On Wednesday, 24 January 2024 01:56:52 CST Arnd Bergmann wrote:

On Wed, Jan 24, 2024, at 01:40, Elizabeth Figura wrote:

quoted

+	if (args->timeout) {
+		struct timespec64 to;
+
+		if (get_timespec64(&to, u64_to_user_ptr(args->timeout)))
+			return -EFAULT;
+		if (!timespec64_valid(&to))
+			return -EINVAL;
+
+		timeout = timespec64_to_ns(&to);
+	}

Have you considered just passing the nanosecond value here?
Since you do not appear to write it back, that would avoid
the complexities of dealing with timespec layout differences
and indirection.

That'd be nicer in general. I think there was some documentation that advised
using timespec64 for new ioctl interfaces but it may have been outdated or
misread.

quoted

+	ids = kmalloc_array(count, sizeof(*ids), GFP_KERNEL);
+	if (!ids)
+		return -ENOMEM;
+	if (copy_from_user(ids, u64_to_user_ptr(args->objs),
+			   array_size(count, sizeof(*ids)))) {
+		kfree(ids);
+		return -EFAULT;
+	}

This looks like memdup_user() would be slightly simpler.

That's useful, thanks.