[PATCH 0/7] BKL removal follow-up

[PATCH 0/7] BKL removal follow-up

[Arnd Bergmann]

Hi Linus,

It seems the v4l and udf code has been worked out now and patches
to kill the BKL there are finally making it upstream.

As promised, here are the patches I did since the kernel summit
to turn off the BKL by default. Given that -rc2 is out now, I don't
know how much of these you still want for 2.6.37, so just pick
the ones you like and I'll send a pull request for the rest
once the 2.6.38 merge window opens.

The patches have been in -next for three days, and I fixed up
the two problems that this has revealed. I would have liked
to give them more testing and wait until you have pulled the
UDF patches, but I'm planning to be offline until next Wednesday.

	Arnd

Arnd Bergmann (7):
  staging/stradis: mark as "depends on BKL"
  drm/i810: remove the BKL
  BKL: remove extraneous #include <smp_lock.h>
  BKL: remove references to lock_kernel from comments
  BKL: disable by default
  BKL: mark lock_kernel as deprecated
  BKL: move CONFIG_BKL to staging

 arch/blackfin/kernel/process.c                     |    1 -
 arch/frv/kernel/process.c                          |    1 -
 arch/h8300/kernel/process.c                        |    1 -
 arch/m68k/kernel/process.c                         |    1 -
 arch/m68knommu/kernel/process.c                    |    1 -
 arch/mn10300/kernel/process.c                      |    1 -
 arch/parisc/hpux/sys_hpux.c                        |    1 -
 arch/parisc/kernel/sys_parisc32.c                  |    1 -
 arch/powerpc/kernel/sys_ppc32.c                    |    1 -
 arch/s390/kernel/compat_linux.c                    |    1 -
 arch/sparc/kernel/leon_smp.c                       |    1 -
 arch/sparc/kernel/sys_sparc32.c                    |    1 -
 arch/sparc/kernel/sys_sparc_32.c                   |    1 -
 arch/sparc/kernel/unaligned_32.c                   |    1 -
 arch/sparc/kernel/windows.c                        |    1 -
 arch/tile/kernel/compat.c                          |    1 -
 arch/tile/kernel/compat_signal.c                   |    1 -
 arch/tile/kernel/signal.c                          |    1 -
 arch/tile/kernel/smpboot.c                         |    1 -
 arch/tile/kernel/sys.c                             |    1 -
 arch/tile/mm/fault.c                               |    1 -
 arch/tile/mm/hugetlbpage.c                         |    1 -
 arch/um/kernel/exec.c                              |    1 -
 arch/x86/ia32/sys_ia32.c                           |    1 -
 arch/x86/kernel/cpuid.c                            |    1 -
 arch/x86/kernel/msr.c                              |    1 -
 block/compat_ioctl.c                               |    1 -
 block/ioctl.c                                      |    1 -
 drivers/block/drbd/drbd_receiver.c                 |    1 -
 drivers/block/drbd/drbd_worker.c                   |    1 -
 drivers/char/agp/frontend.c                        |    1 -
 drivers/char/amiserial.c                           |    1 -
 drivers/char/briq_panel.c                          |    1 -
 drivers/char/hpet.c                                |    1 -
 drivers/char/hw_random/core.c                      |    1 -
 drivers/char/istallion.c                           |    1 -
 drivers/char/serial167.c                           |    1 -
 drivers/char/specialix.c                           |    1 -
 drivers/char/stallion.c                            |    1 -
 drivers/char/sx.c                                  |    1 -
 drivers/char/uv_mmtimer.c                          |    1 -
 drivers/gpu/drm/Kconfig                            |    4 ++--
 drivers/gpu/drm/drm_fops.c                         |    1 -
 drivers/gpu/drm/i810/i810_dma.c                    |   18 +-----------------
 drivers/gpu/drm/i810/i810_drv.c                    |    6 +++++-
 drivers/hid/hidraw.c                               |    1 -
 drivers/hid/usbhid/hiddev.c                        |    1 -
 drivers/infiniband/hw/ipath/ipath_file_ops.c       |    1 -
 drivers/input/input.c                              |    1 -
 drivers/input/serio/serio_raw.c                    |    1 -
 drivers/media/dvb/dvb-core/dvb_ca_en50221.c        |    1 -
 drivers/media/dvb/dvb-core/dvb_frontend.c          |    1 -
 drivers/media/dvb/ngene/ngene-core.c               |    1 -
 drivers/media/dvb/ngene/ngene-dvb.c                |    1 -
 drivers/media/dvb/ngene/ngene-i2c.c                |    1 -
 drivers/media/radio/radio-mr800.c                  |    1 -
 drivers/media/radio/si470x/radio-si470x.h          |    1 -
 drivers/media/video/bt8xx/bttv-driver.c            |    1 -
 drivers/media/video/cx88/cx88-blackbird.c          |    1 -
 drivers/media/video/cx88/cx88-video.c              |    1 -
 drivers/media/video/pwc/pwc-if.c                   |    1 -
 drivers/media/video/s2255drv.c                     |    1 -
 drivers/media/video/saa7134/saa7134-empress.c      |    1 -
 drivers/media/video/saa7164/saa7164.h              |    1 -
