[Why]
If flr_work takes read_lock, then other threads who takes
read_lock can access hardware when host is doing vf flr.
[How]
flr_work should take write_lock to avoid this case.
Signed-off-by: Jingwen Chen <Jingwen.Chen2@amd.com>
Reviewed-by: Monk Liu <monk.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
         * otherwise the mailbox msg will be ruined/reseted by
         * the VF FLR.
         */
-       if (!down_read_trylock(&adev->reset_sem))
+       if (!down_write_trylock(&adev->reset_sem))
                return;
 
        amdgpu_virt_fini_data_exchange(adev);
 
 flr_done:
        atomic_set(&adev->in_gpu_reset, 0);
-       up_read(&adev->reset_sem);
+       up_write(&adev->reset_sem);
 
        /* Trigger recovery for world switch failure if no TDR */
        if (amdgpu_device_should_recover_gpu(adev)
 
         * otherwise the mailbox msg will be ruined/reseted by
         * the VF FLR.
         */
-       if (!down_read_trylock(&adev->reset_sem))
+       if (!down_write_trylock(&adev->reset_sem))
                return;
 
        amdgpu_virt_fini_data_exchange(adev);
 
 flr_done:
        atomic_set(&adev->in_gpu_reset, 0);
-       up_read(&adev->reset_sem);
+       up_write(&adev->reset_sem);
 
        /* Trigger recovery for world switch failure if no TDR */
        if (amdgpu_device_should_recover_gpu(adev)