Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751286Ab0AaF3u (ORCPT ); Sun, 31 Jan 2010 00:29:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751155Ab0AaF3t (ORCPT ); Sun, 31 Jan 2010 00:29:49 -0500 Received: from mail-pz0-f201.google.com ([209.85.222.201]:59650 "EHLO mail-pz0-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750882Ab0AaF3s (ORCPT ); Sun, 31 Jan 2010 00:29:48 -0500 X-Greylist: delayed 78237 seconds by postgrey-1.27 at vger.kernel.org; Sun, 31 Jan 2010 00:29:48 EST DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=gpzuoPjo4+6AtfisUcrPufHlLTCV/xlJ8DTv4wjDyiH5Wxx8jITyjXT2QIv3onxVpH HH0vmlRPUVAtgbpKlxaCTVA3OEGiifRMAAP/BSw3x57iQz5CKpnAGiHIEnBgsOEtWfvI JpaUyA1dyzRgLJgjAuI8RflAoasqgd8zMICgs= Date: Sat, 30 Jan 2010 21:29:42 -0800 From: Dmitry Torokhov To: Arnd Bergmann Cc: John Kacur , Thadeu Lima de Souza Cascardo , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] input: remove BKL from uinput open function Message-ID: <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201001310520.55813.arnd@arndb.de> User-Agent: Mutt/1.5.20 (2009-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2354 Lines: 70 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; } -- 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/