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); }