FAILED: patch "[PATCH] drm/tegra: Fix vmapping of prime buffers" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c7860cbee9989882d2908682526a5ef617523cfe Mon Sep 17 00:00:00 2001
From: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Date: Wed, 29 Jun 2022 01:42:39 +0300
Subject: [PATCH] drm/tegra: Fix vmapping of prime buffers

The code assumes that Tegra GEM is permanently vmapped, which is not
true for the scattered buffers. After converting Tegra video decoder
driver to V4L API, we're now getting a BUG_ON from dma-buf core on playing
video using libvdpau-tegra on T30+ because tegra_gem_prime_vmap() sets
vaddr to NULL. Older pre-V4L video decoder driver wasn't vmapping dma-bufs.
Fix it by actually vmapping the exported GEMs.

Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
index 7c7dd84e6db8..81991090adcc 100644
--- a/drivers/gpu/drm/tegra/gem.c
+++ b/drivers/gpu/drm/tegra/gem.c
@@ -704,14 +704,23 @@ static int tegra_gem_prime_vmap(struct dma_buf *buf, struct iosys_map *map)
 {
 	struct drm_gem_object *gem = buf->priv;
 	struct tegra_bo *bo = to_tegra_bo(gem);
+	void *vaddr;
 
-	iosys_map_set_vaddr(map, bo->vaddr);
+	vaddr = tegra_bo_mmap(&bo->base);
+	if (IS_ERR(vaddr))
+		return PTR_ERR(vaddr);
+
+	iosys_map_set_vaddr(map, vaddr);
 
 	return 0;
 }
 
 static void tegra_gem_prime_vunmap(struct dma_buf *buf, struct iosys_map *map)
 {
+	struct drm_gem_object *gem = buf->priv;
+	struct tegra_bo *bo = to_tegra_bo(gem);
+
+	tegra_bo_munmap(&bo->base, map->vaddr);
 }
 
 static const struct dma_buf_ops tegra_gem_prime_dmabuf_ops = {