serial: ifx6x60: add_timer is not safe in the mrdy_assert function
authorJun Chen <jun.d.chen@intel.com>
Mon, 22 Oct 2012 14:23:07 +0000 (10:23 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 25 Oct 2012 18:29:58 +0000 (11:29 -0700)
commitc73ba2ae43fd4d69589caeecc5260a41be87b759
tree1cb25c6cf3d0eb3010e8e24c1e1531ad4569431e
parent319fb0d21907f771d8ccdb6177fb2fcafabc6ab4
serial: ifx6x60: add_timer is not safe in the mrdy_assert function

This patch make use of mod_timer instead of add_timer in the mrdy_assert function.
Because the srdy interrupter can go high when we are running function mrdy_assert and mrdy_assert
can be called by multi-entry. In our medfield platform, spi stress test can encounter this
error logs triggered by the BUG_ON of add_timer function.This patch had been tested on
our medfield platform.

the scenario:
      CPU0 CPU1
mrdy_assert
set_bit(IFX_SPI_STATE_TIMER_PENDING)
ifx_spi_handle_srdy
...
clear_bit(IFX_SPI_STATE_TIMER_PENDING)
...
mrdy_assert
set_bit(IFX_SPI_STATE_TIMER_PENDING)
...
add_timer
...
add_timer

Cc: liu chuansheng <chuansheng.liu@intel.com>
Cc: Bi Chao <chao.bi@intel.com>
Signed-off-by: Chen Jun <jun.d.chen@intel.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/tty/serial/ifx6x60.c