Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754440AbbGXSR7 (ORCPT ); Fri, 24 Jul 2015 14:17:59 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:53192 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752391AbbGXSR5 (ORCPT ); Fri, 24 Jul 2015 14:17:57 -0400 Date: Fri, 24 Jul 2015 11:17:55 -0700 From: Greg Kroah-Hartman To: Petr Tesarik Cc: Johan Hovold , "open list:USB SERIAL SUBSYSTEM" , open list , Petr Tesarik Subject: Re: [PATCH 4/4] cp210x: Expose the part number in sysfs Message-ID: <20150724181755.GA9835@kroah.com> References: <1437720491-28702-1-git-send-email-ptesarik@suse.com> <1437720491-28702-5-git-send-email-ptesarik@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1437720491-28702-5-git-send-email-ptesarik@suse.com> User-Agent: Mutt/1.5.23+102 (2ca89bed6448) (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2202 Lines: 66 On Fri, Jul 24, 2015 at 08:48:11AM +0200, Petr Tesarik wrote: > From: Petr Tesarik > > Make it possible to read the cp210x part number from userspace by making > it a sysfs attribute. > > Signed-off-by: Petr Tesarik All sysfs files need to be documented in Documentation/ABI/ > --- > drivers/usb/serial/cp210x.c | 21 ++++++++++++++++++++- > 1 file changed, 20 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c > index dbfc722..66de350 100644 > --- a/drivers/usb/serial/cp210x.c > +++ b/drivers/usb/serial/cp210x.c > @@ -871,11 +871,24 @@ static void cp210x_break_ctl(struct tty_struct *tty, int break_state) > cp210x_set_config(port, CP210X_SET_BREAK, &state, 2); > } > > +static ssize_t part_number_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct usb_interface *intf = to_usb_interface(dev); > + struct usb_serial *serial = usb_get_intfdata(intf); > + struct cp210x_serial_private *spriv = usb_get_serial_data(serial); > + > + return sprintf(buf, "%i\n", spriv->bPartNumber); > +} > + > +static DEVICE_ATTR_RO(part_number); > + > static int cp210x_startup(struct usb_serial *serial) > { > struct usb_host_interface *cur_altsetting; > struct cp210x_serial_private *spriv; > unsigned int partnum; > + int result; > > spriv = kzalloc(sizeof(*spriv), GFP_KERNEL); > if (!spriv) > @@ -892,13 +905,19 @@ static int cp210x_startup(struct usb_serial *serial) > &partnum, 1, USB_CTRL_GET_TIMEOUT); > spriv->bPartNumber = partnum & 0xFF; > > - return 0; > + result = device_create_file(&serial->interface->dev, > + &dev_attr_part_number); You just raced with userspace, it will not properly see this attribute :( Please never use device_create_file, use an attribute group assigned to the tty device. Not the USB interface, that is only for USB interface "things". thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/