tree 9559f3a5432e0abde1e3257fc36415f3b4b3d67d
parent 0907c1004f9bbe5bda0d3d2be46520b729de5c1d
author Geert Uytterhoeven <geert+renesas@glider.be> 1440180170 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1443976428 +0100

serial: sh-sci: Fix race condition between RX worker and cleanup

During serial port shutdown, the DMA receive worker function may still
be called after the receive DMA cleanup function has been called.
Fix this race condition between work_fn_rx() and sci_rx_dma_release() by
acquiring the port's spinlock in sci_rx_dma_release().
This requires releasing the spinlock in work_fn_rx() before calling (any
function that may call) sci_rx_dma_release().

Terminate all active receive DMA descriptors to release them, and to
make sure no more completions come in.

Do the same in sci_tx_dma_release() for symmetry, although the serial
upper layer will no longer submit more data at this point of time.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>