drm/i810: remove the BKL

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: dri-devel@lists.freedesktop.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

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),