xattr: extract simple_xattr code from tmpfs

Extract in-memory xattr APIs from tmpfs. Will be used by cgroup.

$ size vmlinux.o
   text    data     bss     dec     hex filename
4658782  880729 5195032 10734543         a3cbcf vmlinux.o
$ size vmlinux.o
   text    data     bss     dec     hex filename
4658957  880729 5195032 10734718         a3cc7e vmlinux.o

v7:
- checkpatch warnings fixed
- Implement the changes requested by Hugh Dickins:
	- make simple_xattrs_init and simple_xattrs_free inline
	- get rid of locking and list reinitialization in simple_xattrs_free,
	  they're not needed
v6:
- no changes
v5:
- no changes
v4:
- move simple_xattrs_free() to fs/xattr.c
v3:
- in kmem_xattrs_free(), reinitialize the list
- use simple_xattr_* prefix
- introduce simple_xattr_add() to prevent direct list usage

Original-patch-by: Li Zefan <lizefan@huawei.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Lennart Poettering <lpoetter@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Aristeu Rozanski <aris@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Aristeu Rozanski 2012-08-23 16:53:28 -04:00 committed by Tejun Heo
parent fea7a08acb
commit 38f3865744
4 changed files with 229 additions and 159 deletions

View file

@ -59,7 +59,9 @@
#ifdef __KERNEL__
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/spinlock.h>
struct inode;
struct dentry;
@ -96,6 +98,52 @@ ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name,
char **xattr_value, size_t size, gfp_t flags);
int vfs_xattr_cmp(struct dentry *dentry, const char *xattr_name,
const char *value, size_t size, gfp_t flags);
struct simple_xattrs {
struct list_head head;
spinlock_t lock;
};
struct simple_xattr {
struct list_head list;
char *name;
size_t size;
char value[0];
};
/*
* initialize the simple_xattrs structure
*/
static inline void simple_xattrs_init(struct simple_xattrs *xattrs)
{
INIT_LIST_HEAD(&xattrs->head);
spin_lock_init(&xattrs->lock);
}
/*
* free all the xattrs
*/
static inline void simple_xattrs_free(struct simple_xattrs *xattrs)
{
struct simple_xattr *xattr, *node;
list_for_each_entry_safe(xattr, node, &xattrs->head, list) {
kfree(xattr->name);
kfree(xattr);
}
}
struct simple_xattr *simple_xattr_alloc(const void *value, size_t size);
int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
void *buffer, size_t size);
int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
const void *value, size_t size, int flags);
int simple_xattr_remove(struct simple_xattrs *xattrs, const char *name);
ssize_t simple_xattr_list(struct simple_xattrs *xattrs, char *buffer,
size_t size);
void simple_xattr_list_add(struct simple_xattrs *xattrs,
struct simple_xattr *new_xattr);
#endif /* __KERNEL__ */
#endif /* _LINUX_XATTR_H */