Commit d4e6cb32 authored by Maxime Chevallier's avatar Maxime Chevallier Committed by Jakub Kicinski
Browse files

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: default avatarJijie Shao <shaojijie@huawei.com>
Closes: https://lore.kernel.org/netdev/20250603102500.4ec743cf@fedora/T/#m22ed60ca635c67dc7d9cbb47e8995b2beb5c1576


Tested-by: default avatarJijie Shao <shaojijie@huawei.com>
Reviewed-by: default avatarLarysa Zaremba <larysa.zaremba@intel.com>
Fixes: fc81e257 ("net: phy: phy_caps: Allow looking-up link caps based on speed and duplex")
Signed-off-by: default avatarMaxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20250606094321.483602-1-maxime.chevallier@bootlin.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 27cea0e4

drivers/net/phy/phy_caps.c

+12 −6
Original line number Diff line number Diff line
@@ -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);