On Tue, Jan 13, 2015 at 05:07:08PM +0100, Michael Doswald wrote: > Under pressure, the imx.c device driver may transfer the same data multiple > times. > > Reason: > Function imx_dma_tx checks for an active DMA transfer by calling > dmaengine_tx_status. The return value may indicate that no transfer is > running while the dma_tx_callback function is still being executed. In > this case the xmit->tail pointer may not be updated to the correct value > when imx_dma_tx initiates a new DMA transfer, which will result in a DMA > transfer with the same base address as the previous one. > > Patch: > Use existing dma_is_txing variable to guard DMA transfer initiation instead > of dmaengine_tx_status. Clear dma_is_txing at the end of the DMA callback > function therefore extending the critical section where the port lock is > held. Critical section extension is in line with the callback function > of other drivers, e.g. serial-tegra.c (tegra_uart_tx_dma_complete). > > > Signed-off-by: Michael Doswald <michael.dosw...@gmx.net> > --- > drivers/tty/serial/imx.c | 11 ++++------- > 1 file changed, 4 insertions(+), 7 deletions(-)
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