Re: [PATCH net 2/2] net: macb: reject an unknown link speed in the taprio setup
From: Aleksei Sviridkin <hidden>
Date: 2026-09-04 23:45:37
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On Wed, 2 Sep 2026 18:37, Andrew Lunn wrote:
Can ethtool_validate_speed() be used?
No, it returns true for SPEED_UNKNOWN:
static inline int ethtool_validate_speed(__u32 speed)
{
return speed <= __KERNEL_INT_MAX || speed == (__u32)SPEED_UNKNOWN;
}
It answers "is this a legal encoding of a speed", which is the question
you want when a speed arrives from userspace, and that is where its
callers use it: net/ethtool/ioctl.c and otx2_ethtool.c both validate
what was passed in.
Here the speed goes the other way. We read it back and need it usable,
and SPEED_UNKNOWN is a legal encoding of something unusable, so the
helper would accept the one value the patch exists to reject.
v2 is coming with the commit message Théo asked for.