linux-kernel - [PATCH v2 5/5] drm/repaper: Reduce temporary buffer size in repaper_fb

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Date:   Thu, 17 Mar 2022 09:18:30 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Javier Martinez Canillas <javierm@...hat.com>,
        Noralf Trønnes <noralf@...nnes.org>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Geert Uytterhoeven <geert@...ux-m68k.org>
Subject: [PATCH v2 5/5] drm/repaper: Reduce temporary buffer size in repaper_fb_dirty()

As the temporary buffer is no longer used to store 8-bit grayscale data,
its size can be reduced to the size needed to store the monochrome
bitmap data.

Fixes: 24c6bedefbe71de9 ("drm/repaper: Use format helper for xrgb8888 to monochrome conversion")
Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
Reviewed-by: Javier Martinez Canillas <javierm@...hat.com>
---
v2:
  - Add Reviewed-by.

Untested due to lack of hardware.

I replaced kmalloc_array() by kmalloc() to match size calculations in
other locations in this driver.  There is no point in handling a
possible multiplication overflow only here.
---
 drivers/gpu/drm/tiny/repaper.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tiny/repaper.c b/drivers/gpu/drm/tiny/repaper.c
index a096fb8b83e99dc8..7738b87f370ad147 100644
--- a/drivers/gpu/drm/tiny/repaper.c
+++ b/drivers/gpu/drm/tiny/repaper.c
@@ -530,7 +530,7 @@ static int repaper_fb_dirty(struct drm_framebuffer *fb)
 	DRM_DEBUG("Flushing [FB:%d] st=%ums\n", fb->base.id,
 		  epd->factored_stage_time);
 
-	buf = kmalloc_array(fb->width, fb->height, GFP_KERNEL);
+	buf = kmalloc(fb->width * fb->height / 8, GFP_KERNEL);
 	if (!buf) {
 		ret = -ENOMEM;
 		goto out_exit;
-- 
2.25.1