[PATCH] drm: Release spinlock for calling lastclose() after 58474713

[PATCH] drm: Release spinlock for calling lastclose() after 58474713

[Chris Wilson]

When removing of the BKL the locking around lastclose() was rearranged
and resulted in the holding of the open_count spinlock over the call
into drm_lastclose(). The drivers were not ready for this path to be
atomic - it may indeed involve long waits to release old objects and
cleanup the GPU - and so we ended up scheduling whilst atomic.

[   54.625598] BUG: scheduling while atomic: X/3546/0x00000002
[   54.625600] Modules linked in: sco bridge stp llc input_polldev rfcomm bnep l2cap crc16 sch_sfq ipv6 md_mod acpi_cpufreq mperf cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt dm_mod btusb bluetooth usbhid hid zaurus cdc_ether usbnet mii cdc_wdm cdc_acm uvcvideo videodev v4l1_compat v4l2_compat_ioctl32 snd_hda_codec_conexant arc4 pcmcia ecb snd_hda_intel joydev sdhci_pci sdhci snd_hda_codec tpm_tis firewire_ohci mmc_core e1000e uhci_hcd thinkpad_acpi nvram yenta_socket pcmcia_rsrc pcmcia_core tpm wmi sr_mod firewire_core iwlagn ehci_hcd snd_hwdep snd_pcm usbcore tpm_bios thermal led_class snd_timer iwlcore snd soundcore ac snd_page_alloc pcspkr psmouse serio_raw battery sg mac80211 evdev cfg80211 i2c_i801 iTCO_wdt iTCO_vendor_support cdrom processor crc_itu_t rfkill xfs exportfs sd_m
 od crc_t10dif ahci libahci libata scsi_mod [last unloaded: scsi_wait_scan]
[   54.625663] Pid: 3546, comm: X Not tainted 2.6.35-04771-g1787985 #301
[   54.625665] Call Trace:
[   54.625671]  [<ffffffff8102d599>] __schedule_bug+0x57/0x5c
[   54.625675]  [<ffffffff81384141>] schedule+0xe5/0x832
[   54.625679]  [<ffffffff81163e77>] ? put_dec+0x20/0x3c
[   54.625682]  [<ffffffff81384dd4>] schedule_timeout+0x275/0x29f
[   54.625686]  [<ffffffff810455e1>] ? process_timeout+0x0/0xb
[   54.625688]  [<ffffffff81384e17>] schedule_timeout_uninterruptible+0x19/0x1b
[   54.625691]  [<ffffffff81045893>] msleep+0x16/0x1d
[   54.625695]  [<ffffffff812a2e53>] i9xx_crtc_dpms+0x273/0x2ae
[   54.625698]  [<ffffffff812a18be>] intel_crtc_dpms+0x28/0xe7
[   54.625702]  [<ffffffff811ec0fa>] drm_helper_disable_unused_functions+0xf0/0x118
[   54.625705]  [<ffffffff811ecde3>] drm_crtc_helper_set_config+0x644/0x7c8
[   54.625708]  [<ffffffff811f12dd>] ? drm_copy_field+0x40/0x50
[   54.625711]  [<ffffffff811ebca2>] drm_fb_helper_force_kernel_mode+0x3e/0x85
[   54.625713]  [<ffffffff811ebcf2>] drm_fb_helper_restore+0x9/0x24
[   54.625717]  [<ffffffff81290a41>] i915_driver_lastclose+0x2b/0x5c
[   54.625720]  [<ffffffff811f14a7>] drm_lastclose+0x44/0x2ad
[   54.625722]  [<ffffffff811f1ed2>] drm_release+0x5c6/0x609
[   54.625726]  [<ffffffff810d1275>] fput+0x109/0x1c7
[   54.625728]  [<ffffffff810ce5e4>] filp_close+0x61/0x6b
[   54.625731]  [<ffffffff810ce680>] sys_close+0x92/0xd4
[   54.625734]  [<ffffffff81002a2b>] system_call_fastpath+0x16/0x1b

