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Commit ad778f89 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Export our request as a dma-buf fence on the reservation object 



If the GEM objects being rendered with in this request have been
exported via dma-buf to a third party, hook ourselves into the dma-buf
reservation object so that the third party can serialise with our
rendering via the dma-buf fences.

Testcase: igt/prime_busy
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1470324762-2545-26-git-send-email-chris@chris-wilson.co.uk
parent 0eafec6d

drivers/gpu/drm/i915/i915_gem_dmabuf.c

+55 −3
Original line number Diff line number Diff line
@@ -23,9 +23,13 @@ 
 * Authors:

 *	Dave Airlie <airlied@redhat.com>

 */



#include <linux/dma-buf.h>

#include <linux/reservation.h>



#include <drm/drmP.h>



#include "i915_drv.h"

#include <linux/dma-buf.h>



static struct drm_i915_gem_object *dma_buf_to_obj(struct dma_buf *buf)

{
@@ -218,25 +222,73 @@ static const struct dma_buf_ops i915_dmabuf_ops = { 
	.end_cpu_access = i915_gem_end_cpu_access,

};



static void export_fences(struct drm_i915_gem_object *obj,

			  struct dma_buf *dma_buf)

{

	struct reservation_object *resv = dma_buf->resv;

	struct drm_i915_gem_request *req;

	unsigned long active;

	int idx;



	active = __I915_BO_ACTIVE(obj);

	if (!active)

		return;



	/* Serialise with execbuf to prevent concurrent fence-loops */

	mutex_lock(&obj->base.dev->struct_mutex);



	/* Mark the object for future fences before racily adding old fences */

	obj->base.dma_buf = dma_buf;



	ww_mutex_lock(&resv->lock, NULL);



	for_each_active(active, idx) {

		req = i915_gem_active_get(&obj->last_read[idx],

					  &obj->base.dev->struct_mutex);

		if (!req)

			continue;



		if (reservation_object_reserve_shared(resv) == 0)

			reservation_object_add_shared_fence(resv, &req->fence);



		i915_gem_request_put(req);

	}



	req = i915_gem_active_get(&obj->last_write,

				  &obj->base.dev->struct_mutex);

	if (req) {

		reservation_object_add_excl_fence(resv, &req->fence);

		i915_gem_request_put(req);

	}



	ww_mutex_unlock(&resv->lock);

	mutex_unlock(&obj->base.dev->struct_mutex);

}



struct dma_buf *i915_gem_prime_export(struct drm_device *dev,

				      struct drm_gem_object *gem_obj, int flags)

{

	struct drm_i915_gem_object *obj = to_intel_bo(gem_obj);

	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);

	struct dma_buf *dma_buf;



	exp_info.ops = &i915_dmabuf_ops;

	exp_info.size = gem_obj->size;

	exp_info.flags = flags;

	exp_info.priv = gem_obj;





	if (obj->ops->dmabuf_export) {

		int ret = obj->ops->dmabuf_export(obj);

		if (ret)

			return ERR_PTR(ret);

	}



	return dma_buf_export(&exp_info);

	dma_buf = dma_buf_export(&exp_info);

	if (IS_ERR(dma_buf))

		return dma_buf;



	export_fences(obj, dma_buf);

	return dma_buf;

}



static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)

drivers/gpu/drm/i915/i915_gem_execbuffer.c

+29 −2
Original line number Diff line number Diff line
@@ -26,14 +26,18 @@ 
 *

 */



#include <linux/dma_remapping.h>

#include <linux/reservation.h>

#include <linux/uaccess.h>



#include <drm/drmP.h>

#include <drm/i915_drm.h>



#include "i915_drv.h"

#include "i915_gem_dmabuf.h"

#include "i915_trace.h"

#include "intel_drv.h"

#include "intel_frontbuffer.h"

#include <linux/dma_remapping.h>

#include <linux/uaccess.h>



#define  __EXEC_OBJECT_HAS_PIN		(1<<31)

#define  __EXEC_OBJECT_HAS_FENCE	(1<<30)
@@ -1205,6 +1209,28 @@ void i915_vma_move_to_active(struct i915_vma *vma, 
	list_move_tail(&vma->vm_link, &vma->vm->active_list);

}



static void eb_export_fence(struct drm_i915_gem_object *obj,

			    struct drm_i915_gem_request *req,

			    unsigned int flags)

{

	struct reservation_object *resv;



	resv = i915_gem_object_get_dmabuf_resv(obj);

	if (!resv)

		return;



	/* Ignore errors from failing to allocate the new fence, we can't

	 * handle an error right now. Worst case should be missed

	 * synchronisation leading to rendering corruption.

	 */

	ww_mutex_lock(&resv->lock, NULL);

	if (flags & EXEC_OBJECT_WRITE)

		reservation_object_add_excl_fence(resv, &req->fence);

	else if (reservation_object_reserve_shared(resv) == 0)

		reservation_object_add_shared_fence(resv, &req->fence);

	ww_mutex_unlock(&resv->lock);

}



static void

i915_gem_execbuffer_move_to_active(struct list_head *vmas,

				   struct drm_i915_gem_request *req)
@@ -1224,6 +1250,7 @@ i915_gem_execbuffer_move_to_active(struct list_head *vmas, 
		obj->base.read_domains = obj->base.pending_read_domains;



		i915_vma_move_to_active(vma, req, vma->exec_entry->flags);

		eb_export_fence(obj, req, vma->exec_entry->flags);

		trace_i915_gem_object_change_domain(obj, old_read, old_write);

	}

}