diff --git a/security/commoncap.c b/security/commoncap.c
index afd9679ca866..1156178a0c52 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -920,7 +920,7 @@ int cap_inode_setxattr(struct dentry *dentry, const char *name,
 
 	/* Ignore non-security xattrs */
 	if (strncmp(name, XATTR_SECURITY_PREFIX,
-			sizeof(XATTR_SECURITY_PREFIX) - 1) != 0)
+			XATTR_SECURITY_PREFIX_LEN) != 0)
 		return 0;
 
 	/*
@@ -952,7 +952,7 @@ int cap_inode_removexattr(struct dentry *dentry, const char *name)
 
 	/* Ignore non-security xattrs */
 	if (strncmp(name, XATTR_SECURITY_PREFIX,
-			sizeof(XATTR_SECURITY_PREFIX) - 1) != 0)
+			XATTR_SECURITY_PREFIX_LEN) != 0)
 		return 0;
 
 	if (strcmp(name, XATTR_NAME_CAPS) == 0) {