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/drm_fops.c |    9 ++++-----
 1 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index 2ca8df8..6367961 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -572,16 +572,15 @@ int drm_release(struct inode *inode, struct file *filp)
 	atomic_inc(&dev->counts[_DRM_STAT_CLOSES]);
 	spin_lock(&dev->count_lock);
 	if (!--dev->open_count) {
+		spin_unlock(&dev->count_lock);
+
 		if (atomic_read(&dev->ioctl_count)) {
 			DRM_ERROR("Device busy: %d\n",
 				  atomic_read(&dev->ioctl_count));
 			retcode = -EBUSY;
-			goto out;
-		}
-		retcode = drm_lastclose(dev);
+		} else
+			retcode = drm_lastclose(dev);
 	}
-out:
-	spin_unlock(&dev->count_lock);
 	mutex_unlock(&drm_global_mutex);
 
 	return retcode;
-- 
1.7.1

Re: [PATCH] drm: Release spinlock for calling lastclose() after 58474713

[Dave Airlie]

On Sat, Aug 7, 2010 at 10:49 PM, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> When removing of the BKL the locking around lastclose() was rearranged
> and resulted in the holding of the open_count spinlock over the call
> into drm_lastclose(). The drivers were not ready for this path to be
> atomic - it may indeed involve long waits to release old objects and
> cleanup the GPU - and so we ended up scheduling whilst atomic.

I might be missing something, but what stops the race with something
reopening while we are in lastclose now?

Dave.

>
> [   54.625598] BUG: scheduling while atomic: X/3546/0x00000002
> [   54.625600] Modules linked in: sco bridge stp llc input_polldev rfcomm bnep l2cap crc16 sch_sfq ipv6 md_mod acpi_cpufreq mperf cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt dm_mod btusb bluetooth usbhid hid zaurus cdc_ether usbnet mii cdc_wdm cdc_acm uvcvideo videodev v4l1_compat v4l2_compat_ioctl32 snd_hda_codec_conexant arc4 pcmcia ecb snd_hda_intel joydev sdhci_pci sdhci snd_hda_codec tpm_tis firewire_ohci mmc_core e1000e uhci_hcd thinkpad_acpi nvram yenta_socket pcmcia_rsrc pcmcia_core tpm wmi sr_mod firewire_core iwlagn ehci_hcd snd_hwdep snd_pcm usbcore tpm_bios thermal led_class snd_timer iwlcore snd soundcore ac snd_page_alloc pcspkr psmouse serio_raw battery sg mac80211 evdev cfg80211 i2c_i801 iTCO_wdt iTCO_vendor_support cdrom processor crc_itu_t rfkill xfs exportfs sd_mod crc_t10dif ahci libahci libata scsi_mod [last unloaded: scsi_wait_scan]
> [   54.625663] Pid: 3546, comm: X Not tainted 2.6.35-04771-g1787985 #301
> [   54.625665] Call Trace:
> [   54.625671]  [<ffffffff8102d599>] __schedule_bug+0x57/0x5c
> [   54.625675]  [<ffffffff81384141>] schedule+0xe5/0x832
> [   54.625679]  [<ffffffff81163e77>] ? put_dec+0x20/0x3c
> [   54.625682]  [<ffffffff81384dd4>] schedule_timeout+0x275/0x29f
> [   54.625686]  [<ffffffff810455e1>] ? process_timeout+0x0/0xb
> [   54.625688]  [<ffffffff81384e17>] schedule_timeout_uninterruptible+0x19/0x1b
> [   54.625691]  [<ffffffff81045893>] msleep+0x16/0x1d
> [   54.625695]  [<ffffffff812a2e53>] i9xx_crtc_dpms+0x273/0x2ae
> [   54.625698]  [<ffffffff812a18be>] intel_crtc_dpms+0x28/0xe7
> [   54.625702]  [<ffffffff811ec0fa>] drm_helper_disable_unused_functions+0xf0/0x118
> [   54.625705]  [<ffffffff811ecde3>] drm_crtc_helper_set_config+0x644/0x7c8
> [   54.625708]  [<ffffffff811f12dd>] ? drm_copy_field+0x40/0x50
> [   54.625711]  [<ffffffff811ebca2>] drm_fb_helper_force_kernel_mode+0x3e/0x85
> [   54.625713]  [<ffffffff811ebcf2>] drm_fb_helper_restore+0x9/0x24
> [   54.625717]  [<ffffffff81290a41>] i915_driver_lastclose+0x2b/0x5c
> [   54.625720]  [<ffffffff811f14a7>] drm_lastclose+0x44/0x2ad
> [   54.625722]  [<ffffffff811f1ed2>] drm_release+0x5c6/0x609
> [   54.625726]  [<ffffffff810d1275>] fput+0x109/0x1c7
> [   54.625728]  [<ffffffff810ce5e4>] filp_close+0x61/0x6b
> [   54.625731]  [<ffffffff810ce680>] sys_close+0x92/0xd4
> [   54.625734]  [<ffffffff81002a2b>] system_call_fastpath+0x16/0x1b
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/drm_fops.c |    9 ++++-----
>  1 files changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
> index 2ca8df8..6367961 100644
> --- a/drivers/gpu/drm/drm_fops.c
> +++ b/drivers/gpu/drm/drm_fops.c
> @@ -572,16 +572,15 @@ int drm_release(struct inode *inode, struct file *filp)
>        atomic_inc(&dev->counts[_DRM_STAT_CLOSES]);
>        spin_lock(&dev->count_lock);
>        if (!--dev->open_count) {
> +               spin_unlock(&dev->count_lock);
> +
>                if (atomic_read(&dev->ioctl_count)) {
>                        DRM_ERROR("Device busy: %d\n",
>                                  atomic_read(&dev->ioctl_count));
>                        retcode = -EBUSY;
> -                       goto out;
> -               }
> -               retcode = drm_lastclose(dev);
> +               } else
> +                       retcode = drm_lastclose(dev);
>        }
> -out:
> -       spin_unlock(&dev->count_lock);
>        mutex_unlock(&drm_global_mutex);
>
>        return retcode;
> --
> 1.7.1
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
>

