media: mediatek: vcodec: Use spinlock for context list protection lock

[ Upstream commit a5844227e0f030d2af2d85d4aed10c5eca6ca176 ]

Previously a mutex was added to protect the encoder and decoder context
lists from unexpected changes originating from the SCP IP block, causing
the context pointer to go invalid, resulting in a NULL pointer
dereference in the IPI handler.

Turns out on the MT8173, the VPU IPI handler is called from hard IRQ
context. This causes a big warning from the scheduler. This was first
reported downstream on the ChromeOS kernels, but is also reproducible
on mainline using Fluster with the FFmpeg v4l2m2m decoders. Even though
the actual capture format is not supported, the affected code paths
are triggered.

Since this lock just protects the context list and operations on it are
very fast, it should be OK to switch to a spinlock.

Fixes: 6467cda18c9f ("media: mediatek: vcodec: adding lock to protect decoder context list")
Fixes: afaaf3a0f647 ("media: mediatek: vcodec: adding lock to protect encoder context list")
Cc: Yunfei Dong <yunfei.dong@mediatek.com>
Cc: stable@vger.kernel.org
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Fei Shao <fshao@chromium.org>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
[ adapted file_to_dec_ctx() and file_to_enc_ctx() helper calls to equivalent fh_to_dec_ctx(file->private_data) and fh_to_enc_ctx(file->private_data) pattern ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions