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authorZefir Kurtisi <zefir.kurtisi@neratec.com>2017-01-06 14:14:48 +0300
committerDavid S. Miller <davem@davemloft.net>2017-01-09 23:37:44 +0300
commit811a919135b980bac8009d042acdccf10dc1ef5e (patch)
treeecd9432bc1b198362749ac3209770000006c6475 /drivers/uwb/umc-bus.c
parentc92f5bdc4b9ba509a93f9e386fbb1fa779d4b0d6 (diff)
downloadlinux-811a919135b980bac8009d042acdccf10dc1ef5e.tar.xz
phy state machine: failsafe leave invalid RUNNING state
While in RUNNING state, phy_state_machine() checks for link changes by comparing phydev->link before and after calling phy_read_status(). This works as long as it is guaranteed that phydev->link is never changed outside the phy_state_machine(). If in some setups this happens, it causes the state machine to miss a link loss and remain RUNNING despite phydev->link being 0. This has been observed running a dsa setup with a process continuously polling the link states over ethtool each second (SNMPD RFC-1213 agent). Disconnecting the link on a phy followed by a ETHTOOL_GSET causes dsa_slave_get_settings() / dsa_slave_get_link_ksettings() to call phy_read_status() and with that modify the link status - and with that bricking the phy state machine. This patch adds a fail-safe check while in RUNNING, which causes to move to CHANGELINK when the link is gone and we are still RUNNING. Signed-off-by: Zefir Kurtisi <zefir.kurtisi@neratec.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/uwb/umc-bus.c')
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