[PATCH] drm: Use global_mutex to serialise open/lastclose

[Chris Wilson]

Dave Airlie:
  I might be missing something, but what stops the race with something
  reopening while we are in lastclose now?

The global_mutex which appears to fill this role is only taken inside
the drm_stub_open() and not drm_open() itself. As that mutex appears to
serve no other role, retask it to serialise open/lastclose.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/drm_fops.c |   35 ++++++++++++++++++-----------------
 1 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index 6367961..71bcd1b 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -123,27 +123,30 @@ int drm_open(struct inode *inode, struct file *filp)
 	struct drm_device *dev = NULL;
 	int minor_id = iminor(inode);
 	struct drm_minor *minor;
-	int retcode = 0;
+	int retcode = -ENODEV;
 
+	mutex_lock(&drm_global_mutex);
 	minor = idr_find(&drm_minors_idr, minor_id);
 	if (!minor)
-		return -ENODEV;
+		goto err;
 
 	if (!(dev = minor->dev))
-		return -ENODEV;
+		goto err;
 
 	retcode = drm_open_helper(inode, filp, dev);
-	if (!retcode) {
-		atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
-		spin_lock(&dev->count_lock);
-		if (!dev->open_count++) {
-			spin_unlock(&dev->count_lock);
-			retcode = drm_setup(dev);
-			goto out;
-		}
+	if (retcode)
+		goto err;
+
+	atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
+	spin_lock(&dev->count_lock);
+	if (!dev->open_count++) {
 		spin_unlock(&dev->count_lock);
-	}
-out:
+		retcode = drm_setup(dev);
+	} else
+		spin_unlock(&dev->count_lock);
+err:
+	mutex_unlock(&drm_global_mutex);
+
 	if (!retcode) {
 		mutex_lock(&dev->struct_mutex);
 		if (minor->type == DRM_MINOR_LEGACY) {
@@ -178,7 +181,6 @@ int drm_stub_open(struct inode *inode, struct file *filp)
 
