On Tue, Mar 27, 2018 at 10:23:54AM +0200, Daniel Vetter wrote:
It's only used to protect our page list, and only when we know we have a full reference. This means none of these code paths can ever race with the final unref, and hence we do not need dev->struct_mutex serialization and can simply switch to our own locking.
For more context the only magic the locked gem_free_object provides is that it prevents concurrent final unref (and destruction) of gem objects while anyone is holding dev->struct_mutex. This was used by i915 (and other drivers) to implement eviction handling with less headaches.
Signed-off-by: Daniel Vetter daniel.vetter@intel.com
Reviewed-by: Sean Paul seanpaul@chromium.org
Cc: Dave Airlie airlied@redhat.com
drivers/gpu/drm/udl/udl_dmabuf.c | 5 +++-- drivers/gpu/drm/udl/udl_drv.c | 2 +- drivers/gpu/drm/udl/udl_drv.h | 2 ++ drivers/gpu/drm/udl/udl_gem.c | 5 +++-- drivers/gpu/drm/udl/udl_main.c | 2 ++ 5 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/udl/udl_dmabuf.c b/drivers/gpu/drm/udl/udl_dmabuf.c index 2867ed155ff6..0a20695eb120 100644 --- a/drivers/gpu/drm/udl/udl_dmabuf.c +++ b/drivers/gpu/drm/udl/udl_dmabuf.c @@ -76,6 +76,7 @@ static struct sg_table *udl_map_dma_buf(struct dma_buf_attachment *attach, struct udl_drm_dmabuf_attachment *udl_attach = attach->priv; struct udl_gem_object *obj = to_udl_bo(attach->dmabuf->priv); struct drm_device *dev = obj->base.dev;
- struct udl_device *udl = dev->dev_private; struct scatterlist *rd, *wr; struct sg_table *sgt = NULL; unsigned int i;
@@ -112,7 +113,7 @@ static struct sg_table *udl_map_dma_buf(struct dma_buf_attachment *attach, return ERR_PTR(-ENOMEM); }
- mutex_lock(&dev->struct_mutex);
mutex_lock(&udl->gem_lock);
rd = obj->sg->sgl; wr = sgt->sgl;
@@ -137,7 +138,7 @@ static struct sg_table *udl_map_dma_buf(struct dma_buf_attachment *attach, attach->priv = udl_attach;
err_unlock:
- mutex_unlock(&dev->struct_mutex);
- mutex_unlock(&udl->gem_lock); return sgt;
}
diff --git a/drivers/gpu/drm/udl/udl_drv.c b/drivers/gpu/drm/udl/udl_drv.c index 3c45a3064726..9ef515df724b 100644 --- a/drivers/gpu/drm/udl/udl_drv.c +++ b/drivers/gpu/drm/udl/udl_drv.c @@ -53,7 +53,7 @@ static struct drm_driver driver = { .unload = udl_driver_unload,
/* gem hooks */
- .gem_free_object = udl_gem_free_object,
.gem_free_object_unlocked = udl_gem_free_object, .gem_vm_ops = &udl_gem_vm_ops,
.dumb_create = udl_dumb_create,
diff --git a/drivers/gpu/drm/udl/udl_drv.h b/drivers/gpu/drm/udl/udl_drv.h index 2a75ab80527a..55c0cc309198 100644 --- a/drivers/gpu/drm/udl/udl_drv.h +++ b/drivers/gpu/drm/udl/udl_drv.h @@ -54,6 +54,8 @@ struct udl_device { struct usb_device *udev; struct drm_crtc *crtc;
struct mutex gem_lock;
int sku_pixel_limit;
struct urb_list urbs;
diff --git a/drivers/gpu/drm/udl/udl_gem.c b/drivers/gpu/drm/udl/udl_gem.c index dee6bd9a3dd1..9a15cce22cce 100644 --- a/drivers/gpu/drm/udl/udl_gem.c +++ b/drivers/gpu/drm/udl/udl_gem.c @@ -214,9 +214,10 @@ int udl_gem_mmap(struct drm_file *file, struct drm_device *dev, { struct udl_gem_object *gobj; struct drm_gem_object *obj;
- struct udl_device *udl = dev->dev_private; int ret = 0;
- mutex_lock(&dev->struct_mutex);
- mutex_lock(&udl->gem_lock); obj = drm_gem_object_lookup(file, handle); if (obj == NULL) { ret = -ENOENT;
@@ -236,6 +237,6 @@ int udl_gem_mmap(struct drm_file *file, struct drm_device *dev, out: drm_gem_object_put(&gobj->base); unlock:
- mutex_unlock(&dev->struct_mutex);
- mutex_unlock(&udl->gem_lock); return ret;
} diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c index f1ec4528a73e..d518de8f496b 100644 --- a/drivers/gpu/drm/udl/udl_main.c +++ b/drivers/gpu/drm/udl/udl_main.c @@ -324,6 +324,8 @@ int udl_driver_load(struct drm_device *dev, unsigned long flags) udl->ddev = dev; dev->dev_private = udl;
- mutex_init(&udl->gem_lock);
- if (!udl_parse_vendor_descriptor(dev, udl->udev)) { ret = -ENODEV; DRM_ERROR("firmware not recognized. Assume incompatible device\n");
-- 2.16.2
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