 drivers/media/video/usbvision/usbvision-video.c    |    1 -
 drivers/media/video/v4l2-compat-ioctl32.c          |    1 -
 drivers/net/wireless/orinoco/orinoco_usb.c         |    1 -
 drivers/parisc/eisa_eeprom.c                       |    1 -
 drivers/pci/proc.c                                 |    1 -
 drivers/pnp/isapnp/proc.c                          |    1 -
 drivers/s390/block/dasd_eer.c                      |    1 -
 drivers/s390/char/fs3270.c                         |    1 -
 drivers/s390/char/tape_char.c                      |    1 -
 drivers/s390/char/vmlogrdr.c                       |    1 -
 drivers/s390/char/vmur.c                           |    1 -
 drivers/s390/crypto/zcrypt_api.c                   |    1 -
 drivers/scsi/hpsa.c                                |    1 -
 drivers/scsi/pm8001/pm8001_sas.h                   |    1 -
 drivers/scsi/sd.c                                  |    1 -
 drivers/serial/crisv10.c                           |    1 -
 drivers/serial/serial_core.c                       |    1 -
 drivers/staging/Kconfig                            |   11 +++++++++++
 drivers/staging/cx25821/cx25821.h                  |    1 -
 drivers/staging/easycap/easycap.h                  |    1 -
 .../staging/intel_sst/intel_sst_app_interface.c    |    1 -
 drivers/staging/rtl8712/osdep_service.h            |    1 -
 drivers/staging/speakup/buffers.c                  |    1 -
 drivers/staging/stradis/Kconfig                    |    2 +-
 drivers/usb/core/devices.c                         |    1 -
 drivers/usb/core/devio.c                           |    1 -
 drivers/usb/core/file.c                            |    1 -
 drivers/usb/core/inode.c                           |    1 -
 drivers/usb/gadget/f_fs.c                          |    1 -
 drivers/usb/gadget/f_hid.c                         |    1 -
 drivers/usb/host/isp1362-hcd.c                     |    1 -
 drivers/usb/host/uhci-debug.c                      |    1 -
 drivers/usb/mon/mon_bin.c                          |    1 -
 drivers/usb/mon/mon_stat.c                         |    1 -
 drivers/usb/serial/usb-serial.c                    |    1 -
 drivers/video/console/vgacon.c                     |    1 -
 drivers/xen/xenfs/privcmd.c                        |    1 -
 drivers/zorro/proc.c                               |    1 -
 fs/block_dev.c                                     |    1 -
 fs/ceph/inode.c                                    |    1 -
 fs/ceph/mds_client.c                               |    1 -
 fs/compat_ioctl.c                                  |    1 -
 fs/ecryptfs/super.c                                |    1 -
 fs/ext3/super.c                                    |    1 -
 fs/ioctl.c                                         |    1 -
 fs/lockd/clntlock.c                                |    1 -
 fs/lockd/clntproc.c                                |    1 -
 fs/lockd/svc4proc.c                                |    1 -
 fs/lockd/svclock.c                                 |    1 -
 fs/lockd/svcproc.c                                 |    1 -
 fs/locks.c                                         |    1 -
 fs/namespace.c                                     |    1 -
 fs/ncpfs/dir.c                                     |    1 -
 fs/ncpfs/file.c                                    |    1 -
 fs/ncpfs/inode.c                                   |    1 -
 fs/ncpfs/ioctl.c                                   |    1 -
 fs/nfs/callback.c                                  |    1 -
 fs/nfs/delegation.c                                |    1 -
 fs/nfs/super.c                                     |    1 -
 fs/nfsd/nfs4state.c                                |    8 ++++----
 fs/ocfs2/super.c                                   |    1 -
 fs/proc/inode.c                                    |    1 -
 fs/read_write.c                                    |    1 -
 fs/reiserfs/inode.c                                |    1 -
 fs/reiserfs/ioctl.c                                |    1 -
 fs/reiserfs/journal.c                              |    1 -
 fs/reiserfs/super.c                                |    1 -
 include/linux/hardirq.h                            |    1 -
 include/linux/reiserfs_fs.h                        |    1 -
 include/linux/smp_lock.h                           |   15 ++-------------
 include/linux/tty.h                                |    1 -
 init/main.c                                        |    1 -
 kernel/trace/trace.c                               |    1 -
 lib/Kconfig.debug                                  |    9 ---------
 net/irda/af_irda.c                                 |    1 -
 net/irda/irnet/irnet_ppp.c                         |    1 -
 net/sunrpc/svc_xprt.c                              |    1 -
 sound/core/info.c                                  |    1 -
 sound/core/pcm_native.c                            |    1 -
 sound/core/sound.c                                 |    1 -
 sound/sound_core.c                                 |    1 -
 145 files changed, 26 insertions(+), 184 deletions(-)

