From d4e6cb324dcc952618fec6b25aa3fc7bfc2750b4 Mon Sep 17 00:00:00 2001 From: Maxime Chevallier Date: Fri, 6 Jun 2025 11:43:20 +0200 Subject: [PATCH] net: phy: phy_caps: Don't skip better duplex macth on non-exact match When performing a non-exact phy_caps lookup, we are looking for a supported mode that matches as closely as possible the passed speed/duplex. Blamed patch broke that logic by returning a match too early in case the caller asks for half-duplex, as a full-duplex linkmode may match first, and returned as a non-exact match without even trying to mach on half-duplex modes. Reported-by: Jijie Shao Closes: https://lore.kernel.org/netdev/20250603102500.4ec743cf@fedora/T/#m22ed60ca635c67dc7d9cbb47e8995b2beb5c1576 Tested-by: Jijie Shao Reviewed-by: Larysa Zaremba Fixes: fc81e257d19f ("net: phy: phy_caps: Allow looking-up link caps based on speed and duplex") Signed-off-by: Maxime Chevallier Link: https://patch.msgid.link/20250606094321.483602-1-maxime.chevallier@bootlin.com Signed-off-by: Jakub Kicinski --- drivers/net/phy/phy_caps.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/drivers/net/phy/phy_caps.c b/drivers/net/phy/phy_caps.c index 703321689726..38417e288611 100644 --- a/drivers/net/phy/phy_caps.c +++ b/drivers/net/phy/phy_caps.c @@ -188,6 +188,9 @@ phy_caps_lookup_by_linkmode_rev(const unsigned long *linkmodes, bool fdx_only) * When @exact is not set, we return either an exact match, or matching capabilities * at lower speed, or the lowest matching speed, or NULL. * + * Non-exact matches will try to return an exact speed and duplex match, but may + * return matching capabilities with same speed but a different duplex. + * * Returns: a matched link_capabilities according to the above process, NULL * otherwise. */ @@ -195,7 +198,7 @@ const struct link_capabilities * phy_caps_lookup(int speed, unsigned int duplex, const unsigned long *supported, bool exact) { - const struct link_capabilities *lcap, *last = NULL; + const struct link_capabilities *lcap, *match = NULL, *last = NULL; for_each_link_caps_desc_speed(lcap) { if (linkmode_intersects(lcap->linkmodes, supported)) { @@ -204,16 +207,19 @@ phy_caps_lookup(int speed, unsigned int duplex, const unsigned long *supported, if (lcap->speed == speed && lcap->duplex == duplex) { return lcap; } else if (!exact) { - if (lcap->speed <= speed) - return lcap; + if (!match && lcap->speed <= speed) + match = lcap; + + if (lcap->speed < speed) + break; } } } - if (!exact) - return last; + if (!match && !exact) + match = last; - return NULL; + return match; } EXPORT_SYMBOL_GPL(phy_caps_lookup); -- 2.25.1