Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755987Ab0BAUWH (ORCPT ); Mon, 1 Feb 2010 15:22:07 -0500 Received: from mail-ew0-f228.google.com ([209.85.219.228]:46850 "EHLO mail-ew0-f228.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754821Ab0BAUWD convert rfc822-to-8bit (ORCPT ); Mon, 1 Feb 2010 15:22:03 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=wcGmgyANgbGfzjYdbss3Os9zWfu1g16XoYPqRSVg2nue9NzWZCImOqC+JTJ6ubnt5w GP7L7B2d9sCXe3jHGD0VZB2crVrKznBxKCzYv9YzToPhdQhEB5bQ+9S9tCoUoseGBey9 MFrYrOMMIpV9AXSbkRDAzn4JlKR/YFM4DQaJI= MIME-Version: 1.0 In-Reply-To: <20100131052942.GA12320@core.coreip.homeip.net> References: <1264800197-29523-1-git-send-email-cascardo@holoscopio.com> <201001302257.09354.arnd@arndb.de> <520f0cf11001301507k20e3cf8dqa73026e12f3a1767@mail.gmail.com> <201001310520.55813.arnd@arndb.de> <20100131052942.GA12320@core.coreip.homeip.net> Date: Mon, 1 Feb 2010 21:22:01 +0100 X-Google-Sender-Auth: 296efc3ca74e7686 Message-ID: <520f0cf11002011222h134dbf06rf1db612da9a9728@mail.gmail.com> Subject: Re: [PATCH] input: remove BKL from uinput open function From: John Kacur To: Dmitry Torokhov Cc: Arnd Bergmann , Thadeu Lima de Souza Cascardo , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3113 Lines: 90 On Sun, Jan 31, 2010 at 6:29 AM, Dmitry Torokhov wrote: > On Sun, Jan 31, 2010 at 05:20:55AM +0100, Arnd Bergmann wrote: >> On Sunday 31 January 2010, John Kacur wrote: >> > > Sorry, I should have been clearer, but not implementing llseek >> > > is the problem I was referring to: When a driver has no explicit >> > > .llseek operation in its file operations and does not call >> > > nonseekable_open from its open operation, the VFS layer will >> > > implicitly use default_llseek, which takes the BKL. We're >> > > in the process of changing drivers not to do this, one by one >> > > so we can kill the BKL in the end. >> > > >> > >> > I know we've discussed this before, but why wouldn't the following >> > make more sense? >> > ?.llseek ? ? ? ? = no_llseek, >> >> That's one of the possible solutions. Assigning it to generic_file_llseek >> also gets rid of the BKL but keeps the current behaviour (calling seek >> returns success without having an effect, no_llseek returns -ESPIPE), >> while calling nonseekable_open has the other side-effect of making >> pread/pwrite fail with -ESPIPE, which is more consistent than >> only failing seek. >> > > OK, so how about the patch below (on top of Thadeu's patch)? > > -- > Dmitry > > Input: uinput - use nonseekable_open > > Seeking does not make sense for uinput so let's use nonseekable_open > to mark the device non-seekable. > > Signed-off-by: Dmitry Torokhov > --- > > ?drivers/input/misc/uinput.c | ? ?7 +++++++ > ?1 files changed, 7 insertions(+), 0 deletions(-) > > > diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c > index 18206e1..7089151 100644 > --- a/drivers/input/misc/uinput.c > +++ b/drivers/input/misc/uinput.c > @@ -278,6 +278,7 @@ static int uinput_create_device(struct uinput_device *udev) > ?static int uinput_open(struct inode *inode, struct file *file) > ?{ > ? ? ? ?struct uinput_device *newdev; > + ? ? ? int error; > > ? ? ? ?newdev = kzalloc(sizeof(struct uinput_device), GFP_KERNEL); > ? ? ? ?if (!newdev) > @@ -291,6 +292,12 @@ static int uinput_open(struct inode *inode, struct file *file) > > ? ? ? ?file->private_data = newdev; > > + ? ? ? error = nonseekable_open(inode, file); > + ? ? ? if (error) { > + ? ? ? ? ? ? ? kfree(newdev); > + ? ? ? ? ? ? ? return error; > + ? ? ? } > + > ? ? ? ?return 0; > ?} > > Hmnn, if you look at nonseekable_open() it will always return 0. I think you can just do the following. diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c index 18206e1..697c0a6 100644 --- a/drivers/input/misc/uinput.c +++ b/drivers/input/misc/uinput.c @@ -291,7 +291,7 @@ static int uinput_open(struct inode *inode, struct file *fil file->private_data = newdev; - return 0; + return nonseekable_open(inode, file); } Signed-off-by: John Kacur -- 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/