ret; } /* Return the function table of a device. Load the driver if needed. */ struct file_operations * get_blkfops(unsigned int major) { return get_fops (major,0,MAX_BLKDEV,"block-major-%d",blkdevs); } struct file_operations * get_chrfops(unsigned int major, unsigned int minor) { return get_fops (major,minor,MAX_CHRDEV,"char-major-%d",chrdevs); } int register_chrdev(unsigned int major, const char * name, struct file_operations *fops) { if (major == 0) { for (major = MAX_CHRDEV-1; major > 0; major--) { if (chrdevs[major].fops == NULL) { chrdevs[major].name = name; chrdevs[major].fops = fops; return major; } } return -EBUSY; } if (major >= MAX_CHRDEV) return -EINVAL; if (chrdevs[major].fops && chrdevs[major].fops != fops) return -EBUSY; chrdevs[major].name = name; chrdevs[major].fops = fops; return 0; } int register_blkdev(unsigned int major, const char * name, struct file_operations *fops) { if (major == 0) { for (major = MAX_BLKDEV-1; major > 0; major--) { if (blkdevs[major].fops == NULL) { blkdevs[major].name = name; blkdevs[major].fops = fops; return major; } } return -EBUSY; } if (major >= MAX_BLKDEV) return -EINVAL; if (blkdevs[major].fops && blkdevs[major].fops != fops) return -EBUSY; blkdevs[major].name = name; blkdevs[major].fops = fops; return 0; } int unregister_chrdev(unsigned int major, const char * name) { if (major >= MAX_CHRDEV) return -EINVAL; if (!chrdevs[major].fops) return -EINVAL; if (strcmp(chrdevs[major].name, name)) return -EINVAL; chrdevs[major].name = NULL; chrdevs[major].fops = NULL; return 0; } int unregister_blkdev(unsigned int major, const char * name) { if (major >= MAX_BLKDEV) return -EINVAL; if (!blkdevs[major].fops) return -EINVAL; if (strcmp(blkdevs[major].name, name)) return -EINVAL; blkdevs[major].name = NULL; blkdevs[major].fops = NULL; return 0; } /* * This routine checks whether a removable media has been changed, * and invalidates all buffer-cache-entries in that case. This * is a relatively slow routine, so we have to try to minimize using * it. Thus it is called only upon a 'mount' or 'open'. This * is the best way of combining speed and utility, I think. * People changing diskettes in the middle of an operation deserve * to loose :-) */ int check_disk_change(kdev_t dev) { int i; struct file_operations * fops; struct super_block * sb; i = MAJOR(dev); if (i >= MAX_BLKDEV || (fops = blkdevs[i].fops) == NULL) return 0; if (fops->check_media_change == NULL) return 0; if (!fops->check_media_change(dev)) return 0; printk(KERN_DEBUG "VFS: Disk change detected on device %s\n", kdevname(dev)); sb = get_super(dev); if (sb && invalidate_inodes(sb)) printk("VFS: busy inodes on changed media..\n"); invalidate_buffers(dev); if (fops->revalidate) fops->revalidate(dev); return 1; } /* * Called every time a block special file is opened */ int blkdev_open(struct inode * inode, struct file * filp) { int ret = -ENODEV; filp->f_op = get_blkfops(MAJOR(inode->i_rdev)); if (filp->f_op != NULL){ ret = 0; if (filp->f_op->open != NULL) ret = filp->f_op->open(inode,filp); } return ret; } int blkdev_release(struct inode * inode) { struct file_operations *fops = get_blkfops(MAJOR(inode->i_rdev)); if (fops && fops->release) return fops->release(inode,NULL); return 0; } /* * Dummy default file-operations: the only thing this does * is contain the open that then fills in the correct operations * depending on the special file... */ struct file_operations def_blk_fops = { NULL, /* lseek */ NULL, /* read */ NULL, /* write */ NULL, /* readdir */ NULL, /* poll */ NULL, /* ioctl */ NULL, /* mmap */ blkdev_open, /* open */ NULL, /* release */ }; struct inode_operations blkdev_inode_operations = { &def_blk_fops, /* default file operations */ NULL, /* create */ NULL, /* lookup */ NULL, /* link */ NULL, /* unlink */ NULL, /* symlink */ NULL, /* mkdir */ NULL, /* rmdir */ NULL, /* mknod */ NULL, /* rename */ NULL, /* readlink */ NULL, /* readpage */ NULL, /* writepage */ NULL, /* bmap */ NULL, /* truncate */ NULL /* permission */ }; /* * Called every time a character special file is opened */ int chrdev_open(struct inode * inode, struct file * filp) { int ret = -ENODEV; filp->f_op = get_chrfops(MAJOR(inode->i_rdev), MINOR(inode->i_rdev)); if (filp->f_op != NULL){ ret = 0; if (filp->f_op->open != NULL) ret = filp->f_op->open(inode,filp); } return ret; } /* * Dummy default file-operations: the only thing this does * is contain the open that then fills in the correct operations * depending on the special file... */ struct file_operations def_chr_fops = { NULL, /* lseek */ NULL, /* read */ NULL, /* write */ NULL, /* readdir */ NULL, /* poll */ NULL, /* ioctl */ NULL, /* mmap */ chrdev_open, /* open */ NULL, /* release */ }; struct inode_operations chrdev_inode_operations = { &def_chr_fops, /* default file operations */ NULL, /* create */ NULL, /* lookup */ NULL, /* link */ NULL, /* unlink */ NULL, /* symlink */ NULL, /* mkdir */ NULL, /* rmdir */ NULL, /* mknod */ NULL, /* rename */ NULL, /* readlink */ NULL, /* readpage */ NULL, /* writepage */ NULL, /* bmap */ NULL, /* truncate */ NULL /* permission */ }; /* * Print device name (in decimal, hexadecimal or symbolic) - * at present hexadecimal only. * Note: returns pointer to static data! */ char * kdevname(kdev_t dev) { static char buffer[32]; sprintf(buffer, "%02x:%02x", MAJOR(dev), MINOR(dev)); return buffer; } |