mac80211: integrate sta_notify_ps cmds into sta_notify
[linux-2.6] / mm / tiny-shmem.c
1 /*
2  * tiny-shmem.c: simple shmemfs and tmpfs using ramfs code
3  *
4  * Matt Mackall <mpm@selenic.com> January, 2004
5  * derived from mm/shmem.c and fs/ramfs/inode.c
6  *
7  * This is intended for small system where the benefits of the full
8  * shmem code (swap-backed and resource-limited) are outweighed by
9  * their complexity. On systems without swap this code should be
10  * effectively equivalent, but much lighter weight.
11  */
12
13 #include <linux/fs.h>
14 #include <linux/init.h>
15 #include <linux/vfs.h>
16 #include <linux/mount.h>
17 #include <linux/file.h>
18 #include <linux/mm.h>
19 #include <linux/module.h>
20 #include <linux/swap.h>
21 #include <linux/ramfs.h>
22
23 static struct file_system_type tmpfs_fs_type = {
24         .name           = "tmpfs",
25         .get_sb         = ramfs_get_sb,
26         .kill_sb        = kill_litter_super,
27 };
28
29 static struct vfsmount *shm_mnt;
30
31 static int __init init_tmpfs(void)
32 {
33         BUG_ON(register_filesystem(&tmpfs_fs_type) != 0);
34
35         shm_mnt = kern_mount(&tmpfs_fs_type);
36         BUG_ON(IS_ERR(shm_mnt));
37
38         return 0;
39 }
40 module_init(init_tmpfs)
41
42 /**
43  * shmem_file_setup - get an unlinked file living in tmpfs
44  * @name: name for dentry (to be seen in /proc/<pid>/maps
45  * @size: size to be set for the file
46  * @flags: vm_flags
47  */
48 struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
49 {
50         int error;
51         struct file *file;
52         struct inode *inode;
53         struct dentry *dentry, *root;
54         struct qstr this;
55
56         if (IS_ERR(shm_mnt))
57                 return (void *)shm_mnt;
58
59         error = -ENOMEM;
60         this.name = name;
61         this.len = strlen(name);
62         this.hash = 0; /* will go */
63         root = shm_mnt->mnt_root;
64         dentry = d_alloc(root, &this);
65         if (!dentry)
66                 goto put_memory;
67
68         error = -ENFILE;
69         file = get_empty_filp();
70         if (!file)
71                 goto put_dentry;
72
73         error = -ENOSPC;
74         inode = ramfs_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
75         if (!inode)
76                 goto close_file;
77
78         d_instantiate(dentry, inode);
79         inode->i_size = size;
80         inode->i_nlink = 0;     /* It is unlinked */
81         init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
82                         &ramfs_file_operations);
83
84 #ifndef CONFIG_MMU
85         error = ramfs_nommu_expand_for_mapping(inode, size);
86         if (error)
87                 goto close_file;
88 #endif
89         return file;
90
91 close_file:
92         put_filp(file);
93 put_dentry:
94         dput(dentry);
95 put_memory:
96         return ERR_PTR(error);
97 }
98 EXPORT_SYMBOL_GPL(shmem_file_setup);
99
100 /**
101  * shmem_zero_setup - setup a shared anonymous mapping
102  * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
103  */
104 int shmem_zero_setup(struct vm_area_struct *vma)
105 {
106         struct file *file;
107         loff_t size = vma->vm_end - vma->vm_start;
108
109         file = shmem_file_setup("dev/zero", size, vma->vm_flags);
110         if (IS_ERR(file))
111                 return PTR_ERR(file);
112
113         if (vma->vm_file)
114                 fput(vma->vm_file);
115         vma->vm_file = file;
116         vma->vm_ops = &generic_file_vm_ops;
117         return 0;
118 }
119
120 int shmem_unuse(swp_entry_t entry, struct page *page)
121 {
122         return 0;
123 }
124
125 #ifndef CONFIG_MMU
126 unsigned long shmem_get_unmapped_area(struct file *file,
127                                       unsigned long addr,
128                                       unsigned long len,
129                                       unsigned long pgoff,
130                                       unsigned long flags)
131 {
132         return ramfs_nommu_get_unmapped_area(file, addr, len, pgoff, flags);
133 }
134 #endif