android_kernel_samsung_msm8976/fs/filesystems.c
Tim Schmielau cd354f1ae7 [PATCH] remove many unneeded #includes of sched.h
After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there.  Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.

To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.

Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm.  I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).

Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-14 08:09:54 -08:00

234 lines
5.2 KiB
C

/*
* linux/fs/filesystems.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* table of configured filesystems
*/
#include <linux/syscalls.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/kmod.h>
#include <linux/init.h>
#include <linux/module.h>
#include <asm/uaccess.h>
/*
* Handling of filesystem drivers list.
* Rules:
* Inclusion to/removals from/scanning of list are protected by spinlock.
* During the unload module must call unregister_filesystem().
* We can access the fields of list element if:
* 1) spinlock is held or
* 2) we hold the reference to the module.
* The latter can be guaranteed by call of try_module_get(); if it
* returned 0 we must skip the element, otherwise we got the reference.
* Once the reference is obtained we can drop the spinlock.
*/
static struct file_system_type *file_systems;
static DEFINE_RWLOCK(file_systems_lock);
/* WARNING: This can be used only if we _already_ own a reference */
void get_filesystem(struct file_system_type *fs)
{
__module_get(fs->owner);
}
void put_filesystem(struct file_system_type *fs)
{
module_put(fs->owner);
}
static struct file_system_type **find_filesystem(const char *name)
{
struct file_system_type **p;
for (p=&file_systems; *p; p=&(*p)->next)
if (strcmp((*p)->name,name) == 0)
break;
return p;
}
/**
* register_filesystem - register a new filesystem
* @fs: the file system structure
*
* Adds the file system passed to the list of file systems the kernel
* is aware of for mount and other syscalls. Returns 0 on success,
* or a negative errno code on an error.
*
* The &struct file_system_type that is passed is linked into the kernel
* structures and must not be freed until the file system has been
* unregistered.
*/
int register_filesystem(struct file_system_type * fs)
{
int res = 0;
struct file_system_type ** p;
if (fs->next)
return -EBUSY;
INIT_LIST_HEAD(&fs->fs_supers);
write_lock(&file_systems_lock);
p = find_filesystem(fs->name);
if (*p)
res = -EBUSY;
else
*p = fs;
write_unlock(&file_systems_lock);
return res;
}
EXPORT_SYMBOL(register_filesystem);
/**
* unregister_filesystem - unregister a file system
* @fs: filesystem to unregister
*
* Remove a file system that was previously successfully registered
* with the kernel. An error is returned if the file system is not found.
* Zero is returned on a success.
*
* Once this function has returned the &struct file_system_type structure
* may be freed or reused.
*/
int unregister_filesystem(struct file_system_type * fs)
{
struct file_system_type ** tmp;
write_lock(&file_systems_lock);
tmp = &file_systems;
while (*tmp) {
if (fs == *tmp) {
*tmp = fs->next;
fs->next = NULL;
write_unlock(&file_systems_lock);
return 0;
}
tmp = &(*tmp)->next;
}
write_unlock(&file_systems_lock);
return -EINVAL;
}
EXPORT_SYMBOL(unregister_filesystem);
static int fs_index(const char __user * __name)
{
struct file_system_type * tmp;
char * name;
int err, index;
name = getname(__name);
err = PTR_ERR(name);
if (IS_ERR(name))
return err;
err = -EINVAL;
read_lock(&file_systems_lock);
for (tmp=file_systems, index=0 ; tmp ; tmp=tmp->next, index++) {
if (strcmp(tmp->name,name) == 0) {
err = index;
break;
}
}
read_unlock(&file_systems_lock);
putname(name);
return err;
}
static int fs_name(unsigned int index, char __user * buf)
{
struct file_system_type * tmp;
int len, res;
read_lock(&file_systems_lock);
for (tmp = file_systems; tmp; tmp = tmp->next, index--)
if (index <= 0 && try_module_get(tmp->owner))
break;
read_unlock(&file_systems_lock);
if (!tmp)
return -EINVAL;
/* OK, we got the reference, so we can safely block */
len = strlen(tmp->name) + 1;
res = copy_to_user(buf, tmp->name, len) ? -EFAULT : 0;
put_filesystem(tmp);
return res;
}
static int fs_maxindex(void)
{
struct file_system_type * tmp;
int index;
read_lock(&file_systems_lock);
for (tmp = file_systems, index = 0 ; tmp ; tmp = tmp->next, index++)
;
read_unlock(&file_systems_lock);
return index;
}
/*
* Whee.. Weird sysv syscall.
*/
asmlinkage long sys_sysfs(int option, unsigned long arg1, unsigned long arg2)
{
int retval = -EINVAL;
switch (option) {
case 1:
retval = fs_index((const char __user *) arg1);
break;
case 2:
retval = fs_name(arg1, (char __user *) arg2);
break;
case 3:
retval = fs_maxindex();
break;
}
return retval;
}
int get_filesystem_list(char * buf)
{
int len = 0;
struct file_system_type * tmp;
read_lock(&file_systems_lock);
tmp = file_systems;
while (tmp && len < PAGE_SIZE - 80) {
len += sprintf(buf+len, "%s\t%s\n",
(tmp->fs_flags & FS_REQUIRES_DEV) ? "" : "nodev",
tmp->name);
tmp = tmp->next;
}
read_unlock(&file_systems_lock);
return len;
}
struct file_system_type *get_fs_type(const char *name)
{
struct file_system_type *fs;
read_lock(&file_systems_lock);
fs = *(find_filesystem(name));
if (fs && !try_module_get(fs->owner))
fs = NULL;
read_unlock(&file_systems_lock);
if (!fs && (request_module("%s", name) == 0)) {
read_lock(&file_systems_lock);
fs = *(find_filesystem(name));
if (fs && !try_module_get(fs->owner))
fs = NULL;
read_unlock(&file_systems_lock);
}
return fs;
}
EXPORT_SYMBOL(get_fs_type);