Hi,Alan Thank for your question, I will update this patch in other email. -----Original Message----- From: Alan Cox [mailto:alan@xxxxxxxxxxxxxxxxxxx] Sent: Tuesday, November 06, 2012 5:47 PM To: Chen, Jun D Cc: Alan Cox; serial; Gorby, Russ; Bi, Chao Subject: Re: [PATCH] serial: ifx6x60: ifx_spi_write don't need to do mrdy_assert when fifo is not empty. On Tue, 06 Nov 2012 04:28:54 -0500 Jun Chen <jun.d.chen@xxxxxxxxx> wrote: > > This patch check whether the kfifo lenth equal to the count of write > data.If condition is true,ifx_spi_write need to trigger one > mrdy_assert. If condition is false,the mrdy_assert will be triggered by the next ifx_spi_io. > Cc: Bi Chao <chao.bi@xxxxxxxxx> > Signed-off-by: Chen Jun <jun.d.chen@xxxxxxxxx> > --- > drivers/tty/serial/ifx6x60.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/drivers/tty/serial/ifx6x60.c > b/drivers/tty/serial/ifx6x60.c index ac718e1..b52ef8d 100644 > --- a/drivers/tty/serial/ifx6x60.c > +++ b/drivers/tty/serial/ifx6x60.c > @@ -522,7 +522,8 @@ static int ifx_spi_write(struct tty_struct *tty, const unsigned char *buf, > unsigned char *tmp_buf = (unsigned char *)buf; > int tx_count = kfifo_in_locked(&ifx_dev->tx_fifo, tmp_buf, count, > &ifx_dev->fifo_lock); > - mrdy_assert(ifx_dev); > + if (kfifo_len(&ifx_dev->tx_fifo) == count) > + mrdy_assert(ifx_dev); > return tx_count; I'm not convinced this is safe. What stops the sending task from emptying data out of the fifo between the kfifo_in_locked and the kfifo_len check ? Can't you just check tx_count ? Alan -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
