[PATCH] drm/radeon: add an exclusive lock for GPU reset

[Jerome Glisse]

On Mon, Jul 2, 2012 at 11:39 AM,  <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.
>
> Signed-off-by: Jerome Glisse <jglisse at redhat.com>

Wrong patch sorry resending

> ---
>  drivers/gpu/drm/radeon/radeon.h        |    1 +
>  drivers/gpu/drm/radeon/radeon_cs.c     |    5 +++++
>  drivers/gpu/drm/radeon/radeon_device.c |    2 ++
>  drivers/gpu/drm/radeon/radeon_gem.c    |    7 +++++++
>  4 files changed, 15 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..c8fdb40 100644
> --- a/drivers/gpu/drm/radeon/radeon_device.c
> +++ b/drivers/gpu/drm/radeon/radeon_device.c
> @@ -988,6 +988,7 @@ 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 +1008,7 @@ 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..f99db63 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;
> @@ -255,9 +260,11 @@ int radeon_gem_set_domain_ioctl(struct drm_device *dev, void *data,
>        }
>        robj = gem_to_radeon_bo(gobj);
>
> +       down_read(&rdev->exclusive_lock);
>        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;
>  }
> --
> 1.7.10.2
>