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author | Lukas Wunner <lukas@wunner.de> | 2022-06-28 13:15:08 +0300 |
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committer | Jakub Kicinski <kuba@kernel.org> | 2022-06-30 06:38:52 +0300 |
commit | 1758bde2e4aa5ff188d53e7d9d388bbb7e12eebb (patch) | |
tree | 535ca40e10a9352a71475d2ff5f29e0bcb6609d7 /include | |
parent | e65af5403e462ccd7dff6a045a886c64da598c2e (diff) | |
download | linux-1758bde2e4aa5ff188d53e7d9d388bbb7e12eebb.tar.xz |
net: phy: Don't trigger state machine while in suspend
Upon system sleep, mdio_bus_phy_suspend() stops the phy_state_machine(),
but subsequent interrupts may retrigger it:
They may have been left enabled to facilitate wakeup and are not
quiesced until the ->suspend_noirq() phase. Unwanted interrupts may
hence occur between mdio_bus_phy_suspend() and dpm_suspend_noirq(),
as well as between dpm_resume_noirq() and mdio_bus_phy_resume().
Retriggering the phy_state_machine() through an interrupt is not only
undesirable for the reason given in mdio_bus_phy_suspend() (freezing it
midway with phydev->lock held), but also because the PHY may be
inaccessible after it's suspended: Accesses to USB-attached PHYs are
blocked once usb_suspend_both() clears the can_submit flag and PHYs on
PCI network cards may become inaccessible upon suspend as well.
Amend phy_interrupt() to avoid triggering the state machine if the PHY
is suspended. Signal wakeup instead if the attached net_device or its
parent has been configured as a wakeup source. (Those conditions are
identical to mdio_bus_phy_may_suspend().) Postpone handling of the
interrupt until the PHY has resumed.
Before stopping the phy_state_machine() in mdio_bus_phy_suspend(),
wait for a concurrent phy_interrupt() to run to completion. That is
necessary because phy_interrupt() may have checked the PHY's suspend
status before the system sleep transition commenced and it may thus
retrigger the state machine after it was stopped.
Likewise, after re-enabling interrupt handling in mdio_bus_phy_resume(),
wait for a concurrent phy_interrupt() to complete to ensure that
interrupts which it postponed are properly rerun.
The issue was exposed by commit 1ce8b37241ed ("usbnet: smsc95xx: Forward
PHY interrupts to PHY driver to avoid polling"), but has existed since
forever.
Fixes: 541cd3ee00a4 ("phylib: Fix deadlock on resume")
Link: https://lore.kernel.org/netdev/a5315a8a-32c2-962f-f696-de9a26d30091@samsung.com/
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: stable@vger.kernel.org # v2.6.33+
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/b7f386d04e9b5b0e2738f0125743e30676f309ef.1656410895.git.lukas@wunner.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/phy.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/phy.h b/include/linux/phy.h index 508f1149665b..b09f7d36cff2 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -572,6 +572,10 @@ struct macsec_ops; * @mdix_ctrl: User setting of crossover * @pma_extable: Cached value of PMA/PMD Extended Abilities Register * @interrupts: Flag interrupts have been enabled + * @irq_suspended: Flag indicating PHY is suspended and therefore interrupt + * handling shall be postponed until PHY has resumed + * @irq_rerun: Flag indicating interrupts occurred while PHY was suspended, + * requiring a rerun of the interrupt handler after resume * @interface: enum phy_interface_t value * @skb: Netlink message for cable diagnostics * @nest: Netlink nest used for cable diagnostics @@ -626,6 +630,8 @@ struct phy_device { /* Interrupts are enabled */ unsigned interrupts:1; + unsigned irq_suspended:1; + unsigned irq_rerun:1; enum phy_state state; |