commit 2f7caf6b02 upstream.
If we ran out of DMA pool buffers, we get into the unmap
code path with a NULL before. Deal with this by checking
the virtual mapping is not NULL.
Cc: stable@vger.kernel.org
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>