Re: [net-next,v3,01/11] net: phy: phy_port: Correctly recompute the port's linkmodes
From: Simon Horman <horms@kernel.org>
Date: 2026-02-03 17:58:24
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This is an AI-generated review of your patch. The human sending this email has considered the AI review valid, or at least plausible. For local reproduction steps see https://netdev-ai.bots.linux.dev/ai-local.html --- net: phy: phy_port: Correctly recompute the port's linkmodes This commit fixes phy_port_update_supported() to properly filter linkmodes instead of incorrectly or'ing medium-specific modes to the existing support. It moves the medium iteration inside a check for empty port->supported. Fixes: 589e934d2735 ("net: phy: Introduce PHY ports representation")
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/phy/phy_port.c b/drivers/net/phy/phy_port.c --- a/drivers/net/phy/phy_port.c +++ b/drivers/net/phy/phy_port.c
[ ... ]
quoted hunk ↗ jump to hunk
@@ -132,6 +126,19 @@ void phy_port_update_supported(struct phy_port *port) port->pairs = max_t(int, port->pairs, ethtool_linkmode_n_pairs(mode)); + if (linkmode_empty(port->supported)) { + for_each_set_bit(i, &port->mediums, + __ETHTOOL_LINK_MEDIUM_LAST) { + __ETHTOOL_DECLARE_LINK_MODE_MASK(med_supported) = {0}; + + phy_caps_medium_get_supported(med_supported, i, + port->pairs); + linkmode_or(supported, supported, med_supported); + } + + linkmode_and(port->supported, port->supported, supported); + }
Jakub Kicinski raised a concern in v2 about the AND operation when
port->supported starts empty. The v3 fix adds the
'if (linkmode_empty(port->supported))' check, but then still performs:
linkmode_and(port->supported, port->supported, supported);
inside that block. Since we just confirmed port->supported is empty,
ANDing it with anything will always produce an empty result.
Should this be linkmode_copy() or linkmode_or() instead of linkmode_and()
when port->supported starts empty?
Reference: https://lore.kernel.org/all/20260130040009.707764-1-kuba@kernel.org/ (local)