[PATCH v20 11/23] posix_acl: Improve xattr fixup code

[Andreas Gruenbacher]

Both XATTR_NAME_POSIX_ACL_ACCESS and XATTR_NAME_POSIX_ACL_DEFAULT have
the same XATTR_SYSTEM_PREFIX prefix; don't check for the same prefix
repeatedly.

Signed-off-by: Andreas Gruenbacher <agrue...@redhat.com>
---
 fs/xattr.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/fs/xattr.c b/fs/xattr.c
index 4861322..c364696 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -295,6 +295,16 @@ out:
 }
 EXPORT_SYMBOL_GPL(vfs_removexattr);
 
+static void
+fix_xattr_from_user(const char *kname, void *kvalue, size_t size)
+{
+       if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+               return;
+       kname += XATTR_SYSTEM_PREFIX_LEN;
+       if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
+           !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
+               posix_acl_fix_xattr_from_user(kvalue, size);
+}
 
 /*
  * Extended attribute SET operations
@@ -329,9 +339,7 @@ setxattr(struct dentry *d, const char __user *name, const 
void __user *value,
                        error = -EFAULT;
                        goto out;
                }
-               if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
-                   (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
-                       posix_acl_fix_xattr_from_user(kvalue, size);
+               fix_xattr_from_user(kname, kvalue, size);
        }
 
        error = vfs_setxattr(d, kname, kvalue, size, flags);
@@ -396,6 +404,17 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, 
name,
        return error;
 }
 
+static void
+fix_xattr_to_user(const char *kname, void *kvalue, size_t size)
+{
+       if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+               return;
+       kname += XATTR_SYSTEM_PREFIX_LEN;
+       if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
+           !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
+               posix_acl_fix_xattr_to_user(kvalue, size);
+}
+
 /*
  * Extended attribute GET operations
  */
@@ -426,9 +445,7 @@ getxattr(struct dentry *d, const char __user *name, void 
__user *value,
 
        error = vfs_getxattr(d, kname, kvalue, size);
        if (error > 0) {
-               if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
-                   (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
-                       posix_acl_fix_xattr_to_user(kvalue, size);
+               fix_xattr_to_user(kname, kvalue, size);
                if (size && copy_to_user(value, kvalue, error))
                        error = -EFAULT;
        } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
-- 
2.5.0