 	DRM_DEBUG("\n");
 
-	mutex_lock(&drm_global_mutex);
 	minor = idr_find(&drm_minors_idr, minor_id);
 	if (!minor)
 		goto out;
@@ -198,8 +200,8 @@ int drm_stub_open(struct inode *inode, struct file *filp)
 	}
 	fops_put(old_fops);
 
+	ret = 0;
 out:
-	mutex_unlock(&drm_global_mutex);
 	return err;
 }
 
@@ -474,8 +476,6 @@ int drm_release(struct inode *inode, struct file *filp)
 	struct drm_device *dev = file_priv->minor->dev;
 	int retcode = 0;
 
-	mutex_lock(&drm_global_mutex);
-
 	DRM_DEBUG("open_count = %d\n", dev->open_count);
 
 	if (dev->driver->preclose)
@@ -569,6 +569,7 @@ int drm_release(struct inode *inode, struct file *filp)
 	 * End inline drm_release
 	 */
 
+	mutex_lock(&drm_global_mutex);
 	atomic_inc(&dev->counts[_DRM_STAT_CLOSES]);
 	spin_lock(&dev->count_lock);
 	if (!--dev->open_count) {
-- 
1.7.1

Re: [PATCH] drm: Use global_mutex to serialise open/lastclose

[Chris Wilson]

On Sun,  8 Aug 2010 09:37:24 +0100, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> Dave Airlie:
>   I might be missing something, but what stops the race with something
>   reopening while we are in lastclose now?
> 
> The global_mutex which appears to fill this role is only taken inside
> the drm_stub_open() and not drm_open() itself. As that mutex appears to
> serve no other role, retask it to serialise open/lastclose.

This patch was just wrong. The ordering is drm_stub_open() -> drm_open()
so open/lastclose are currently serialised using drm_global_mutex.
-- 
Chris Wilson, Intel Open Source Technology Centre

Re: [PATCH] drm: Use global_mutex to serialise open/lastclose

[Thomas Hellstrom]

On 08/08/2010 10:37 AM, Chris Wilson wrote:
> Dave Airlie:
>    I might be missing something, but what stops the race with something
>    reopening while we are in lastclose now?
>
> The global_mutex which appears to fill this role is only taken inside
> the drm_stub_open() and not drm_open() itself. As that mutex appears to
> serve no other role, retask it to serialise open/lastclose.
>    

Hmm.

But, if used this way, drm_global_mutex needs to protect *all* accesses
to dev::open_count, what is count_clock used for? Can't it be removed?

