Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit ae358dac authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/udl: Get rid of dev->struct_mutex usage 



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: default avatarDaniel Vetter <daniel.vetter@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Reviewed-by: default avatarSean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180327082356.24516-3-daniel.vetter@ffwll.ch
parent fcb1e57f

drivers/gpu/drm/udl/udl_dmabuf.c

+3 −2
Original line number Original line Diff line number Diff line
@@ -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_drm_dmabuf_attachment *udl_attach = attach->priv;

	struct udl_gem_object *obj = to_udl_bo(attach->dmabuf->priv);

	struct udl_gem_object *obj = to_udl_bo(attach->dmabuf->priv);

	struct drm_device *dev = obj->base.dev;

	struct drm_device *dev = obj->base.dev;

	struct udl_device *udl = dev->dev_private;

	struct scatterlist *rd, *wr;

	struct scatterlist *rd, *wr;

	struct sg_table *sgt = NULL;

	struct sg_table *sgt = NULL;

	unsigned int i;

	unsigned int i;
@@ -112,7 +113,7 @@ static struct sg_table *udl_map_dma_buf(struct dma_buf_attachment *attach, 
		return ERR_PTR(-ENOMEM);

		return ERR_PTR(-ENOMEM);

	}

	}





	mutex_lock(&dev->struct_mutex);

	mutex_lock(&udl->gem_lock);





	rd = obj->sg->sgl;

	rd = obj->sg->sgl;

	wr = sgt->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;

	attach->priv = udl_attach;





err_unlock:

err_unlock:

	mutex_unlock(&dev->struct_mutex);

	mutex_unlock(&udl->gem_lock);

	return sgt;

	return sgt;

}

}

drivers/gpu/drm/udl/udl_drv.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -53,7 +53,7 @@ static struct drm_driver driver = { 
	.unload = udl_driver_unload,

	.unload = udl_driver_unload,





	/* gem hooks */

	/* gem hooks */

	.gem_free_object = udl_gem_free_object,

	.gem_free_object_unlocked = udl_gem_free_object,

	.gem_vm_ops = &udl_gem_vm_ops,

	.gem_vm_ops = &udl_gem_vm_ops,





	.dumb_create = udl_dumb_create,

	.dumb_create = udl_dumb_create,

drivers/gpu/drm/udl/udl_drv.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -54,6 +54,8 @@ struct udl_device { 
	struct usb_device *udev;

	struct usb_device *udev;

	struct drm_crtc *crtc;

	struct drm_crtc *crtc;





	struct mutex gem_lock;



	int sku_pixel_limit;

	int sku_pixel_limit;





	struct urb_list urbs;

	struct urb_list urbs;

drivers/gpu/drm/udl/udl_gem.c

+3 −2
Original line number Original line Diff line number Diff line
@@ -214,9 +214,10 @@ int udl_gem_mmap(struct drm_file *file, struct drm_device *dev, 
{

{

	struct udl_gem_object *gobj;

	struct udl_gem_object *gobj;

	struct drm_gem_object *obj;

	struct drm_gem_object *obj;

	struct udl_device *udl = dev->dev_private;

	int ret = 0;

	int ret = 0;





	mutex_lock(&dev->struct_mutex);

	mutex_lock(&udl->gem_lock);

	obj = drm_gem_object_lookup(file, handle);

	obj = drm_gem_object_lookup(file, handle);

	if (obj == NULL) {

	if (obj == NULL) {

		ret = -ENOENT;

		ret = -ENOENT;
@@ -236,6 +237,6 @@ int udl_gem_mmap(struct drm_file *file, struct drm_device *dev, 
out:

out:

	drm_gem_object_put(&gobj->base);

	drm_gem_object_put(&gobj->base);

unlock:

unlock:

	mutex_unlock(&dev->struct_mutex);

	mutex_unlock(&udl->gem_lock);

	return ret;

	return ret;

}
 
}

drivers/gpu/drm/udl/udl_main.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -324,6 +324,8 @@ int udl_driver_load(struct drm_device *dev, unsigned long flags) 
	udl->ddev = dev;

	udl->ddev = dev;

	dev->dev_private = udl;

	dev->dev_private = udl;





	mutex_init(&udl->gem_lock);



	if (!udl_parse_vendor_descriptor(dev, udl->udev)) {

	if (!udl_parse_vendor_descriptor(dev, udl->udev)) {

		ret = -ENODEV;

		ret = -ENODEV;

		DRM_ERROR("firmware not recognized. Assume incompatible device\n");

		DRM_ERROR("firmware not recognized. Assume incompatible device\n");