Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754175AbZCXWfq (ORCPT ); Tue, 24 Mar 2009 18:35:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752856AbZCXWfd (ORCPT ); Tue, 24 Mar 2009 18:35:33 -0400 Received: from wf-out-1314.google.com ([209.85.200.174]:27976 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751190AbZCXWfc convert rfc822-to-8bit (ORCPT ); Tue, 24 Mar 2009 18:35:32 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=ToCPsGRdL2W4VGGAsMBLYewUTnVfM7FicjxbwQtNbFawyS9Y2P3R3SqVnxYpOvUFas 5MznICxIbIuQoszw3By3DLXRNobak5xyQAsLE4nZIBLdEUfjeOYRqv32aLlvZDvmI869 9ZpVbtf1Do3RVcoQ/XFGD3+lBjb4ZS9dNGkeU= MIME-Version: 1.0 In-Reply-To: <1237933535.9222.12.camel@tux.localhost> References: <1237930711-16200-1-git-send-email-stoyboyker@gmail.com> <1237933535.9222.12.camel@tux.localhost> Date: Tue, 24 Mar 2009 17:35:30 -0500 Message-ID: <6d291e080903241535x7002f01fq9f42ce594ea8ee91@mail.gmail.com> Subject: Re: [PATCH 12/13][Resubmit][drivers/media] changed ioctls to unlocked From: Stoyan Gaydarov To: Alexey Klimov Cc: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3903 Lines: 109 On Tue, Mar 24, 2009 at 5:25 PM, Alexey Klimov wrote: > Hello, Stoyan > > On Tue, 2009-03-24 at 16:38 -0500, stoyboyker@gmail.com wrote: >> From: Stoyan Gaydarov >> >> Signed-off-by: Stoyan Gaydarov >> --- >>  drivers/media/dvb/bt8xx/dst_ca.c |    7 +++++-- >>  drivers/media/video/dabusb.c     |   11 ++++++++--- >>  2 files changed, 13 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/media/dvb/bt8xx/dst_ca.c b/drivers/media/dvb/bt8xx/dst_ca.c >> index 0258451..d3487c5 100644 >> --- a/drivers/media/dvb/bt8xx/dst_ca.c >> +++ b/drivers/media/dvb/bt8xx/dst_ca.c >> @@ -552,8 +552,10 @@ free_mem_and_exit: >>       return result; >>  } >> >> -static int dst_ca_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long ioctl_arg) >> +static long dst_ca_ioctl(struct file *file, unsigned int cmd, unsigned long ioctl_arg) >>  { >> +     lock_kernel(); >> + >>       struct dvb_device* dvbdev = (struct dvb_device*) file->private_data; >>       struct dst_state* state = (struct dst_state*) dvbdev->priv; >>       struct ca_slot_info *p_ca_slot_info; >> @@ -647,6 +649,7 @@ static int dst_ca_ioctl(struct inode *inode, struct file *file, unsigned int cmd >>       kfree (p_ca_slot_info); >>       kfree (p_ca_caps); >> >> +     unlock_kernel(); >>       return result; >>  } >> >> @@ -684,7 +687,7 @@ static ssize_t dst_ca_write(struct file *file, const char __user *buffer, size_t >> >>  static struct file_operations dst_ca_fops = { >>       .owner = THIS_MODULE, >> -     .ioctl = dst_ca_ioctl, >> +     .unlocked_ioctl = dst_ca_ioctl, >>       .open = dst_ca_open, >>       .release = dst_ca_release, >>       .read = dst_ca_read, >> diff --git a/drivers/media/video/dabusb.c b/drivers/media/video/dabusb.c >> index 298810d..c31e76f 100644 >> --- a/drivers/media/video/dabusb.c >> +++ b/drivers/media/video/dabusb.c >> @@ -657,22 +657,26 @@ static int dabusb_release (struct inode *inode, struct file *file) >>       return 0; >>  } >> >> -static int dabusb_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) >> +static long dabusb_ioctl (struct file *file, unsigned int cmd, unsigned long arg) >>  { >>       pdabusb_t s = (pdabusb_t) file->private_data; >>       pbulk_transfer_t pbulk; >>       int ret = 0; >>       int version = DABUSB_VERSION; >> >> +     lock_kernel(); >>       dbg("dabusb_ioctl"); >> >> -     if (s->remove_pending) >> +     if (s->remove_pending) { >> +             unlock_kernel(); >>               return -EIO; >> +     } >> >>       mutex_lock(&s->mutex); >> >>       if (!s->usbdev) { >>               mutex_unlock(&s->mutex); >> +             unlock_kernel(); >>               return -EIO; >>       } >> >> @@ -713,6 +717,7 @@ static int dabusb_ioctl (struct inode *inode, struct file *file, unsigned int cm >>               break; >>       } >>       mutex_unlock(&s->mutex); >> +     unlock_kernel(); > > May i ask why big kernel lock is used here? > Where is an advantage of BKL here? > Why not to use, for example, one more mutex lock? The big kernel lock was already being used here, the call to ioctl is surrounded by lock/unlock kernel, this patch just pushes it down so that the __locked__ ioctl can be removed and also makes the maintainers of the code aware that the lock was there. If the lock is not needed then it can be removed and the function can remain under the unlocked_ioctl. > > -- > Best regards, Klimov Alexey > > -- -Stoyan -- 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/