/Thomas


> Signed-off-by: Chris Wilson<chris@chris-wilson.co.uk>
> ---
>   drivers/gpu/drm/drm_fops.c |   35 ++++++++++++++++++-----------------
>   1 files changed, 18 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
> index 6367961..71bcd1b 100644
> --- a/drivers/gpu/drm/drm_fops.c
> +++ b/drivers/gpu/drm/drm_fops.c
> @@ -123,27 +123,30 @@ int drm_open(struct inode *inode, struct file *filp)
>   	struct drm_device *dev = NULL;
>   	int minor_id = iminor(inode);
>   	struct drm_minor *minor;
> -	int retcode = 0;
> +	int retcode = -ENODEV;
>
> +	mutex_lock(&drm_global_mutex);
>   	minor = idr_find(&drm_minors_idr, minor_id);
>   	if (!minor)
> -		return -ENODEV;
> +		goto err;
>
>   	if (!(dev = minor->dev))
> -		return -ENODEV;
> +		goto err;
>
>   	retcode = drm_open_helper(inode, filp, dev);
> -	if (!retcode) {
> -		atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
> -		spin_lock(&dev->count_lock);
> -		if (!dev->open_count++) {
> -			spin_unlock(&dev->count_lock);
> -			retcode = drm_setup(dev);
> -			goto out;
> -		}
> +	if (retcode)
> +		goto err;
> +
> +	atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
> +	spin_lock(&dev->count_lock);
> +	if (!dev->open_count++) {
>   		spin_unlock(&dev->count_lock);
> -	}
> -out:
> +		retcode = drm_setup(dev);
> +	} else
> +		spin_unlock(&dev->count_lock);
> +err:
> +	mutex_unlock(&drm_global_mutex);
> +
>   	if (!retcode) {
>   		mutex_lock(&dev->struct_mutex);
>   		if (minor->type == DRM_MINOR_LEGACY) {
> @@ -178,7 +181,6 @@ int drm_stub_open(struct inode *inode, struct file *filp)
>
>   	DRM_DEBUG("\n");
>
> -	mutex_lock(&drm_global_mutex);
>   	minor = idr_find(&drm_minors_idr, minor_id);
>   	if (!minor)
>   		goto out;
> @@ -198,8 +200,8 @@ int drm_stub_open(struct inode *inode, struct file *filp)
>   	}
>   	fops_put(old_fops);
>
> +	ret = 0;
>   out:
> -	mutex_unlock(&drm_global_mutex);
>   	return err;
>   }
>
> @@ -474,8 +476,6 @@ int drm_release(struct inode *inode, struct file *filp)
>   	struct drm_device *dev = file_priv->minor->dev;
>   	int retcode = 0;
>
> -	mutex_lock(&drm_global_mutex);
> -
>   	DRM_DEBUG("open_count = %d\n", dev->open_count);
>
>   	if (dev->driver->preclose)
> @@ -569,6 +569,7 @@ int drm_release(struct inode *inode, struct file *filp)
>   	 * End inline drm_release
>   	 */
>
> +	mutex_lock(&drm_global_mutex);
>   	atomic_inc(&dev->counts[_DRM_STAT_CLOSES]);
>   	spin_lock(&dev->count_lock);
>   	if (!--dev->open_count) {
>    

[PATCH] drm: Remove count_lock for calling lastclose() after 58474713 (v2)

[Chris Wilson]

When removing of the BKL the locking around lastclose() was rearranged
and resulted in the holding of the open_count spinlock over the call
into drm_lastclose(). The drivers were not ready for this path to be
atomic - it may indeed involve long waits to release old objects and
cleanup the GPU - and so we ended up scheduling whilst atomic.

