1 /* 2 * mount.c - operations for initializing and mounting sysfs. 3 */ 4 5 #define DEBUG 6 7 #include <linux/fs.h> 8 #include <linux/mount.h> 9 #include <linux/pagemap.h> 10 #include <linux/init.h> 11 12 #include "sysfs.h" 13 14 /* Random magic number */ 15 #define SYSFS_MAGIC 0x62656572 16 17 struct vfsmount *sysfs_mount; 18 struct super_block * sysfs_sb = NULL; 19 kmem_cache_t *sysfs_dir_cachep; 20 21 static struct super_operations sysfs_ops = { 22 .statfs = simple_statfs, 23 .drop_inode = generic_delete_inode, 24 }; 25 26 static struct sysfs_dirent sysfs_root = { 27 .s_sibling = LIST_HEAD_INIT(sysfs_root.s_sibling), 28 .s_children = LIST_HEAD_INIT(sysfs_root.s_children), 29 .s_element = NULL, 30 .s_type = SYSFS_ROOT, 31 .s_iattr = NULL, 32 }; 33 34 static int sysfs_fill_super(struct super_block *sb, void *data, int silent) 35 { 36 struct inode *inode; 37 struct dentry *root; 38 39 sb->s_blocksize = PAGE_CACHE_SIZE; 40 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 41 sb->s_magic = SYSFS_MAGIC; 42 sb->s_op = &sysfs_ops; 43 sb->s_time_gran = 1; 44 sysfs_sb = sb; 45 46 inode = sysfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, 47 &sysfs_root); 48 if (inode) { 49 inode->i_op = &sysfs_dir_inode_operations; 50 inode->i_fop = &sysfs_dir_operations; 51 /* directory inodes start off with i_nlink == 2 (for "." entry) */ 52 inode->i_nlink++; 53 } else { 54 pr_debug("sysfs: could not get root inode\n"); 55 return -ENOMEM; 56 } 57 58 root = d_alloc_root(inode); 59 if (!root) { 60 pr_debug("%s: could not get root dentry!\n",__FUNCTION__); 61 iput(inode); 62 return -ENOMEM; 63 } 64 root->d_fsdata = &sysfs_root; 65 sb->s_root = root; 66 return 0; 67 } 68 69 static struct super_block *sysfs_get_sb(struct file_system_type *fs_type, 70 int flags, const char *dev_name, void *data) 71 { 72 return get_sb_single(fs_type, flags, data, sysfs_fill_super); 73 } 74 75 static struct file_system_type sysfs_fs_type = { 76 .name = "sysfs", 77 .get_sb = sysfs_get_sb, 78 .kill_sb = kill_litter_super, 79 }; 80 81 int __init sysfs_init(void) 82 { 83 int err = -ENOMEM; 84 85 sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache", 86 sizeof(struct sysfs_dirent), 87 0, 0, NULL, NULL); 88 if (!sysfs_dir_cachep) 89 goto out; 90 91 err = register_filesystem(&sysfs_fs_type); 92 if (!err) { 93 sysfs_mount = kern_mount(&sysfs_fs_type); 94 if (IS_ERR(sysfs_mount)) { 95 printk(KERN_ERR "sysfs: could not mount!\n"); 96 err = PTR_ERR(sysfs_mount); 97 sysfs_mount = NULL; 98 unregister_filesystem(&sysfs_fs_type); 99 goto out_err; 100 } 101 } else 102 goto out_err; 103 out: 104 return err; 105 out_err: 106 kmem_cache_destroy(sysfs_dir_cachep); 107 sysfs_dir_cachep = NULL; 108 goto out; 109 } 110