The patch titled blackfin serial driver: use barrier instead of cpu_relax for Blackfin SMP like patch has been added to the -mm tree. Its filename is blackfin-serial-driver-use-barrier-instead-of-cpu_relax-for-blackfin-smp-like-patch.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: blackfin serial driver: use barrier instead of cpu_relax for Blackfin SMP like patch From: Graf Yang <graf.yang@xxxxxxxxxx> We are making a SMP like patch to blackfin, cpu_relax() is replaced by a data cache flush function which will count it to a per-cpu counter. If this serial function is called too early, the per-cpu data area have not been initialized, this call will cause crash. So we'd like to use barrier() instead of cpu_relax(). Signed-off-by: Graf Yang <graf.yang@xxxxxxxxxx> Signed-off-by: Bryan Wu <cooloney@xxxxxxxxxx> Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/serial/bfin_5xx.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff -puN drivers/serial/bfin_5xx.c~blackfin-serial-driver-use-barrier-instead-of-cpu_relax-for-blackfin-smp-like-patch drivers/serial/bfin_5xx.c --- a/drivers/serial/bfin_5xx.c~blackfin-serial-driver-use-barrier-instead-of-cpu_relax-for-blackfin-smp-like-patch +++ a/drivers/serial/bfin_5xx.c @@ -1129,7 +1129,8 @@ static __init void early_serial_putc(str struct bfin_serial_port *uart = (struct bfin_serial_port *)port; while ((!(UART_GET_LSR(uart) & THRE)) && --timeout) - cpu_relax(); + barrier(); + UART_PUT_CHAR(uart, ch); } _ Patches currently in -mm which might be from graf.yang@xxxxxxxxxx are linux-next.patch mtd-cfi-fix-bug-bonnie-error-on-bf548-nor-flash.patch blackfin-serial-driver-add-a-debug-function-to-serial-driver.patch blackfin-serial-driver-use-barrier-instead-of-cpu_relax-for-blackfin-smp-like-patch.patch blackfin-serial-driver-fix-bug-up-arrow-key-works-abnormal-for-bf561-ezkit-board.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html