[   54.625598] BUG: scheduling while atomic: X/3546/0x00000002
[   54.625600] Modules linked in: sco bridge stp llc input_polldev rfcomm bnep l2cap crc16 sch_sfq ipv6 md_mod acpi_cpufreq mperf cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt dm_mod btusb bluetooth usbhid hid zaurus cdc_ether usbnet mii cdc_wdm cdc_acm uvcvideo videodev v4l1_compat v4l2_compat_ioctl32 snd_hda_codec_conexant arc4 pcmcia ecb snd_hda_intel joydev sdhci_pci sdhci snd_hda_codec tpm_tis firewire_ohci mmc_core e1000e uhci_hcd thinkpad_acpi nvram yenta_socket pcmcia_rsrc pcmcia_core tpm wmi sr_mod firewire_core iwlagn ehci_hcd snd_hwdep snd_pcm usbcore tpm_bios thermal led_class snd_timer iwlcore snd soundcore ac snd_page_alloc pcspkr psmouse serio_raw battery sg mac80211 evdev cfg80211 i2c_i801 iTCO_wdt iTCO_vendor_support cdrom processor crc_itu_t rfkill xfs exportfs sd_m
 od crc_t10dif ahci libahci libata scsi_mod [last unloaded: scsi_wait_scan]
[   54.625663] Pid: 3546, comm: X Not tainted 2.6.35-04771-g1787985 #301
[   54.625665] Call Trace:
[   54.625671]  [<ffffffff8102d599>] __schedule_bug+0x57/0x5c
[   54.625675]  [<ffffffff81384141>] schedule+0xe5/0x832
[   54.625679]  [<ffffffff81163e77>] ? put_dec+0x20/0x3c
[   54.625682]  [<ffffffff81384dd4>] schedule_timeout+0x275/0x29f
[   54.625686]  [<ffffffff810455e1>] ? process_timeout+0x0/0xb
[   54.625688]  [<ffffffff81384e17>] schedule_timeout_uninterruptible+0x19/0x1b
[   54.625691]  [<ffffffff81045893>] msleep+0x16/0x1d
[   54.625695]  [<ffffffff812a2e53>] i9xx_crtc_dpms+0x273/0x2ae
[   54.625698]  [<ffffffff812a18be>] intel_crtc_dpms+0x28/0xe7
[   54.625702]  [<ffffffff811ec0fa>] drm_helper_disable_unused_functions+0xf0/0x118
[   54.625705]  [<ffffffff811ecde3>] drm_crtc_helper_set_config+0x644/0x7c8
[   54.625708]  [<ffffffff811f12dd>] ? drm_copy_field+0x40/0x50
[   54.625711]  [<ffffffff811ebca2>] drm_fb_helper_force_kernel_mode+0x3e/0x85
[   54.625713]  [<ffffffff811ebcf2>] drm_fb_helper_restore+0x9/0x24
[   54.625717]  [<ffffffff81290a41>] i915_driver_lastclose+0x2b/0x5c
[   54.625720]  [<ffffffff811f14a7>] drm_lastclose+0x44/0x2ad
[   54.625722]  [<ffffffff811f1ed2>] drm_release+0x5c6/0x609
[   54.625726]  [<ffffffff810d1275>] fput+0x109/0x1c7
[   54.625728]  [<ffffffff810ce5e4>] filp_close+0x61/0x6b
[   54.625731]  [<ffffffff810ce680>] sys_close+0x92/0xd4
[   54.625734]  [<ffffffff81002a2b>] system_call_fastpath+0x16/0x1b

v2: The spinlock is actually superfluous as access to open_count is
entirely serialised by drm_global_mutex and so can be dropped. The
count_lock spinlock instead appears to be used to protect access to
dev->buf_alloc and dev->buf_use.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/drm_fops.c |   16 +++-------------
 1 files changed, 3 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index 2ca8df8..3a652a6 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -135,15 +135,9 @@ int drm_open(struct inode *inode, struct file *filp)
 	retcode = drm_open_helper(inode, filp, dev);
 	if (!retcode) {
 		atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
-		spin_lock(&dev->count_lock);
-		if (!dev->open_count++) {
-			spin_unlock(&dev->count_lock);
+		if (!dev->open_count++)
 			retcode = drm_setup(dev);
-			goto out;
-		}
-		spin_unlock(&dev->count_lock);
 	}
-out:
 	if (!retcode) {
 		mutex_lock(&dev->struct_mutex);
 		if (minor->type == DRM_MINOR_LEGACY) {
@@ -570,18 +564,14 @@ int drm_release(struct inode *inode, struct file *filp)
 	 */
 
 	atomic_inc(&dev->counts[_DRM_STAT_CLOSES]);
-	spin_lock(&dev->count_lock);
 	if (!--dev->open_count) {
 		if (atomic_read(&dev->ioctl_count)) {
 			DRM_ERROR("Device busy: %d\n",
 				  atomic_read(&dev->ioctl_count));
 			retcode = -EBUSY;
-			goto out;
-		}
-		retcode = drm_lastclose(dev);
+		} else
+			retcode = drm_lastclose(dev);
 	}
-out:
-	spin_unlock(&dev->count_lock);
 	mutex_unlock(&drm_global_mutex);
 
 	return retcode;
-- 
1.7.1