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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /mm/tiny-shmem.c | |
download | blackbird-op-linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz blackbird-op-linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'mm/tiny-shmem.c')
-rw-r--r-- | mm/tiny-shmem.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/mm/tiny-shmem.c b/mm/tiny-shmem.c new file mode 100644 index 000000000000..c13a2161bca2 --- /dev/null +++ b/mm/tiny-shmem.c @@ -0,0 +1,122 @@ +/* + * tiny-shmem.c: simple shmemfs and tmpfs using ramfs code + * + * Matt Mackall <mpm@selenic.com> January, 2004 + * derived from mm/shmem.c and fs/ramfs/inode.c + * + * This is intended for small system where the benefits of the full + * shmem code (swap-backed and resource-limited) are outweighed by + * their complexity. On systems without swap this code should be + * effectively equivalent, but much lighter weight. + */ + +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/devfs_fs_kernel.h> +#include <linux/vfs.h> +#include <linux/mount.h> +#include <linux/file.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/swap.h> +#include <linux/ramfs.h> + +static struct file_system_type tmpfs_fs_type = { + .name = "tmpfs", + .get_sb = ramfs_get_sb, + .kill_sb = kill_litter_super, +}; + +static struct vfsmount *shm_mnt; + +static int __init init_tmpfs(void) +{ + register_filesystem(&tmpfs_fs_type); +#ifdef CONFIG_TMPFS + devfs_mk_dir("shm"); +#endif + shm_mnt = kern_mount(&tmpfs_fs_type); + return 0; +} +module_init(init_tmpfs) + +/* + * shmem_file_setup - get an unlinked file living in tmpfs + * + * @name: name for dentry (to be seen in /proc/<pid>/maps + * @size: size to be set for the file + * + */ +struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) +{ + int error; + struct file *file; + struct inode *inode; + struct dentry *dentry, *root; + struct qstr this; + + if (IS_ERR(shm_mnt)) + return (void *)shm_mnt; + + error = -ENOMEM; + this.name = name; + this.len = strlen(name); + this.hash = 0; /* will go */ + root = shm_mnt->mnt_root; + dentry = d_alloc(root, &this); + if (!dentry) + goto put_memory; + + error = -ENFILE; + file = get_empty_filp(); + if (!file) + goto put_dentry; + + error = -ENOSPC; + inode = ramfs_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); + if (!inode) + goto close_file; + + d_instantiate(dentry, inode); + inode->i_size = size; + inode->i_nlink = 0; /* It is unlinked */ + file->f_vfsmnt = mntget(shm_mnt); + file->f_dentry = dentry; + file->f_mapping = inode->i_mapping; + file->f_op = &ramfs_file_operations; + file->f_mode = FMODE_WRITE | FMODE_READ; + return file; + +close_file: + put_filp(file); +put_dentry: + dput(dentry); +put_memory: + return ERR_PTR(error); +} + +/* + * shmem_zero_setup - setup a shared anonymous mapping + * + * @vma: the vma to be mmapped is prepared by do_mmap_pgoff + */ +int shmem_zero_setup(struct vm_area_struct *vma) +{ + struct file *file; + loff_t size = vma->vm_end - vma->vm_start; + + file = shmem_file_setup("dev/zero", size, vma->vm_flags); + if (IS_ERR(file)) + return PTR_ERR(file); + + if (vma->vm_file) + fput(vma->vm_file); + vma->vm_file = file; + vma->vm_ops = &generic_file_vm_ops; + return 0; +} + +int shmem_unuse(swp_entry_t entry, struct page *page) +{ + return 0; +} |