path: root/include
diff options
authorMaciej W. Rozycki <macro@linux-mips.org>2007-09-28 22:42:14 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-10-10 16:53:55 -0700
commit0ac49527318bc388a881152d60f49d7951606024 (patch)
tree64b99a7543c913ff17344259b3938d6a5702ef69 /include
parentforcedeth: "no link" is informational (diff)
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 Now that the call to flush_work_keventd() (problematic because of rtnl_mutex being held) has been replaced by cancel_work_sync() another issue has arisen and been left unresolved.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 <macro@linux-mips.org> Cc: Andy Fleming <afleming@freescale.com> Cc: Jeff Garzik <jgarzik@pobox.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jeff Garzik <jeff@garzik.org>
Diffstat (limited to 'include')
1 files changed, 3 insertions, 0 deletions
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 <linux/timer.h>
#include <linux/workqueue.h>
+#include <asm/atomic.h>
#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;