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vfs: start hiding vfsmount guts series 

Almost all fields of struct vfsmount are used only by core VFS (and
a fairly small part of it, at that).  The plan: embed struct vfsmount
into struct mount, making the latter visible only to core parts of VFS.
Then move fields from vfsmount to mount, eventually leaving only
mnt_root/mnt_sb/mnt_flags in struct vfsmount.  Filesystem code still
gets pointers to struct vfsmount and remains unchanged; all such
pointers go to struct vfsmount embedded into the instances of struct
mount allocated by fs/namespace.c.  When fs/namespace.c et.al. get
a pointer to vfsmount, they turn it into pointer to mount (using
container_of) and work with that.

This is the first part of series; struct mount is introduced,
allocation switched to using it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
wifi-calibration
Al Viro 2011-11-23 12:14:10 -05:00
parent dabe0dc194
commit 7d6fec45a5
2 changed files with 19 additions and 8 deletions
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9
fs/mount.h
View File

@ -1,5 +1,14 @@
#include <linux/mount.h> #include <linux/mount.h>
struct mount {
struct vfsmount mnt;
};
static inline struct mount *real_mount(struct vfsmount *mnt)
{
return container_of(mnt, struct mount, mnt);
}
static inline int mnt_has_parent(struct vfsmount *mnt) static inline int mnt_has_parent(struct vfsmount *mnt)
{ {
return mnt != mnt->mnt_parent; return mnt != mnt->mnt_parent;

18
fs/namespace.c
View File

@ -173,8 +173,9 @@ unsigned int mnt_get_count(struct vfsmount *mnt)
static struct vfsmount *alloc_vfsmnt(const char *name) static struct vfsmount *alloc_vfsmnt(const char *name)
{ {
struct vfsmount *mnt = kmem_cache_zalloc(mnt_cache, GFP_KERNEL); struct mount *p = kmem_cache_zalloc(mnt_cache, GFP_KERNEL);
if (mnt) { if (p) {
struct vfsmount *mnt = &p->mnt;
int err; int err;
err = mnt_alloc_id(mnt); err = mnt_alloc_id(mnt);
@ -210,16 +211,16 @@ static struct vfsmount *alloc_vfsmnt(const char *name)
INIT_HLIST_HEAD(&mnt->mnt_fsnotify_marks); INIT_HLIST_HEAD(&mnt->mnt_fsnotify_marks);
#endif #endif
} }
return mnt; return &p->mnt;
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
out_free_devname: out_free_devname:
kfree(mnt->mnt_devname); kfree(p->mnt.mnt_devname);
#endif #endif
out_free_id: out_free_id:
mnt_free_id(mnt); mnt_free_id(&p->mnt);
out_free_cache: out_free_cache:
kmem_cache_free(mnt_cache, mnt); kmem_cache_free(mnt_cache, p);
return NULL; return NULL;
} }
@ -449,12 +450,13 @@ static void __mnt_unmake_readonly(struct vfsmount *mnt)
static void free_vfsmnt(struct vfsmount *mnt) static void free_vfsmnt(struct vfsmount *mnt)
{ {
struct mount *p = real_mount(mnt);
kfree(mnt->mnt_devname); kfree(mnt->mnt_devname);
mnt_free_id(mnt); mnt_free_id(mnt);
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
free_percpu(mnt->mnt_pcp); free_percpu(mnt->mnt_pcp);
#endif #endif
kmem_cache_free(mnt_cache, mnt); kmem_cache_free(mnt_cache, p);
} }
/* /*
@ -2698,7 +2700,7 @@ void __init mnt_init(void)
init_rwsem(&namespace_sem); init_rwsem(&namespace_sem);
mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct vfsmount), mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct mount),
0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
mount_hashtable = (struct list_head *)__get_free_page(GFP_ATOMIC); mount_hashtable = (struct list_head *)__get_free_page(GFP_ATOMIC);