On 02.07.2012 18:45, j.glisse at gmail.com wrote:
> From: Jerome Glisse <jglisse at redhat.com>
>
> GPU reset need to be exclusive, one happening at a time. For this
> add a rw semaphore so that any path that trigger GPU activities
> have to take the semaphore as a reader thus allowing concurency.
>
> The GPU reset path take the semaphore as a writer ensuring that
> no concurrent reset take place.
>
> v2: init rw semaphore
>
> Signed-off-by: Jerome Glisse <jglisse at redhat.com>
Maybe we don't want to call it "exclusive_lock", cause a lock is always
somehow exclusive. Anyway it's:
Reviewed-by: Christian K?nig <christian.koenig at amd.com>
> ---
> drivers/gpu/drm/radeon/radeon.h | 1 +
> drivers/gpu/drm/radeon/radeon_cs.c | 5 +++++
> drivers/gpu/drm/radeon/radeon_device.c | 3 +++
> drivers/gpu/drm/radeon/radeon_gem.c | 8 ++++++++
> 4 files changed, 17 insertions(+)
>
> diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
> index 77b4519b..29d6986 100644
> --- a/drivers/gpu/drm/radeon/radeon.h
> +++ b/drivers/gpu/drm/radeon/radeon.h
> @@ -1446,6 +1446,7 @@ struct radeon_device {
> struct device *dev;
> struct drm_device *ddev;
> struct pci_dev *pdev;
> + struct rw_semaphore exclusive_lock;
> /* ASIC */
> union radeon_asic_config config;
> enum radeon_family family;
> diff --git a/drivers/gpu/drm/radeon/radeon_cs.c
> b/drivers/gpu/drm/radeon/radeon_cs.c
> index f1b7527..7ee6491 100644
> --- a/drivers/gpu/drm/radeon/radeon_cs.c
> +++ b/drivers/gpu/drm/radeon/radeon_cs.c
> @@ -499,7 +499,9 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data,
> struct drm_file *filp)
> struct radeon_cs_parser parser;
> int r;
>
> + down_read(&rdev->exclusive_lock);
> if (!rdev->accel_working) {
> + up_read(&rdev->exclusive_lock);
> return -EBUSY;
> }
> /* initialize parser */
> @@ -512,6 +514,7 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data,
> struct drm_file *filp)
> if (r) {
> DRM_ERROR("Failed to initialize parser !\n");
> radeon_cs_parser_fini(&parser, r);
> + up_read(&rdev->exclusive_lock);
> r = radeon_cs_handle_lockup(rdev, r);
> return r;
> }
> @@ -520,6 +523,7 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data,
> struct drm_file *filp)
> if (r != -ERESTARTSYS)
> DRM_ERROR("Failed to parse relocation %d!\n", r);
> radeon_cs_parser_fini(&parser, r);
> + up_read(&rdev->exclusive_lock);
> r = radeon_cs_handle_lockup(rdev, r);
> return r;
> }
> @@ -533,6 +537,7 @@ int radeon_cs_ioctl(struct drm_device *dev, void *data,
> struct drm_file *filp)
> }
> out:
> radeon_cs_parser_fini(&parser, r);
> + up_read(&rdev->exclusive_lock);
> r = radeon_cs_handle_lockup(rdev, r);
> return r;
> }
> diff --git a/drivers/gpu/drm/radeon/radeon_device.c
> b/drivers/gpu/drm/radeon/radeon_device.c
> index f654ba8..254fdb4 100644
> --- a/drivers/gpu/drm/radeon/radeon_device.c
> +++ b/drivers/gpu/drm/radeon/radeon_device.c
> @@ -734,6 +734,7 @@ int radeon_device_init(struct radeon_device *rdev,
> mutex_init(&rdev->gem.mutex);
> mutex_init(&rdev->pm.mutex);
> init_rwsem(&rdev->pm.mclk_lock);
> + init_rwsem(&rdev->exclusive_lock);
> init_waitqueue_head(&rdev->irq.vblank_queue);
> init_waitqueue_head(&rdev->irq.idle_queue);
> r = radeon_gem_init(rdev);
> @@ -988,6 +989,7 @@ int radeon_gpu_reset(struct radeon_device *rdev)
> int r;
> int resched;
>
> + down_write(&rdev->exclusive_lock);
> radeon_save_bios_scratch_regs(rdev);
> /* block TTM */
> resched = ttm_bo_lock_delayed_workqueue(&rdev->mman.bdev);
> @@ -1007,6 +1009,7 @@ int radeon_gpu_reset(struct radeon_device *rdev)
> dev_info(rdev->dev, "GPU reset failed\n");
> }
>
> + up_write(&rdev->exclusive_lock);
> return r;
> }
>
> diff --git a/drivers/gpu/drm/radeon/radeon_gem.c
> b/drivers/gpu/drm/radeon/radeon_gem.c
> index d9b0809..b0be9c4 100644
> --- a/drivers/gpu/drm/radeon/radeon_gem.c
> +++ b/drivers/gpu/drm/radeon/radeon_gem.c
> @@ -215,12 +215,14 @@ int radeon_gem_create_ioctl(struct drm_device *dev,
> void *data,
> uint32_t handle;
> int r;
>
> + down_read(&rdev->exclusive_lock);
> /* create a gem object to contain this object in */
> args->size = roundup(args->size, PAGE_SIZE);
> r = radeon_gem_object_create(rdev, args->size, args->alignment,
> args->initial_domain, false,
> false, &gobj);
> if (r) {
> + up_read(&rdev->exclusive_lock);
> r = radeon_gem_handle_lockup(rdev, r);
> return r;
> }
> @@ -228,10 +230,12 @@ int radeon_gem_create_ioctl(struct drm_device *dev,
> void *data,
> /* drop reference from allocate - handle holds it now */
> drm_gem_object_unreference_unlocked(gobj);
> if (r) {
> + up_read(&rdev->exclusive_lock);
> r = radeon_gem_handle_lockup(rdev, r);
> return r;
> }
> args->handle = handle;
> + up_read(&rdev->exclusive_lock);
> return 0;
> }
>
> @@ -240,6 +244,7 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev,
> void *data,
> {
> /* transition the BO to a domain -
> * just validate the BO into a certain domain */
> + struct radeon_device *rdev = dev->dev_private;
> struct drm_radeon_gem_set_domain *args = data;
> struct drm_gem_object *gobj;
> struct radeon_bo *robj;
> @@ -247,10 +252,12 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev,
> void *data,
>
> /* for now if someone requests domain CPU -
> * just make sure the buffer is finished with */
> + down_read(&rdev->exclusive_lock);
>
> /* just do a BO wait for now */
> gobj = drm_gem_object_lookup(dev, filp, args->handle);
> if (gobj == NULL) {
> + up_read(&rdev->exclusive_lock);
> return -ENOENT;
> }
> robj = gem_to_radeon_bo(gobj);
> @@ -258,6 +265,7 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev,
> void *data,
> r = radeon_gem_set_domain(gobj, args->read_domains, args->write_domain);
>
> drm_gem_object_unreference_unlocked(gobj);
> + up_read(&rdev->exclusive_lock);
> r = radeon_gem_handle_lockup(robj->rdev, r);
> return r;
> }
