Re: [PATCH net-2.6] 3c59x: Remove incorrect locking; correct documented lock hierarchy
From: David Miller <davem@davemloft.net>
Date: 2010-09-01 21:37:58
From: David Miller <davem@davemloft.net>
Date: 2010-09-01 21:37:58
From: Ben Hutchings <redacted> Date: Tue, 31 Aug 2010 01:15:33 +0100
vortex_ioctl() was grabbing vortex_private::lock around its call to
generic_mii_ioctl(). This is no longer necessary since there are more
specific locks which the mdio_{read,write}() functions will obtain.
Worse, those functions do not save and restore IRQ flags when locking
the MII state, so interrupts will be enabled when generic_mii_ioctl()
returns.
Since there is currently no need for any function to call
mdio_{read,write}() while holding another spinlock, do not change them
to save and restore IRQ flags but remove the specification of ordering
between vortex_private::lock and vortex_private::mii_lock.
Signed-off-by: Ben Hutchings <redacted>
---
I've now borrowed a card to test 3c59x on. I've seen another regression
reported <http://bugs.debian.org/586967> after my locking changes, which
I can't reproduce.I think the lock is necessary, in some form. Nothing otherwise protects vp->mii, which is accessed and modified by not just this ioctl, but also ethtool operation calls. So we can't apply your patch as-is.