[PATCH] powerpc/pseries: mutex lock to serialize EEH event processing
This forces the processing of EEH PCI events to be serialized,
using a very simple mutex lock. This serialization is required to
avoid races involving additional PCI device failures that may occur
during the recovery phase of a previous failure.
Signed-off-by: Linas Vepstas <linas@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/platforms/pseries/eeh_event.c b/arch/powerpc/platforms/pseries/eeh_event.c
index 9a9961f..a1bda6f 100644
--- a/arch/powerpc/platforms/pseries/eeh_event.c
+++ b/arch/powerpc/platforms/pseries/eeh_event.c
@@ -19,7 +19,9 @@
*/
#include <linux/list.h>
+#include <linux/mutex.h>
#include <linux/pci.h>
+#include <linux/workqueue.h>
#include <asm/eeh_event.h>
#include <asm/ppc-pci.h>
@@ -37,14 +39,18 @@
static void eeh_thread_launcher(void *);
DECLARE_WORK(eeh_event_wq, eeh_thread_launcher, NULL);
+/* Serialize reset sequences for a given pci device */
+DEFINE_MUTEX(eeh_event_mutex);
+
/**
- * eeh_event_handler - dispatch EEH events. The detection of a frozen
- * slot can occur inside an interrupt, where it can be hard to do
- * anything about it. The goal of this routine is to pull these
- * detection events out of the context of the interrupt handler, and
- * re-dispatch them for processing at a later time in a normal context.
- *
+ * eeh_event_handler - dispatch EEH events.
* @dummy - unused
+ *
+ * The detection of a frozen slot can occur inside an interrupt,
+ * where it can be hard to do anything about it. The goal of this
+ * routine is to pull these detection events out of the context
+ * of the interrupt handler, and re-dispatch them for processing
+ * at a later time in a normal context.
*/
static int eeh_event_handler(void * dummy)
{
@@ -64,23 +70,24 @@
event = list_entry(eeh_eventlist.next, struct eeh_event, list);
list_del(&event->list);
}
-
- if (event)
- eeh_mark_slot(event->dn, EEH_MODE_RECOVERING);
-
spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
+
if (event == NULL)
break;
+ /* Serialize processing of EEH events */
+ mutex_lock(&eeh_event_mutex);
+ eeh_mark_slot(event->dn, EEH_MODE_RECOVERING);
+
printk(KERN_INFO "EEH: Detected PCI bus error on device %s\n",
pci_name(event->dev));
handle_eeh_events(event);
eeh_clear_slot(event->dn, EEH_MODE_RECOVERING);
-
pci_dev_put(event->dev);
kfree(event);
+ mutex_unlock(&eeh_event_mutex);
}
return 0;
@@ -88,7 +95,6 @@
/**
* eeh_thread_launcher
- *
* @dummy - unused
*/
static void eeh_thread_launcher(void *dummy)