powerpc/powernv: Fix killed EEH event

On PowerNV platform, EEH errors are reported by IO accessors or poller
driven by interrupt. After the PE is isolated, we won't produce EEH
event for the PE. The current implementation has possibility of EEH
event lost in this way:

The interrupt handler queues one "special" event, which drives the poller.
EEH thread doesn't pick the special event yet. IO accessors kicks in, the
frozen PE is marked as "isolated" and EEH event is queued to the list.
EEH thread runs because of special event and purge all existing EEH events.
However, we never produce an other EEH event for the frozen PE. Eventually,
the PE is marked as "isolated" and we don't have EEH event to recover it.

The patch fixes the issue to keep EEH events for PEs that have been
marked as "isolated" with the help of additional "force" help to
eeh_remove_event().

Reported-by: Rolf Brudeseth <rolfb@us.ibm.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/include/asm/eeh_event.h b/arch/powerpc/include/asm/eeh_event.h
index 89d5670b2eeb400ec659793fc3e960cc6d5894a3..1e551a2d6f8257f3fc78a73152ef65a3ebe24e52 100644 (file)
--- a/arch/powerpc/include/asm/eeh_event.h
+++ b/arch/powerpc/include/asm/eeh_event.h
@@ -33,7 +33,7 @@ struct eeh_event {
 
 int eeh_event_init(void);
 int eeh_send_failure_event(struct eeh_pe *pe);
-void eeh_remove_event(struct eeh_pe *pe);
+void eeh_remove_event(struct eeh_pe *pe, bool force);
 void eeh_handle_event(struct eeh_pe *pe);
 
 #endif /* __KERNEL__ */

diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
index 8bb40e7cdeb6a65e13bc57647f0e2b2dfd0ad430..420da61d4ce001d74ba64b675f8615b65f6e812a 100644 (file)
--- a/arch/powerpc/kernel/eeh_driver.c
+++ b/arch/powerpc/kernel/eeh_driver.c
@@ -770,7 +770,7 @@ static void eeh_handle_special_event(void)
                        eeh_serialize_lock(&flags);
 
                        /* Purge all events */
-                       eeh_remove_event(NULL);
+                       eeh_remove_event(NULL, true);
 
                        list_for_each_entry(hose, &hose_list, list_node) {
                                phb_pe = eeh_phb_pe_get(hose);
@@ -789,7 +789,7 @@ static void eeh_handle_special_event(void)
                        eeh_serialize_lock(&flags);
 
                        /* Purge all events of the PHB */
-                       eeh_remove_event(pe);
+                       eeh_remove_event(pe, true);
 
                        if (rc == EEH_NEXT_ERR_DEAD_PHB)
                                eeh_pe_state_mark(pe, EEH_PE_ISOLATED);

diff --git a/arch/powerpc/kernel/eeh_event.c b/arch/powerpc/kernel/eeh_event.c
index 72d748b56c86b2b9ae960e49b819dfedef36f61a..4eefb6e34dbb2f6edbf4990349e9c11b0b5d07f8 100644 (file)
--- a/arch/powerpc/kernel/eeh_event.c
+++ b/arch/powerpc/kernel/eeh_event.c
@@ -152,24 +152,33 @@ int eeh_send_failure_event(struct eeh_pe *pe)
 /**
  * eeh_remove_event - Remove EEH event from the queue
  * @pe: Event binding to the PE
+ * @force: Event will be removed unconditionally
  *
  * On PowerNV platform, we might have subsequent coming events
  * is part of the former one. For that case, those subsequent
  * coming events are totally duplicated and unnecessary, thus
  * they should be removed.
  */
-void eeh_remove_event(struct eeh_pe *pe)
+void eeh_remove_event(struct eeh_pe *pe, bool force)
 {
        unsigned long flags;
        struct eeh_event *event, *tmp;
 
+       /*
+        * If we have NULL PE passed in, we have dead IOC
+        * or we're sure we can report all existing errors
+        * by the caller.
+        *
+        * With "force", the event with associated PE that
+        * have been isolated, the event won't be removed
+        * to avoid event lost.
+        */
        spin_lock_irqsave(&eeh_eventlist_lock, flags);
        list_for_each_entry_safe(event, tmp, &eeh_eventlist, list) {
-               /*
-                * If we don't have valid PE passed in, that means
-                * we already have event corresponding to dead IOC
-                * and all events should be purged.
-                */
+               if (!force && event->pe &&
+                   (event->pe->state & EEH_PE_ISOLATED))
+                       continue;
+
                if (!pe) {
                        list_del(&event->list);
                        kfree(event);

diff --git a/arch/powerpc/platforms/powernv/eeh-ioda.c b/arch/powerpc/platforms/powernv/eeh-ioda.c
index 5711f6f1fda66d3fc09ac8ce931b5b5a929aaee6..9c002099f875f7414bffe025a0a31f86694a90d5 100644 (file)
--- a/arch/powerpc/platforms/powernv/eeh-ioda.c
+++ b/arch/powerpc/platforms/powernv/eeh-ioda.c
@@ -717,7 +717,7 @@ static int ioda_eeh_next_error(struct eeh_pe **pe)
         * And we should keep the cached OPAL notifier event sychronized
         * between the kernel and firmware.
         */
-       eeh_remove_event(NULL);
+       eeh_remove_event(NULL, false);
        opal_notifier_update_evt(OPAL_EVENT_PCI_ERROR, 0x0ul);
 
        list_for_each_entry(hose, &hose_list, list_node) {