powerpc: Fix PS3 allmodconfig warning

The struct ps3_notification_device in the ps3_probe_thread routine
is too large to be on the stack, causing a warning for an
allmodconfig build with clang.

Change the struct ps3_notification_device from a variable on the stack
to a dynamically allocated variable.
Reported-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/d64f06f4-81ae-4ec5-ab3b-d7f7f091e0ac@infradead.org

arch/powerpc/platforms/ps3/device-init.c

@@ -770,49 +770,51 @@ static struct task_struct *probe_task;
 
 static int ps3_probe_thread(void *data)
 {
+	struct {
 		struct ps3_notification_device dev;
+		u8 buf[512];
+	} *local;
+	struct ps3_notify_cmd *notify_cmd;
+	struct ps3_notify_event *notify_event;
 	int res;
 	unsigned int irq;
 	u64 lpar;
-	void *buf;
-	struct ps3_notify_cmd *notify_cmd;
-	struct ps3_notify_event *notify_event;
 
 	pr_debug(" -> %s:%u: kthread started\n", __func__, __LINE__);
 
-	buf = kzalloc(512, GFP_KERNEL);
-	if (!buf)
+	local = kzalloc(sizeof(*local), GFP_KERNEL);
+	if (!local)
 		return -ENOMEM;
 
-	lpar = ps3_mm_phys_to_lpar(__pa(buf));
-	notify_cmd = buf;
-	notify_event = buf;
+	lpar = ps3_mm_phys_to_lpar(__pa(&local->buf));
+	notify_cmd = (struct ps3_notify_cmd *)&local->buf;
+	notify_event = (struct ps3_notify_event *)&local->buf;
 
 	/* dummy system bus device */
-	dev.sbd.bus_id = (u64)data;
-	dev.sbd.dev_id = PS3_NOTIFICATION_DEV_ID;
-	dev.sbd.interrupt_id = PS3_NOTIFICATION_INTERRUPT_ID;
+	local->dev.sbd.bus_id = (u64)data;
+	local->dev.sbd.dev_id = PS3_NOTIFICATION_DEV_ID;
+	local->dev.sbd.interrupt_id = PS3_NOTIFICATION_INTERRUPT_ID;
 
-	res = lv1_open_device(dev.sbd.bus_id, dev.sbd.dev_id, 0);
+	res = lv1_open_device(local->dev.sbd.bus_id, local->dev.sbd.dev_id, 0);
 	if (res) {
 		pr_err("%s:%u: lv1_open_device failed %s\n", __func__,
 		       __LINE__, ps3_result(res));
 		goto fail_free;
 	}
 
-	res = ps3_sb_event_receive_port_setup(&dev.sbd, PS3_BINDING_CPU_ANY,
-					      &irq);
+	res = ps3_sb_event_receive_port_setup(&local->dev.sbd,
+		PS3_BINDING_CPU_ANY, &irq);
 	if (res) {
 		pr_err("%s:%u: ps3_sb_event_receive_port_setup failed %d\n",
 		       __func__, __LINE__, res);
 	       goto fail_close_device;
 	}
 
-	spin_lock_init(&dev.lock);
-	rcuwait_init(&dev.wait);
+	spin_lock_init(&local->dev.lock);
+	rcuwait_init(&local->dev.wait);
 
 	res = request_irq(irq, ps3_notification_interrupt, 0,
-			  "ps3_notification", &dev);
+			  "ps3_notification", &local->dev);
 	if (res) {
 		pr_err("%s:%u: request_irq failed %d\n", __func__, __LINE__,
 		       res);
@@ -823,7 +825,7 @@ static int ps3_probe_thread(void *data)
 	notify_cmd->operation_code = 0; /* must be zero */
 	notify_cmd->event_mask = 1UL << notify_region_probe;
 
-	res = ps3_notification_read_write(&dev, lpar, 1);
+	res = ps3_notification_read_write(&local->dev, lpar, 1);
 	if (res)
 		goto fail_free_irq;
 
@@ -834,7 +836,7 @@ static int ps3_probe_thread(void *data)
 
 		memset(notify_event, 0, sizeof(*notify_event));
 
-		res = ps3_notification_read_write(&dev, lpar, 0);
+		res = ps3_notification_read_write(&local->dev, lpar, 0);
 		if (res)
 			break;
 
@@ -845,25 +847,26 @@ static int ps3_probe_thread(void *data)
 			notify_event->dev_port);
 
 		if (notify_event->event_type != notify_region_probe ||
-		    notify_event->bus_id != dev.sbd.bus_id) {
+			notify_event->bus_id != local->dev.sbd.bus_id) {
 			pr_warn("%s:%u: bad notify_event: event %llu, dev_id %llu, dev_type %llu\n",
 				__func__, __LINE__, notify_event->event_type,
 				notify_event->dev_id, notify_event->dev_type);
 			continue;
 		}
 
-		ps3_find_and_add_device(dev.sbd.bus_id, notify_event->dev_id);
+		ps3_find_and_add_device(local->dev.sbd.bus_id,
+			notify_event->dev_id);
 
 	} while (!kthread_should_stop());
 
 fail_free_irq:
-	free_irq(irq, &dev);
+	free_irq(irq, &local->dev);
 fail_sb_event_receive_port_destroy:
-	ps3_sb_event_receive_port_destroy(&dev.sbd, irq);
+	ps3_sb_event_receive_port_destroy(&local->dev.sbd, irq);
 fail_close_device:
-	lv1_close_device(dev.sbd.bus_id, dev.sbd.dev_id);
+	lv1_close_device(local->dev.sbd.bus_id, local->dev.sbd.dev_id);
 fail_free:
-	kfree(buf);
+	kfree(local);
 
 	probe_task = NULL;