[PATCH] drm/xe/display: check for error on drmm_mutex_init

[Lucas De Marchi]

On Tue, Mar 19, 2024 at 08:33:41AM +0530, Arun R Murthy wrote:
>Check return value for drmm_mutex_init as it can fail and return on
>failure.
>
>Signed-off-by: Arun R Murthy <arun.r.murthy at intel.com>
>---
> drivers/gpu/drm/xe/display/xe_display.c | 24 ++++++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>
>diff --git a/drivers/gpu/drm/xe/display/xe_display.c b/drivers/gpu/drm/xe/display/xe_display.c
>index e4db069f0db3..c59fa832758d 100644
>--- a/drivers/gpu/drm/xe/display/xe_display.c
>+++ b/drivers/gpu/drm/xe/display/xe_display.c
>@@ -107,12 +107,24 @@ int xe_display_create(struct xe_device *xe)
>
> 	xe->display.hotplug.dp_wq = alloc_ordered_workqueue("xe-dp", 0);
>
>-	drmm_mutex_init(&xe->drm, &xe->sb_lock);
>-	drmm_mutex_init(&xe->drm, &xe->display.backlight.lock);
>-	drmm_mutex_init(&xe->drm, &xe->display.audio.mutex);
>-	drmm_mutex_init(&xe->drm, &xe->display.wm.wm_mutex);
>-	drmm_mutex_init(&xe->drm, &xe->display.pps.mutex);
>-	drmm_mutex_init(&xe->drm, &xe->display.hdcp.hdcp_mutex);
>+	err = drmm_mutex_init(&xe->drm, &xe->sb_lock);
>+	if (err)
>+		return err;
>+	err = drmm_mutex_init(&xe->drm, &xe->display.backlight.lock);
>+	if (err)
>+		return err;
>+	err = drmm_mutex_init(&xe->drm, &xe->display.audio.mutex);
>+	if (err)
>+		return err;
>+	err = drmm_mutex_init(&xe->drm, &xe->display.wm.wm_mutex);
>+	if (err)
>+		return err;
>+	err = drmm_mutex_init(&xe->drm, &xe->display.pps.mutex);
>+	if (err)
>+		return err;
>+	err = drmm_mutex_init(&xe->drm, &xe->display.hdcp.hdcp_mutex);
>+	if (err)
>+		return err;


humn... but not very pretty. What about?

	if ((err = drmm_mutex_init(&xe->drm, &xe->sb_lock)) ||
	    (err = drmm_mutex_init(&xe->drm, &xe->display.backlight.lock)) ||
	    (err = ...))
		return err;

I think there are few places in life for assignment + check in single
statement, but IMO this is one of them where the alternative is uglier
and more error prone.

thoughts?

Lucas De Marchi

> 	xe->enabled_irq_mask = ~0;
>
> 	err = drmm_add_action_or_reset(&xe->drm, display_destroy, NULL);
>-- 
>2.25.1
>