On Thu, Feb 11, 2016 at 03:37:55PM -0700, Baicar, Tyler wrote:

On 2/10/2016 11:03 AM, Will Deacon wrote:

quoted

On Fri, Feb 05, 2016 at 12:13:28PM -0700, Tyler Baicar wrote:

quoted

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 6c68100..ed64b97 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c

@@ -50,6 +50,10 @@
 #include <acpi/apei.h>
 #include <asm/tlbflush.h>
+#ifdef CONFIG_HAVE_ACPI_APEI_SEA
+#include <asm/system_misc.h>
+#endif
+
 #include "apei-internal.h"
 #define GHES_PFX	"GHES: "

@@ -784,6 +788,62 @@ static struct notifier_block ghes_notifier_sci = {
 	.notifier_call = ghes_notify_sci,
 };
+#ifdef CONFIG_HAVE_ACPI_APEI_SEA
+static LIST_HEAD(ghes_sea);
+
+static int ghes_notify_sea(struct notifier_block *this,
+				  unsigned long event, void *data)
+{
+	struct ghes *ghes;
+	int ret = NOTIFY_DONE;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(ghes, &ghes_sea, list) {
+		if (!ghes_proc(ghes))
+			ret = NOTIFY_OK;
+	}
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static struct notifier_block ghes_notifier_sea = {
+	.notifier_call = ghes_notify_sea,
+};
+
+static int ghes_sea_add(struct ghes *ghes)
+{
+	mutex_lock(&ghes_list_mutex);

Can you just use spin_lock, to be consistent with our other excception
hooks?

This mutex is being used throughout ghes.c for editing the lists, so I think
this is the proper (or at least consistent) implementation. This mutex was
defined specifically for editing the lists according to the comment above
the mutex definition:

"All error sources notified with SCI shares one notifier function, so they
need to be linked and checked one by one. This is applied to NMI too. RCU is
used for these lists, so ghes_list_mutex is only used for list changing, not
for traversing."

The use of this mutex is identical to the way that SCI and NMI use it when
adding or deleting from the lists. Should I add to this comment that this
applies to SEA as well?

No, it's fine. I overlooked the fact that this was under drivers/acpi/,
so if you're consistent with other code under there then there's no need
to change anything.

Will