On Thu, Mar 21, 2024 at 05:04:51AM +0000, Murthy, Arun R wrote:
-----Original Message-----
From: De Marchi, Lucas <lucas.demarchi@xxxxxxxxx>
Sent: Wednesday, March 20, 2024 6:06 AM
To: Murthy, Arun R <arun.r.murthy@xxxxxxxxx>
Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; intel-xe@xxxxxxxxxxxxxxxxxxxxx
Subject: Re: [PATCH] drm/xe/display: check for error on drmm_mutex_init
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@xxxxxxxxx>
>---
> 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?
We should not proceed with the remaining mutex_init in case of failures. As an alternative we can have
with the code above, we are not proceeding with the other drmm_mutex_init() initializations.
foo() || bar() doesn't execute bar() if foo() returned != 0.
Lucas De Marchi
drmm_mutex_init(var1) ? (drmm_mutex_init(var2) ? drmm_mutex_init(var3) : return ret) : return ret;
With the existing one traversing the code is more easier, these optimization might make the code look complex.
Thanks and Regards,
Arun R Murthy
--------------------
Lucas De Marchi
> xe->enabled_irq_mask = ~0;
>
> err = drmm_add_action_or_reset(&xe->drm, display_destroy, NULL);
>--
>2.25.1
>
