[PATCH 2/2] drm: i810/i830: kill BKL, mark as BROKEN_ON_SMP

Arnd Bergmann arnd at arndb.de
Wed Sep 29 08:47:59 PDT 2010


The i810 and i830 drivers are the only hardware drivers that
still use the BKL without anyone volunteering to fix them.

The hardware is rather old and typically used on non-SMP
systems. Mark them as BROKEN_ON_SMP and remove the BKL
now so that people can still use the driver once the BKL
is entirely gone.

I could not actually find a reason why the BKL is required
here, the same operations that need it also seem to take
the mmap_sem. If anyone can prove that it's really not
necessary, please remove the BROKEN_ON_SMP requirement.

Signed-off-by: Arnd Bergmann <arnd at arndb.de>
---
 drivers/gpu/drm/Kconfig         |    6 ++----
 drivers/gpu/drm/i810/i810_dma.c |   18 +-----------------
 drivers/gpu/drm/i810/i810_drv.c |    2 +-
 drivers/gpu/drm/i830/i830_dma.c |   18 +-----------------
 drivers/gpu/drm/i830/i830_drv.c |    2 +-
 5 files changed, 6 insertions(+), 40 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index b755301..fe4b94f 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -73,8 +73,7 @@ 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
+	depends on DRM && AGP && AGP_INTEL && BROKEN_ON_SMP
 	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
@@ -87,8 +86,7 @@ choice
 
 config DRM_I830
 	tristate "i830 driver"
-	# BKL usage in order to avoid AB-BA deadlocks, may become BROKEN_ON_SMP
-	depends on BKL
+	depends on BROKEN_ON_SMP
 	help
 	  Choose this option if you have a system that has Intel 830M, 845G,
 	  852GM, 855GM or 865G integrated graphics.  If M is selected, the
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..7544ece 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,
diff --git a/drivers/gpu/drm/i830/i830_dma.c b/drivers/gpu/drm/i830/i830_dma.c
index ca6f31f..0320030 100644
--- a/drivers/gpu/drm/i830/i830_dma.c
+++ b/drivers/gpu/drm/i830/i830_dma.c
@@ -36,7 +36,6 @@
 #include "i830_drm.h"
 #include "i830_drv.h"
 #include <linux/interrupt.h>	/* For task queue support */
-#include <linux/smp_lock.h>
 #include <linux/pagemap.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
@@ -96,7 +95,6 @@ static int i830_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
 	struct drm_buf *buf;
 	drm_i830_buf_priv_t *buf_priv;
 
-	lock_kernel();
 	dev = priv->minor->dev;
 	dev_priv = dev->dev_private;
 	buf = dev_priv->mmap_buffer;
@@ -106,7 +104,6 @@ static int i830_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
 	vma->vm_file = filp;
 
 	buf_priv->currently_mapped = I830_BUF_MAPPED;
-	unlock_kernel();
 
 	if (io_remap_pfn_range(vma, vma->vm_start,
 			       vma->vm_pgoff,
@@ -118,7 +115,7 @@ static int i830_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
 static const struct file_operations i830_buffer_fops = {
 	.open = drm_open,
 	.release = drm_release,
-	.unlocked_ioctl = i830_ioctl,
+	.unlocked_ioctl = drm_ioctl,
 	.mmap = i830_mmap_buffers,
 	.fasync = drm_fasync,
 	.llseek = noop_llseek,
@@ -1511,19 +1508,6 @@ int i830_driver_dma_quiescent(struct drm_device *dev)
 	return 0;
 }
 
-/*
- * call the drm_ioctl under the big kernel lock because
- * to lock against the i830_mmap_buffers function.
- */
-long i830_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 i830_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(I830_INIT, i830_dma_init, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY|DRM_UNLOCKED),
 	DRM_IOCTL_DEF_DRV(I830_VERTEX, i830_dma_vertex, DRM_AUTH|DRM_UNLOCKED),
diff --git a/drivers/gpu/drm/i830/i830_drv.c b/drivers/gpu/drm/i830/i830_drv.c
index f655ab7..38378c9 100644
--- a/drivers/gpu/drm/i830/i830_drv.c
+++ b/drivers/gpu/drm/i830/i830_drv.c
@@ -68,7 +68,7 @@ static struct drm_driver driver = {
 		 .owner = THIS_MODULE,
 		 .open = drm_open,
 		 .release = drm_release,
-		 .unlocked_ioctl = i830_ioctl,
+		 .unlocked_ioctl = drm_ioctl,
 		 .mmap = drm_mmap,
 		 .poll = drm_poll,
 		 .fasync = drm_fasync,
-- 
1.7.1



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