Commit 853ac43a authored by Matt Mackall's avatar Matt Mackall Committed by Linus Torvalds
Browse files

shmem: unify regular and tiny shmem 



tiny-shmem shares most of its 130 lines of code with shmem and tends to
break when particular bits of shmem get modified.  Unifying saves code and
makes keeping these two in sync much easier.

before:
  14367	    392	     24	  14783	   39bf	mm/shmem.o
    396      72       8     476	    1dc	mm/tiny-shmem.o

after:
  14367	    392	     24	  14783	   39bf	mm/shmem.o
    412	     72       8     492	    1ec	mm/shmem.o tiny

Signed-off-by: default avatarMatt Mackall <mpm@selenic.com>
Acked-by: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 69e99309

init/Kconfig

+0 −4
Original line number Diff line number Diff line
@@ -838,10 +838,6 @@ config RT_MUTEXES 
	boolean

	select PLIST



config TINY_SHMEM

	default !SHMEM

	bool



config BASE_SMALL

	int

	default 0 if BASE_FULL

mm/Makefile

+1 −3
Original line number Diff line number Diff line
@@ -9,7 +9,7 @@ mmu-$(CONFIG_MMU) := fremap.o highmem.o madvise.o memory.o mincore.o \ 


obj-y			:= bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \

			   maccess.o page_alloc.o page-writeback.o pdflush.o \

			   readahead.o swap.o truncate.o vmscan.o \

			   readahead.o swap.o truncate.o vmscan.o shmem.o \

			   prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \

			   page_isolation.o mm_init.o $(mmu-y)
@@ -21,9 +21,7 @@ obj-$(CONFIG_HUGETLBFS) += hugetlb.o 
obj-$(CONFIG_NUMA) 	+= mempolicy.o

obj-$(CONFIG_SPARSEMEM)	+= sparse.o

obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o

obj-$(CONFIG_SHMEM) += shmem.o

obj-$(CONFIG_TMPFS_POSIX_ACL) += shmem_acl.o

obj-$(CONFIG_TINY_SHMEM) += tiny-shmem.o

obj-$(CONFIG_SLOB) += slob.o

obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o

obj-$(CONFIG_SLAB) += slab.o

mm/shmem.c

+71 −10
Original line number Diff line number Diff line
@@ -14,31 +14,39 @@ 
 * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net>

 * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>

 *

 * tiny-shmem:

 * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com>

 *

 * This file is released under the GPL.

 */



#include <linux/fs.h>

#include <linux/init.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>



static struct vfsmount *shm_mnt;



#ifdef CONFIG_SHMEM

/*

 * This virtual memory filesystem is heavily based on the ramfs. It

 * extends ramfs by the ability to use swap and honor resource limits

 * which makes it a completely usable filesystem.

 */



#include <linux/module.h>

#include <linux/init.h>

#include <linux/fs.h>

#include <linux/xattr.h>

#include <linux/exportfs.h>

#include <linux/generic_acl.h>

#include <linux/mm.h>

#include <linux/mman.h>

#include <linux/file.h>

#include <linux/swap.h>

#include <linux/pagemap.h>

#include <linux/string.h>

#include <linux/slab.h>

#include <linux/backing-dev.h>

#include <linux/shmem_fs.h>

#include <linux/mount.h>

#include <linux/writeback.h>

#include <linux/vfs.h>

#include <linux/blkdev.h>
@@ -2485,7 +2493,6 @@ static struct file_system_type tmpfs_fs_type = { 
	.get_sb		= shmem_get_sb,

	.kill_sb	= kill_litter_super,

};

static struct vfsmount *shm_mnt;



static int __init init_tmpfs(void)

{
@@ -2524,7 +2531,51 @@ out4: 
	shm_mnt = ERR_PTR(error);

	return error;

}

module_init(init_tmpfs)



#else /* !CONFIG_SHMEM */



/*

 * tiny-shmem: simple shmemfs and tmpfs using ramfs code

 *

 * 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/ramfs.h>



static struct file_system_type tmpfs_fs_type = {

	.name		= "tmpfs",

	.get_sb		= ramfs_get_sb,

	.kill_sb	= kill_litter_super,

};



static int __init init_tmpfs(void)

{

	BUG_ON(register_filesystem(&tmpfs_fs_type) != 0);



	shm_mnt = kern_mount(&tmpfs_fs_type);

	BUG_ON(IS_ERR(shm_mnt));



	return 0;

}



int shmem_unuse(swp_entry_t entry, struct page *page)

{

	return 0;

}



#define shmem_file_operations ramfs_file_operations

#define shmem_vm_ops generic_file_vm_ops

#define shmem_get_inode ramfs_get_inode

#define shmem_acct_size(a, b) 0

#define shmem_unacct_size(a, b) do {} while (0)

#define SHMEM_MAX_BYTES LLONG_MAX



#endif /* CONFIG_SHMEM */



/* common code */



/**

 * shmem_file_setup - get an unlinked file living in tmpfs
@@ -2568,12 +2619,20 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) 
	if (!inode)

		goto close_file;



#ifdef CONFIG_SHMEM

	SHMEM_I(inode)->flags = flags & VM_ACCOUNT;

#endif

	d_instantiate(dentry, inode);

	inode->i_size = size;

	inode->i_nlink = 0;	/* It is unlinked */

	init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,

		  &shmem_file_operations);



#ifndef CONFIG_MMU

	error = ramfs_nommu_expand_for_mapping(inode, size);

	if (error)

		goto close_file;

#endif

	return file;



close_file:
@@ -2605,3 +2664,5 @@ int shmem_zero_setup(struct vm_area_struct *vma) 
	vma->vm_ops = &shmem_vm_ops;

	return 0;

}



module_init(init_tmpfs)

mm/tiny-shmem.c

deleted100644 → 0
+0 −134
Original line number Diff line number Diff line 
/*

 * 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/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)

{

	BUG_ON(register_filesystem(&tmpfs_fs_type) != 0);



	shm_mnt = kern_mount(&tmpfs_fs_type);

	BUG_ON(IS_ERR(shm_mnt));



	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

 * @flags: vm_flags

 */

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 */

	init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,

			&ramfs_file_operations);



#ifndef CONFIG_MMU

	error = ramfs_nommu_expand_for_mapping(inode, size);

	if (error)

		goto close_file;

#endif

	return file;



close_file:

	put_filp(file);

put_dentry:

	dput(dentry);

put_memory:

	return ERR_PTR(error);

}

EXPORT_SYMBOL_GPL(shmem_file_setup);



/**

 * 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;

}



#ifndef CONFIG_MMU

unsigned long shmem_get_unmapped_area(struct file *file,

				      unsigned long addr,

				      unsigned long len,

				      unsigned long pgoff,

				      unsigned long flags)

{

	return ramfs_nommu_get_unmapped_area(file, addr, len, pgoff, flags);

}

#endif

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