[PATCH 6/7] powerpc/eeh: Allow disabling recovery

[Oliver O'Halloran]

Currently when we detect an error we automatically invoke the EEH recovery
handler. This can be annoying when debugging EEH problems, or when working
on EEH itself so this patch adds a debugfs knob that will prevent a
recovery event from being queued up when an issue is detected.

Signed-off-by: Oliver O'Halloran <oohall at gmail.com>
---
 arch/powerpc/include/asm/eeh.h  |  1 +
 arch/powerpc/kernel/eeh.c       | 11 +++++++++++
 arch/powerpc/kernel/eeh_event.c |  9 +++++++++
 3 files changed, 21 insertions(+)

diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
index fc21b6e78e91..6f6721561302 100644
--- a/arch/powerpc/include/asm/eeh.h
+++ b/arch/powerpc/include/asm/eeh.h
@@ -220,6 +220,7 @@ struct eeh_ops {
 
 extern int eeh_subsystem_flags;
 extern uint32_t eeh_max_freezes;
+extern bool eeh_debugfs_no_recover;
 extern struct eeh_ops *eeh_ops;
 extern raw_spinlock_t confirm_error_lock;
 
diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
index d1f0bdf41fac..92809b137e39 100644
--- a/arch/powerpc/kernel/eeh.c
+++ b/arch/powerpc/kernel/eeh.c
@@ -111,6 +111,13 @@ EXPORT_SYMBOL(eeh_subsystem_flags);
  */
 uint32_t eeh_max_freezes = 5;
 
+/*
+ * Controls whether a recovery event should be scheduled when an
+ * isolated device is discovered. This is only really useful for
+ * debugging problems with the EEH core.
+ */
+bool eeh_debugfs_no_recover;
+
 /* Platform dependent EEH operations */
 struct eeh_ops *eeh_ops = NULL;
 
@@ -1810,7 +1817,11 @@ static int __init eeh_init_proc(void)
 					   &eeh_enable_dbgfs_ops);
 		debugfs_create_u32("eeh_max_freezes", 0600,
 				powerpc_debugfs_root, &eeh_max_freezes);
+		debugfs_create_bool("eeh_disable_recovery", 0600,
+				powerpc_debugfs_root,
+				&eeh_debugfs_no_recover);
 		eeh_cache_debugfs_init();
+#endif
 	}
 
 	return 0;
diff --git a/arch/powerpc/kernel/eeh_event.c b/arch/powerpc/kernel/eeh_event.c
index 227e57f980df..19837798bb1d 100644
--- a/arch/powerpc/kernel/eeh_event.c
+++ b/arch/powerpc/kernel/eeh_event.c
@@ -126,6 +126,15 @@ int eeh_send_failure_event(struct eeh_pe *pe)
 	unsigned long flags;
 	struct eeh_event *event;
 
+	/*
+	 * If we've manually supressed recovery events via debugfs
+	 * then just drop it on the floor.
+	 */
+	if (eeh_debugfs_no_recover) {
+		pr_err("EEH: Event dropped due to no_recover setting\n");
+		return 0;
+	}
+
 	event = kzalloc(sizeof(*event), GFP_ATOMIC);
 	if (!event) {
 		pr_err("EEH: out of memory, event not handled\n");
-- 
2.20.1