1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/fs.h> 3 #include <linux/init.h> 4 #include <linux/proc_fs.h> 5 #include <linux/seq_file.h> 6 #include <linux/blkdev.h> 7 #include "internal.h" 8 9 static int devinfo_show(struct seq_file *f, void *v) 10 { 11 int i = *(loff_t *) v; 12 13 if (i < CHRDEV_MAJOR_MAX) { 14 if (i == 0) 15 seq_puts(f, "Character devices:\n"); 16 chrdev_show(f, i); 17 } 18 #ifdef CONFIG_BLOCK 19 else { 20 i -= CHRDEV_MAJOR_MAX; 21 if (i == 0) 22 seq_puts(f, "\nBlock devices:\n"); 23 blkdev_show(f, i); 24 } 25 #endif 26 return 0; 27 } 28 29 static void *devinfo_start(struct seq_file *f, loff_t *pos) 30 { 31 if (*pos < (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX)) 32 return pos; 33 return NULL; 34 } 35 36 static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos) 37 { 38 (*pos)++; 39 if (*pos >= (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX)) 40 return NULL; 41 return pos; 42 } 43 44 static void devinfo_stop(struct seq_file *f, void *v) 45 { 46 /* Nothing to do */ 47 } 48 49 static const struct seq_operations devinfo_ops = { 50 .start = devinfo_start, 51 .next = devinfo_next, 52 .stop = devinfo_stop, 53 .show = devinfo_show 54 }; 55 56 static int __init proc_devices_init(void) 57 { 58 struct proc_dir_entry *pde; 59 60 pde = proc_create_seq("devices", 0, NULL, &devinfo_ops); 61 pde_make_permanent(pde); 62 return 0; 63 } 64 fs_initcall(proc_devices_init); 65