[ Upstream commit 80fc671bcc ]
The uacce driver must deal with a possible removal of the parent device
or parent driver module rmmod at any time.
Although uacce_remove(), called on device removal and on driver unbind,
prevents future use of the uacce fops by removing the cdev, fops that
were called before that point may still be running.
Serialize uacce_fops_open() and uacce_remove() with uacce->mutex.
Serialize other fops against uacce_remove() with q->mutex.
Since we need to protect uacce_fops_poll() which gets called on the fast
path, replace uacce->queues_lock with q->mutex to improve scalability.
The other fops are only used during setup.
uacce_queue_is_valid(), checked under q->mutex or uacce->mutex, denotes
whether uacce_remove() has disabled all queues. If that is the case,
don't go any further since the parent device is being removed and
uacce->ops should not be called anymore.
Reported-by: Yang Shen <shenyang39@huawei.com>
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20220701034843.7502-1-zhangfei.gao@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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