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Subject[PATCH] PHYLIB: Fix an interrupt loop potential when halting
 Ensure the PHY_HALTED state is not entered with the IRQ asserted as it 
could lead to an interrupt loop.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
---
There is a small window in phy_stop(), where the state of the PHY machine
indicates it has been halted, but its interrupt output might still be
unmasked. If an interrupt goes active right at this moment it will loop
as the phy_interrupt() handler exits immediately with IRQ_NONE if the
halted state is seen. It is unsafe to extend the phydev spinlock to cover
phy_interrupt(). It is safe to swap the order of the actions though as
all the competing places to unmask the interrupt output of the PHY, which
are phy_change() and phy_timer() are already covered with the lock as is
the sequence in question.

Checked with checkpatch.pl and at the run time.

Please apply.

Maciej

patch-mips-2.6.23-rc5-20070904-phy-halt-0
diff -up --recursive --new-file linux-mips-2.6.23-rc5-20070904.macro/drivers/net/phy/phy.c linux-mips-2.6.23-rc5-20070904/drivers/net/phy/phy.c
--- linux-mips-2.6.23-rc5-20070904.macro/drivers/net/phy/phy.c 2007-09-04 04:55:42.000000000 +0000
+++ linux-mips-2.6.23-rc5-20070904/drivers/net/phy/phy.c 2007-09-16 17:17:20.000000000 +0000
@@ -722,8 +722,6 @@ void phy_stop(struct phy_device *phydev)
if (PHY_HALTED == phydev->state)
goto out_unlock;

- phydev->state = PHY_HALTED;
-
if (phydev->irq != PHY_POLL) {
/* Disable PHY Interrupts */
phy_config_interrupt(phydev, PHY_INTERRUPT_DISABLED);
@@ -732,6 +730,8 @@ void phy_stop(struct phy_device *phydev)
phy_clear_interrupt(phydev);
}

+ phydev->state = PHY_HALTED;
+
out_unlock:
spin_unlock(&phydev->lock);

-
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