Cc: Nathan Laredo <laredo-mXXj517/zsQ@public.gmane.org>
Cc: Greg Kroah-Hartman <gregkh-l3A5Bk7waGM@public.gmane.org>
Cc: Dave Airlie <airlied-cv59FeDIM0c@public.gmane.org>
Cc: dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
Cc: "J. Bruce Fields" <bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
Cc: linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Alessio Igor Bogani <alessioigorbogani-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Jan Kara <jack-AlSwsSmVLrQ@public.gmane.org>
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[PATCH 2/7] drm/i810: remove the BKL

[Arnd Bergmann]

SMP i810 systems were practically nonexistent and the configuration
was not officially supported by Intel at the time when Pentium-III
was common.

With this change, it is still possible to build a distribution kernel
that has support for SMP and includes the i810 driver without the BKL.
As a precaution, check for the theoretical SMP case at run time and
refuse to load the driver.

We also need to disable CONFIG_PREEMPT builds for this driver.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Airlie <airlied@linux.ie>
Cc: dri-devel@lists.freedesktop.org
---
 drivers/gpu/drm/Kconfig         |    4 ++--
 drivers/gpu/drm/i810/i810_dma.c |   18 +-----------------
 drivers/gpu/drm/i810/i810_drv.c |    6 +++++-
 3 files changed, 8 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 7af4436..ddc122f 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -73,8 +73,8 @@ source "drivers/gpu/drm/radeon/Kconfig"
 
 config DRM_I810
 	tristate "Intel I810"
-	# BKL usage in order to avoid AB-BA deadlocks, may become BROKEN_ON_SMP
-	depends on DRM && AGP && AGP_INTEL && BKL
+	# !PREEMPT because of missing ioctl locking
+	depends on DRM && AGP && AGP_INTEL && (!PREEMPT || BROKEN)
 	help
 	  Choose this option if you have an Intel I810 graphics card.  If M is
 	  selected, the module will be called i810.  AGP support is required
diff --git a/drivers/gpu/drm/i810/i810_dma.c b/drivers/gpu/drm/i810/i810_dma.c
index ff33e53..8f371e8 100644
--- a/drivers/gpu/drm/i810/i810_dma.c
+++ b/drivers/gpu/drm/i810/i810_dma.c
@@ -37,7 +37,6 @@
 #include <linux/interrupt.h>	/* For task queue support */
 #include <linux/delay.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
 #include <linux/pagemap.h>
 
 #define I810_BUF_FREE		2
@@ -94,7 +93,6 @@ static int i810_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
 	struct drm_buf *buf;
 	drm_i810_buf_priv_t *buf_priv;
 
-	lock_kernel();
 	dev = priv->minor->dev;
 	dev_priv = dev->dev_private;
 	buf = dev_priv->mmap_buffer;
@@ -104,7 +102,6 @@ static int i810_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
 	vma->vm_file = filp;
 
 	buf_priv->currently_mapped = I810_BUF_MAPPED;
-	unlock_kernel();
 
 	if (io_remap_pfn_range(vma, vma->vm_start,
 			       vma->vm_pgoff,
@@ -116,7 +113,7 @@ static int i810_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
 static const struct file_operations i810_buffer_fops = {
 	.open = drm_open,
 	.release = drm_release,
-	.unlocked_ioctl = i810_ioctl,
+	.unlocked_ioctl = drm_ioctl,
 	.mmap = i810_mmap_buffers,
 	.fasync = drm_fasync,
 	.llseek = noop_llseek,
@@ -1242,19 +1239,6 @@ int i810_driver_dma_quiescent(struct drm_device *dev)
 	return 0;
 }
 
-/*
- * call the drm_ioctl under the big kernel lock because
- * to lock against the i810_mmap_buffers function.
- */
-long i810_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
-	int ret;
-	lock_kernel();
-	ret = drm_ioctl(file, cmd, arg);
-	unlock_kernel();
-	return ret;
-}
-
 struct drm_ioctl_desc i810_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(I810_INIT, i810_dma_init, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY|DRM_UNLOCKED),
 	DRM_IOCTL_DEF_DRV(I810_VERTEX, i810_dma_vertex, DRM_AUTH|DRM_UNLOCKED),
diff --git a/drivers/gpu/drm/i810/i810_drv.c b/drivers/gpu/drm/i810/i810_drv.c
index 88bcd33..0152fa2 100644
--- a/drivers/gpu/drm/i810/i810_drv.c
+++ b/drivers/gpu/drm/i810/i810_drv.c
@@ -57,7 +57,7 @@ static struct drm_driver driver = {
 		 .owner = THIS_MODULE,
 		 .open = drm_open,
 		 .release = drm_release,
-		 .unlocked_ioctl = i810_ioctl,
+		 .unlocked_ioctl = drm_ioctl,
 		 .mmap = drm_mmap,
 		 .poll = drm_poll,
 		 .fasync = drm_fasync,
@@ -79,6 +79,10 @@ static struct drm_driver driver = {
 
