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Commit 8c33fd11 authored by Linas Vepstas's avatar Linas Vepstas Committed by Paul Mackerras
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[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: default avatarLinas Vepstas <linas@austin.ibm.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent f18dd516

arch/powerpc/platforms/pseries/eeh_event.c

+18 −12
Original line number Diff line number Diff line
@@ -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 @@ LIST_HEAD(eeh_eventlist); 
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 @@ static int eeh_event_handler(void * dummy) 
			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 @@ static int eeh_event_handler(void * dummy) 


/**

 * eeh_thread_launcher

 *

 * @dummy - unused

 */

static void eeh_thread_launcher(void *dummy)