revert "memfd: improve userspace warnings for missing exec-related flags".

This warning is telling userspace developers to pass MFD_EXEC and
MFD_NOEXEC_SEAL to memfd_create().  Commit 434ed3350f ("memfd: improve
userspace warnings for missing exec-related flags") made the warning more
frequent and visible in the hope that this would accelerate the fixing of
errant userspace.

But the overall effect is to generate far too much dmesg noise.

Fixes: 434ed3350f ("memfd: improve userspace warnings for missing exec-related flags")
Reported-by: Damian Tometzki <[email protected]>
Closes: https://lkml.kernel.org/r/[email protected]
Cc: Aleksa Sarai <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: Daniel Verkamp <[email protected]>
Cc: Jeff Xu <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

mm/memfd.c

@@ -316,7 +316,7 @@ SYSCALL_DEFINE2(memfd_create,
 		return -EINVAL;
 
 	if (!(flags & (MFD_EXEC | MFD_NOEXEC_SEAL))) {
-		pr_info_ratelimited(
+		pr_warn_once(
 			"%s[%d]: memfd_create() called without MFD_EXEC or MFD_NOEXEC_SEAL set\n",
 			current->comm, task_pid_nr(current));
 	}