 static int __init i810_init(void)
 {
+	if (num_possible_cpus() > 1) {
+		pr_err("drm/i810 does not support SMP\n");
+		return -EINVAL;
+	}
 	driver.num_ioctls = i810_max_ioctl;
 	return drm_init(&driver);
 }
-- 
1.7.1

Re: [PATCH 0/7] BKL removal follow-up

[Jan Kara]

  Hi,

On Wed 17-11-10 16:26:52, Arnd Bergmann wrote:
> It seems the v4l and udf code has been worked out now and patches
> to kill the BKL there are finally making it upstream.
> 
> As promised, here are the patches I did since the kernel summit
> to turn off the BKL by default. Given that -rc2 is out now, I don't
> know how much of these you still want for 2.6.37, so just pick
> the ones you like and I'll send a pull request for the rest
> once the 2.6.38 merge window opens.
  Just for info, UDF BKL removal patches seem to work fine but I want to
give them some final SMP testing on Monday before pushing them to -next.
I'm not sure how much people hurry with disabling the lock so if I should
push them ASAP or whether the next merge window is fine...

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

Re: [PATCH 0/7] BKL removal follow-up

[Linus Torvalds]

On Thu, Nov 18, 2010 at 3:34 PM, Jan Kara <jack-AlSwsSmVLrQ@public.gmane.org> wrote:
>
>  Just for info, UDF BKL removal patches seem to work fine but I want to
> give them some final SMP testing on Monday before pushing them to -next.
> I'm not sure how much people hurry with disabling the lock so if I should
> push them ASAP or whether the next merge window is fine...

I don't think I can reasonably do it in 37, we're late enough in the
-rc series. So UDF and really saying 'n' to BKL by default will have
to be for the next merge window.

I hate to do it, but I'd be too nervous about it any other way.

                   Linus
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Re: [PATCH 0/7] BKL removal follow-up

[Boaz Harrosh]

On 11/19/2010 01:40 AM, Linus Torvalds wrote:
> On Thu, Nov 18, 2010 at 3:34 PM, Jan Kara <jack-AlSwsSmVLrQ@public.gmane.org> wrote:
>>
>>  Just for info, UDF BKL removal patches seem to work fine but I want to
>> give them some final SMP testing on Monday before pushing them to -next.
>> I'm not sure how much people hurry with disabling the lock so if I should
>> push them ASAP or whether the next merge window is fine...
> 
> I don't think I can reasonably do it in 37, we're late enough in the
> -rc series. So UDF and really saying 'n' to BKL by default will have
> to be for the next merge window.
> 
> I hate to do it, but I'd be too nervous about it any other way.
> 
>                    Linus

Could it not default to "n" but be SELECTed by the like of UDF. Or
that too big of a Kconfig change for 37-rcX? I understand it does
not really buy us anything for distro's with allmodconfig style,
but it should help with defconfig on all the other ARCH's.

Thanks
Boaz
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Re: [PATCH 0/7] BKL removal follow-up

[Linus Torvalds]

On Sun, Nov 21, 2010 at 6:12 AM, Boaz Harrosh <openosd-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On 11/19/2010 01:40 AM, Linus Torvalds wrote:
>>
>> I don't think I can reasonably do it in 37, we're late enough in the
>> -rc series. So UDF and really saying 'n' to BKL by default will have
>> to be for the next merge window.
>
> Could it not default to "n" but be SELECTed by the like of UDF. Or
> that too big of a Kconfig change for 37-rcX? I understand it does
> not really buy us anything for distro's with allmodconfig style,
> but it should help with defconfig on all the other ARCH's.

Yes, I'd be ok with UDF doing a "select BKL" along with a "default n"
for BKL itself.

I think UDF currently is the only sane reason to have BKL enabled any
more, and yes, it would probably make it easier to configure things.

Tested patch?

                       Linus
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Re: [PATCH 0/7] BKL removal follow-up

[Nick Bowler]

On 2010-11-21 09:45 -0800, Linus Torvalds wrote:
> Yes, I'd be ok with UDF doing a "select BKL" along with a "default n"
> for BKL itself.
> 
> I think UDF currently is the only sane reason to have BKL enabled any
> more, and yes, it would probably make it easier to configure things.

UFS (which I use) also relies on BKL.

-- 
Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/)