tty: serial: 8250: omap: synchronize rx_running

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The rx_running flag should show if DMA is currently active. However
there is a window between when the flag is set/cleared and when
the DMA is started/stopped. Because the flag is queried from both
hard and soft irq contexts, the driver can make incorrect
decisions and do things like start a DMA transfer using a buffer
that is already setup to be used for a DMA transfer.

This patch adds a spinlock to synchronize the rx_running flag and
close the above mentioned window.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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John Ogness 2015-04-27 13:52:33 +02:00 • committed by Greg Kroah-Hartman

parent 02ec6041a8

commit eda0cd3546

1 changed files with 49 additions and 16 deletions

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drivers/tty/serial/8250/8250_omap.c

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