linux-kernel - [PATCH 1/7] drm: Fix drm_fixp2int

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240306-louis-vkms-conv-v1-1-5bfe7d129fdd@riseup.net>
Date: Wed, 06 Mar 2024 17:03:08 -0300
From: Arthur Grillo <arthurgrillo@...eup.net>
To: Rodrigo Siqueira <rodrigosiqueiramelo@...il.com>, 
 Melissa Wen <melissa.srw@...il.com>, 
 Maíra Canal <mairacanal@...eup.net>, 
 Haneen Mohammed <hamohammed.sa@...il.com>, Daniel Vetter <daniel@...ll.ch>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, arthurgrillo@...eup.net, 
 Jonathan Corbet <corbet@....net>, pekka.paalanen@...oniitty.fi, 
 Louis Chauvet <louis.chauvet@...tlin.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 jeremie.dautheribes@...tlin.com, miquel.raynal@...tlin.com, 
 thomas.petazzoni@...tlin.com, seanpaul@...gle.com, marcheu@...gle.com, 
 nicolejadeyee@...gle.com, Pekka Paalanen <pekka.paalanen@...labora.com>
Subject: [PATCH 1/7] drm: Fix drm_fixp2int_round() making it add 0.5

As well noted by Pekka[1], the rounding of drm_fixp2int_round is wrong.
To round a number, you need to add 0.5 to the number and floor that,
drm_fixp2int_round() is adding 0.0000076. Make it add 0.5.

[1]: https://lore.kernel.org/all/20240301135327.22efe0dd.pekka.paalanen@collabora.com/

Suggested-by: Pekka Paalanen <pekka.paalanen@...labora.com>
Signed-off-by: Arthur Grillo <arthurgrillo@...eup.net>
---
 include/drm/drm_fixed.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h
index 0c9f917a4d4b..de3a79909ac9 100644
--- a/include/drm/drm_fixed.h
+++ b/include/drm/drm_fixed.h
@@ -90,7 +90,7 @@ static inline int drm_fixp2int(s64 a)
 
 static inline int drm_fixp2int_round(s64 a)
 {
-	return drm_fixp2int(a + (1 << (DRM_FIXED_POINT_HALF - 1)));
+	return drm_fixp2int(a + DRM_FIXED_ONE / 2);
 }
 
 static inline int drm_fixp2int_ceil(s64 a)

-- 
2.43.0