posix_acl: xattr representation cleanups

Remove the unnecessary typedefs and the zero-length a_entries array in
struct posix_acl_xattr_header.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 59d47ab0..8cdcbb1 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -633,15 +633,15 @@
 	struct user_namespace *to, struct user_namespace *from,
 	void *value, size_t size)
 {
-	posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
-	posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
+	struct posix_acl_xattr_header *header = value;
+	struct posix_acl_xattr_entry *entry = (void *)(header + 1), *end;
 	int count;
 	kuid_t uid;
 	kgid_t gid;
 
 	if (!value)
 		return;
-	if (size < sizeof(posix_acl_xattr_header))
+	if (size < sizeof(struct posix_acl_xattr_header))
 		return;
 	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
 		return;
@@ -691,15 +691,15 @@
 posix_acl_from_xattr(struct user_namespace *user_ns,
 		     const void *value, size_t size)
 {
-	posix_acl_xattr_header *header = (posix_acl_xattr_header *)value;
-	posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end;
+	const struct posix_acl_xattr_header *header = value;
+	const struct posix_acl_xattr_entry *entry = (const void *)(header + 1), *end;
 	int count;
 	struct posix_acl *acl;
 	struct posix_acl_entry *acl_e;
 
 	if (!value)
 		return NULL;
-	if (size < sizeof(posix_acl_xattr_header))
+	if (size < sizeof(struct posix_acl_xattr_header))
 		 return ERR_PTR(-EINVAL);
 	if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION))
 		return ERR_PTR(-EOPNOTSUPP);
@@ -760,8 +760,8 @@
 posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl,
 		   void *buffer, size_t size)
 {
-	posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer;
-	posix_acl_xattr_entry *ext_entry;
+	struct posix_acl_xattr_header *ext_acl = buffer;
+	struct posix_acl_xattr_entry *ext_entry;
 	int real_size, n;
 
 	real_size = posix_acl_xattr_size(acl->a_count);
@@ -770,7 +770,7 @@
 	if (real_size > size)
 		return -ERANGE;
 
-	ext_entry = ext_acl->a_entries;
+	ext_entry = (void *)(ext_acl + 1);
 	ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION);
 
 	for (n=0; n < acl->a_count; n++, ext_entry++) {