Hi John,

On 01/22/2016 02:27 AM, John Ogness wrote:

serial8250_rx_chars() must be called from interrupt context and with
the port lock held. The port lock is released temporarily within that
function to call tty_flip_buffer_push(). However, there may be other
drivers that need to synchronize the tty_flip_buffer_push() call within
serial8250_rx_chars() with other contexts. Since the port lock cannot
be used for this synchronization, an optional spinlock argument is added.
If non-NULL, this will be locked during the tty_flip_buffer_push() call.

I removed the port lock drop-claim in serial8250_rx_chars in patch
"serial: 8250: Remove low_latency workaround" (Greg has this patch in his
inbox but not in next because of the merge window).

IOW, you can drop this patch.

Regards,
Peter Hurley