From 0ac49527318bc388a881152d60f49d7951606024 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Fri, 28 Sep 2007 22:42:14 -0700 Subject: PHYLIB: IRQ event workqueue handling fixes Keep track of disable_irq_nosync() invocations and call enable_irq() the right number of times if work has been cancelled that would include them. Now that the call to flush_work_keventd() (problematic because of rtnl_mutex being held) has been replaced by cancel_work_sync() another issue has arisen and been left unresolved. As the MDIO bus cannot be accessed from the interrupt context the PHY interrupt handler uses disable_irq_nosync() to prevent from looping and schedules some work to be done as a softirq, which, apart from handling the state change of the originating PHY, is responsible for reenabling the interrupt. Now if the interrupt line is shared by another device and a call to the softirq handler has been cancelled, that call to enable_irq() never happens and the other device cannot use its interrupt anymore as its stuck disabled. I decided to use a counter rather than a flag because there may be more than one call to phy_change() cancelled in the queue -- a real one and a fake one triggered by free_irq() if DEBUG_SHIRQ is used, if nothing else. Therefore because of its nesting property enable_irq() has to be called the right number of times to match the number disable_irq_nosync() was called and restore the original state. This DEBUG_SHIRQ feature is also the reason why free_irq() has to be called before cancel_work_sync(). While at it I updated the comment about phy_stop_interrupts() being called from `keventd' -- this is no longer relevant as the use of cancel_work_sync() makes such an approach unnecessary. OTOH a similar comment referring to flush_scheduled_work() in phy_stop() still applies as using cancel_work_sync() there would be dangerous. Checked with checkpatch.pl and at the run time (with and without DEBUG_SHIRQ). Signed-off-by: Maciej W. Rozycki Cc: Andy Fleming Cc: Jeff Garzik Signed-off-by: Andrew Morton Signed-off-by: Jeff Garzik --- include/linux/phy.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include') diff --git a/include/linux/phy.h b/include/linux/phy.h index 2a659789f9ca..f0742b6aaa64 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -25,6 +25,8 @@ #include #include +#include + #define PHY_BASIC_FEATURES (SUPPORTED_10baseT_Half | \ SUPPORTED_10baseT_Full | \ SUPPORTED_100baseT_Half | \ @@ -281,6 +283,7 @@ struct phy_device { /* Interrupt and Polling infrastructure */ struct work_struct phy_queue; struct timer_list phy_timer; + atomic_t irq_disable; spinlock_t lock; -- cgit v1.2.3-59-g8ed1b