[PATCH] drm/mediatek: Correctly free sg_table in gem prime vmap

[AngeloGioacchino Del Regno]

Il 02/10/23 11:20, Chen-Yu Tsai ha scritto:
> The MediaTek DRM driver implements GEM PRIME vmap by fetching the
> sg_table for the object, iterating through the pages, and then
> vmapping them. In essence, unlike the GEM DMA helpers which vmap
> when the object is first created or imported, the MediaTek version
> does it on request.
> 
> Unfortunately, the code never correctly frees the sg_table contents.
> This results in a kernel memory leak. On a Hayato device with a text
> console on the internal display, this results in the system running
> out of memory in a few days from all the console screen cursor updates.
> 
> Add sg_free_table() to correctly free the contents of the sg_table. This
> was missing despite explicitly required by mtk_gem_prime_get_sg_table().
> 
> Fixes: 3df64d7b0a4f ("drm/mediatek: Implement gem prime vmap/vunmap function")
> Cc: <stable at vger.kernel.org>
> Signed-off-by: Chen-Yu Tsai <wenst at chromium.org>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>