[v4,12/15] drivers/firmware/sdei: Remove _sdei_event_register()
diff mbox series

Message ID 20200730014531.310465-13-gshan@redhat.com
State New
Headers show
Series
  • Refactor SDEI client driver
Related show

Commit Message

Gavin Shan July 30, 2020, 1:45 a.m. UTC
The function _sdei_event_register() is called by sdei_event_register()
and sdei_device_thaw() as the following functional call chain shows.
_sdei_event_register() covers the shared and private events, but
sdei_device_thaw() only covers the shared events. So the logic to
cover the private events in _sdei_event_register() isn't needed by
sdei_device_thaw().

Similarly, sdei_reregister_event_llocked() covers the shared and
private events in the regard of reenablement. The logic to cover
the private events isn't needed by sdei_device_thaw() either.

   sdei_event_register          sdei_device_thaw
      _sdei_event_register         sdei_reregister_shared
                                      sdei_reregister_event_llocked
                                         _sdei_event_register

This removes _sdei_event_register() and sdei_reregister_event_llocked().
Their logic is moved to sdei_event_register() and sdei_reregister_shared().
This shouldn't cause any logicial changes.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/firmware/arm_sdei.c | 77 ++++++++++++++-----------------------
 1 file changed, 28 insertions(+), 49 deletions(-)

Comments

James Morse Sept. 18, 2020, 4:14 p.m. UTC | #1
Hi Gavin,

On 30/07/2020 02:45, Gavin Shan wrote:
> The function _sdei_event_register() is called by sdei_event_register()
> and sdei_device_thaw() as the following functional call chain shows.
> _sdei_event_register() covers the shared and private events, but
> sdei_device_thaw() only covers the shared events. So the logic to
> cover the private events in _sdei_event_register() isn't needed by
> sdei_device_thaw().
> 
> Similarly, sdei_reregister_event_llocked() covers the shared and
> private events in the regard of reenablement. The logic to cover
> the private events isn't needed by sdei_device_thaw() either.

These were added for code-reuse instead of duplication, but from the diff-stat it looks
like it cut-in too high up and would have been simpler not to. (I remember cpuhp being a
nightmare)


>    sdei_event_register          sdei_device_thaw
>       _sdei_event_register         sdei_reregister_shared
>                                       sdei_reregister_event_llocked
>                                          _sdei_event_register
> 
> This removes _sdei_event_register() and sdei_reregister_event_llocked().
> Their logic is moved to sdei_event_register() and sdei_reregister_shared().
> This shouldn't cause any logicial changes.

(logical)


>  drivers/firmware/arm_sdei.c | 77 ++++++++++++++-----------------------
>  1 file changed, 28 insertions(+), 49 deletions(-)

>  static int sdei_reregister_shared(void)
>  {
>  	int err = 0;
> @@ -674,9 +638,24 @@ static int sdei_reregister_shared(void)
>  			continue;
>  
>  		if (event->reregister) {
> -			err = sdei_reregister_event_llocked(event);
> -			if (err)
> +			err = sdei_api_event_register(event->event_num,
> +					sdei_entry_point, event->registered,
> +					SDEI_EVENT_REGISTER_RM_ANY, 0);
> +			if (err) {
> +				sdei_event_destroy_llocked(event);

> +				pr_err("Failed to re-register event %u\n",
> +				       event->event_num);

sdei_event_destroy_llocked() just free()'d event. You need to print the error first.


>  				break;
> +			}
> +		}
> +
> +		if (event->reenable) {
> +			err = sdei_api_event_enable(event->event_num);
> +			if (err) {
> +				pr_err("Failed to re-enable event %u\n",
> +				       event->event_num);
> +				break;
> +			}
>  		}
>  	}
>  	spin_unlock(&sdei_list_lock);


With the use-after-free fixed:
Reviewed-by: James Morse <james.morse@arm.com>


Thanks,

James

Patch
diff mbox series

diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
index 7f4309039513..749f1619e652 100644
--- a/drivers/firmware/arm_sdei.c
+++ b/drivers/firmware/arm_sdei.c
@@ -577,25 +577,6 @@  static void _local_event_register(void *data)
 	sdei_cross_call_return(arg, err);
 }
 
-static int _sdei_event_register(struct sdei_event *event)
-{
-	int err;
-
-	lockdep_assert_held(&sdei_events_lock);
-
-	if (event->type == SDEI_EVENT_TYPE_SHARED)
-		return sdei_api_event_register(event->event_num,
-					       sdei_entry_point,
-					       event->registered,
-					       SDEI_EVENT_REGISTER_RM_ANY, 0);
-
-	err = sdei_do_cross_call(_local_event_register, event);
-	if (err)
-		sdei_do_cross_call(_local_event_unregister, event);
-
-	return err;
-}
-
 int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg)
 {
 	int err;
@@ -618,7 +599,17 @@  int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg)
 	}
 
 	cpus_read_lock();
-	err = _sdei_event_register(event);
+	if (event->type == SDEI_EVENT_TYPE_SHARED) {
+		err = sdei_api_event_register(event->event_num,
+					      sdei_entry_point,
+					      event->registered,
+					      SDEI_EVENT_REGISTER_RM_ANY, 0);
+	} else {
+		err = sdei_do_cross_call(_local_event_register, event);
+		if (err)
+			sdei_do_cross_call(_local_event_unregister, event);
+	}
+
 	if (err) {
 		sdei_event_destroy(event);
 		pr_warn("Failed to register event %u: %d\n", event_num, err);
@@ -635,33 +626,6 @@  int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg)
 	return err;
 }
 
-static int sdei_reregister_event_llocked(struct sdei_event *event)
-{
-	int err;
-
-	lockdep_assert_held(&sdei_events_lock);
-	lockdep_assert_held(&sdei_list_lock);
-
-	err = _sdei_event_register(event);
-	if (err) {
-		pr_err("Failed to re-register event %u\n", event->event_num);
-		sdei_event_destroy_llocked(event);
-		return err;
-	}
-
-	if (event->reenable) {
-		if (event->type == SDEI_EVENT_TYPE_SHARED)
-			err = sdei_api_event_enable(event->event_num);
-		else
-			err = sdei_do_cross_call(_local_event_enable, event);
-	}
-
-	if (err)
-		pr_err("Failed to re-enable event %u\n", event->event_num);
-
-	return err;
-}
-
 static int sdei_reregister_shared(void)
 {
 	int err = 0;
@@ -674,9 +638,24 @@  static int sdei_reregister_shared(void)
 			continue;
 
 		if (event->reregister) {
-			err = sdei_reregister_event_llocked(event);
-			if (err)
+			err = sdei_api_event_register(event->event_num,
+					sdei_entry_point, event->registered,
+					SDEI_EVENT_REGISTER_RM_ANY, 0);
+			if (err) {
+				sdei_event_destroy_llocked(event);
+				pr_err("Failed to re-register event %u\n",
+				       event->event_num);
 				break;
+			}
+		}
+
+		if (event->reenable) {
+			err = sdei_api_event_enable(event->event_num);
+			if (err) {
+				pr_err("Failed to re-enable event %u\n",
+				       event->event_num);
+				break;
+			}
 		}
 	}
 	spin_unlock(&sdei_list_lock);