From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anand Moon Subject: Re: [PATCH] serial: samsung: fix the inconsistency in spinlock Date: Fri, 19 Feb 2016 00:44:53 +0530 Message-ID: References: <1455817202-3005-1-git-send-email-linux.amoon@gmail.com> <56C603E9.9050307@hurleysoftware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <56C603E9.9050307@hurleysoftware.com> Sender: linux-samsung-soc-owner@vger.kernel.org To: Peter Hurley Cc: Greg Kroah-Hartman , Jiri Slaby , linux-serial@vger.kernel.org, "linux-samsung-soc@vger.kernel.org" , Linux Kernel List-Id: linux-serial@vger.kernel.org Hi Peter, On 18 February 2016 at 23:18, Peter Hurley wrote: > Hi Anand, > > On 02/18/2016 09:40 AM, Anand Moon wrote: >> From: Anand Moon >> >> changes fix the correct order of the spin_lock_irqrestore/save. >> >> Signed-off-by: Anand Moon >> --- >> drivers/tty/serial/samsung.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c >> index d72cd73..96fe14d 100644 >> --- a/drivers/tty/serial/samsung.c >> +++ b/drivers/tty/serial/samsung.c >> @@ -759,9 +759,9 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id) >> } >> >> if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) { >> - spin_unlock(&port->lock); >> + spin_unlock_irqrestore(&port->lock, flags); >> uart_write_wakeup(port); >> - spin_lock(&port->lock); >> + spin_lock_irqsave(&port->lock, flags); > > This driver shouldn't be dropping the spin lock at for write wakeup. > If this is causing lock-ups in a line discipline, the line discipline > needs fixed. > Thanks for pointing out. Their is no lock up, just the inconstancy of the spin_lock. Then I will resend this patch dropping the spin_unlock/spin_lock around uart_write_wakeup. Is that ok with you. > Regards, > Peter Hurley > > >> } >> >> if (uart_circ_empty(xmit)) >> > Best Regards -Anand Moon