From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752381Ab2H3NgY (ORCPT ); Thu, 30 Aug 2012 09:36:24 -0400 Received: from mail-bk0-f46.google.com ([209.85.214.46]:58682 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752021Ab2H3NgX (ORCPT ); Thu, 30 Aug 2012 09:36:23 -0400 Message-ID: <503F6C52.6030100@suse.cz> Date: Thu, 30 Aug 2012 15:36:18 +0200 From: Jiri Slaby User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120815 Thunderbird/15.0 MIME-Version: 1.0 To: Baodong Chen CC: gregkh@linuxfoundation.org, davem@davemloft.net, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] staging:fixed code to fit tty_driver's kref filed fixed code to fit tty_driver's kref filed for drivers/staging/net/pc300_tty.c References: <1346074458-2659-1-git-send-email-chenbdchenbd@gmail.com> In-Reply-To: <1346074458-2659-1-git-send-email-chenbdchenbd@gmail.com> X-Enigmail-Version: 1.4.4 Content-Type: text/plain; charset=ISO-8859-2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/27/2012 03:34 PM, Baodong Chen wrote: Sorry, I do not get this change. You should not touch tty_driver.kref at all. And what is the patch good for? > Signed-off-by: Baodong Chen > --- > drivers/staging/net/pc300_tty.c | 55 ++++++++++++++++++++++----------------- > 1 files changed, 31 insertions(+), 24 deletions(-) > > diff --git a/drivers/staging/net/pc300_tty.c b/drivers/staging/net/pc300_tty.c > index 4709f42..91ada93 100644 > --- a/drivers/staging/net/pc300_tty.c > +++ b/drivers/staging/net/pc300_tty.c > @@ -46,6 +46,8 @@ > #include > #include > #include > +#include > + > /* TTY includes */ > #include > #include > @@ -134,12 +136,26 @@ static void cpc_tty_signal_on(pc300dev_t *pc300dev, unsigned char); > static int pc300_tiocmset(struct tty_struct *, unsigned int, unsigned int); > static int pc300_tiocmget(struct tty_struct *); > > +static void cpc_tty_do_unreg_driver(struct kref *ref); > + > /* functions called by PC300 driver */ > void cpc_tty_init(pc300dev_t *dev); > void cpc_tty_unregister_service(pc300dev_t *pc300dev); > void cpc_tty_receive(pc300dev_t *pc300dev); > void cpc_tty_trigger_poll(pc300dev_t *pc300dev); > > +static void cpc_tty_do_unreg_driver(struct kref *ref) > +{ > + struct tty_driver *drv = container_of(ref, struct tty_driver, kref); > + int ret; > + > + cpc_tty_unreg_flag = 0; > + > + res = tty_unregister_driver(drv); > + if (res) > + CPC_TTY_DBG("unregister the tty driver error=%d\n", res); > +} > + > /* > * PC300 TTY clear "signal" > */ > @@ -239,6 +255,8 @@ void cpc_tty_init(pc300dev_t *pc300dev) > /* interface routines from the upper tty layer to the tty driver */ > tty_set_operations(&serial_drv, &pc300_ops); > > + kref_init(&serial_drv.kref); > + > /* register the TTY driver */ > if (tty_register_driver(&serial_drv)) { > printk("%s-tty: Failed to register serial driver! ", > @@ -408,13 +426,9 @@ static void cpc_tty_close(struct tty_struct *tty, struct file *flip) > > CPC_TTY_DBG("%s: TTY closed\n",cpc_tty->name); > > - if (!serial_drv.refcount && cpc_tty_unreg_flag) { > - cpc_tty_unreg_flag = 0; > - CPC_TTY_DBG("%s: unregister the tty driver\n", cpc_tty->name); > - if ((res=tty_unregister_driver(&serial_drv))) { > - CPC_TTY_DBG("%s: ERROR ->unregister the tty driver error=%d\n", > - cpc_tty->name,res); > - } > + if (cpc_tty_unreg_flag) { > + CPC_TTY_DBG("%s: checking unregister the tty driver...\n", cpc_tty->name); > + kref_put(&serial_drv.kref, cpc_tty_do_unreg_driver); > } > return; > } > @@ -644,13 +658,9 @@ static void cpc_tty_hangup(struct tty_struct *tty) > CPC_TTY_DBG("%s: TTY is not opened\n",cpc_tty->name); > return ; > } > - if (!serial_drv.refcount && cpc_tty_unreg_flag) { > - cpc_tty_unreg_flag = 0; > - CPC_TTY_DBG("%s: unregister the tty driver\n", cpc_tty->name); > - if ((res=tty_unregister_driver(&serial_drv))) { > - CPC_TTY_DBG("%s: ERROR ->unregister the tty driver error=%d\n", > - cpc_tty->name,res); > - } > + if (cpc_tty_unreg_flag) { > + CPC_TTY_DBG("%s: checking unregister the tty driver...\n", cpc_tty->name); > + kref_put(&serial_drv.kref, cpc_tty_do_unreg_driver); > } > cpc_tty_signal_off(cpc_tty->pc300dev, CTL_DTR); > } > @@ -1043,19 +1053,16 @@ void cpc_tty_unregister_service(pc300dev_t *pc300dev) > return; > } > > - if (--cpc_tty_cnt == 0) { > - if (serial_drv.refcount) { > - CPC_TTY_DBG("%s: unregister is not possible, refcount=%d", > - cpc_tty->name, serial_drv.refcount); > + if (--cpc_tty_cnt == 0) { > + CPC_TTY_DBG("%s: checking unregister the tty driver...\n", > + cpc_tty->name); > + res = kref_put(&serial_drv.kref, cpc_tty_do_unreg_driver); > + if (0 == res) { > + CPC_TTY_DBG("%s: unregister is not possible\n", > + cpc_tty->name); > cpc_tty_cnt++; > cpc_tty_unreg_flag = 1; > return; > - } else { > - CPC_TTY_DBG("%s: unregister the tty driver\n", cpc_tty->name); > - if ((res=tty_unregister_driver(&serial_drv))) { > - CPC_TTY_DBG("%s: ERROR ->unregister the tty driver error=%d\n", > - cpc_tty->name,res); > - } > } > } > CPC_TTY_LOCK(pc300dev->chan->card,flags); > -- js suse labs