drm/radeon/kms: Bailout of blit if error happen & protect with mutex V3

If an error happen in r600_blit_prepare_copy report it rather
than WARNING and keeping execution. For instance if ib allocation
failed we did just warn about but then latter tried to access
NULL ib ptr causing oops. This patch also protect r600_copy_blit
with a mutex as otherwise one process might overwrite blit temporary
data with new one possibly leading to GPU lockup.

Should partialy or totaly fix:
https://bugzilla.redhat.com/show_bug.cgi?id=553279

V2 failing blit initialization is not fatal, fallback to memcpy when
this happen
V3 init blit before startup as we pin in startup, remove duplicate
code (this one was actualy tested unlike V2)
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/r600.c

@@ -1788,23 +1788,24 @@ void r600_fence_ring_emit(struct radeon_device *rdev,
 	radeon_ring_write(rdev, RB_INT_STAT);
 }
 
-int r600_copy_dma(struct radeon_device *rdev,
-		  uint64_t src_offset,
-		  uint64_t dst_offset,
-		  unsigned num_pages,
-		  struct radeon_fence *fence)
-{
-	/* FIXME: implement */
-	return 0;
-}
-
 int r600_copy_blit(struct radeon_device *rdev,
 		   uint64_t src_offset, uint64_t dst_offset,
 		   unsigned num_pages, struct radeon_fence *fence)
 {
-	r600_blit_prepare_copy(rdev, num_pages * RADEON_GPU_PAGE_SIZE);
+	int r;
+
+	mutex_lock(&rdev->r600_blit.mutex);
+	rdev->r600_blit.vb_ib = NULL;
+	r = r600_blit_prepare_copy(rdev, num_pages * RADEON_GPU_PAGE_SIZE);
+	if (r) {
+		if (rdev->r600_blit.vb_ib)
+			radeon_ib_free(rdev, &rdev->r600_blit.vb_ib);
+		mutex_unlock(&rdev->r600_blit.mutex);
+		return r;
+	}
 	r600_kms_blit_copy(rdev, src_offset, dst_offset, num_pages * RADEON_GPU_PAGE_SIZE);
 	r600_blit_done_copy(rdev, fence);
+	mutex_unlock(&rdev->r600_blit.mutex);
 	return 0;
 }
 
@@ -1860,15 +1861,8 @@ int r600_startup(struct radeon_device *rdev)
 			return r;
 	}
 	r600_gpu_init(rdev);
-
-	if (!rdev->r600_blit.shader_obj) {
-		r = r600_blit_init(rdev);
-		if (r) {
-			DRM_ERROR("radeon: failed blitter (%d).\n", r);
-			return r;
-		}
-	}
-
+	/* pin copy shader into vram */
+	if (rdev->r600_blit.shader_obj) {
 		r = radeon_bo_reserve(rdev->r600_blit.shader_obj, false);
 		if (unlikely(r != 0))
 			return r;
@@ -1879,7 +1873,7 @@ int r600_startup(struct radeon_device *rdev)
 			dev_err(rdev->dev, "(%d) pin blit object failed\n", r);
 			return r;
 		}
-
+	}
 	/* Enable IRQ */
 	r = r600_irq_init(rdev);
 	if (r) {
@@ -2051,6 +2045,12 @@ int r600_init(struct radeon_device *rdev)
 	r = r600_pcie_gart_init(rdev);
 	if (r)
 		return r;
+	r = r600_blit_init(rdev);
+	if (r) {
+		r600_blit_fini(rdev);
+		rdev->asic->copy = NULL;
+		dev_warn(rdev->dev, "failed blitter (%d) falling back to memcpy\n", r);
+	}
 
 	rdev->accel_working = true;
 	r = r600_startup(rdev);

drivers/gpu/drm/radeon/r600_blit_kms.c

@@ -449,6 +449,7 @@ int r600_blit_init(struct radeon_device *rdev)
 	u32 packet2s[16];
 	int num_packet2s = 0;
 
+	mutex_init(&rdev->r600_blit.mutex);
 	rdev->r600_blit.state_offset = 0;
 
 	if (rdev->family >= CHIP_RV770)
@@ -557,7 +558,8 @@ int r600_blit_prepare_copy(struct radeon_device *rdev, int size_bytes)
 	int dwords_per_loop = 76, num_loops;
 
 	r = r600_vb_ib_get(rdev);
-	WARN_ON(r);
+	if (r)
+		return r;
 
 	/* set_render_target emits 2 extra dwords on rv6xx */
 	if (rdev->family > CHIP_R600 && rdev->family < CHIP_RV770)
@@ -583,7 +585,8 @@ int r600_blit_prepare_copy(struct radeon_device *rdev, int size_bytes)
 	ring_size += 5; /* done copy */
 	ring_size += 7; /* fence emit for done copy */
 	r = radeon_ring_lock(rdev, ring_size);
-	WARN_ON(r);
+	if (r)
+		return r;
 
 	set_default_state(rdev); /* 14 */
 	set_shaders(rdev); /* 26 */

drivers/gpu/drm/radeon/radeon.h

@@ -416,6 +416,7 @@ struct r600_ih {
 };
 
 struct r600_blit {
+	struct mutex		mutex;
 	struct radeon_bo	*shader_obj;
 	u64 shader_gpu_addr;
 	u32 vs_offset, ps_offset;

drivers/gpu/drm/radeon/rv770.c

@@ -887,15 +887,8 @@ static int rv770_startup(struct radeon_device *rdev)
 			return r;
 	}
 	rv770_gpu_init(rdev);
-
-	if (!rdev->r600_blit.shader_obj) {
-		r = r600_blit_init(rdev);
-		if (r) {
-			DRM_ERROR("radeon: failed blitter (%d).\n", r);
-			return r;
-		}
-	}
-
+	/* pin copy shader into vram */
+	if (rdev->r600_blit.shader_obj) {
 		r = radeon_bo_reserve(rdev->r600_blit.shader_obj, false);
 		if (unlikely(r != 0))
 			return r;
@@ -906,7 +899,7 @@ static int rv770_startup(struct radeon_device *rdev)
 			DRM_ERROR("failed to pin blit object %d\n", r);
 			return r;
 		}
-
+	}
 	/* Enable IRQ */
 	r = r600_irq_init(rdev);
 	if (r) {
@@ -1062,6 +1055,12 @@ int rv770_init(struct radeon_device *rdev)
 	r = r600_pcie_gart_init(rdev);
 	if (r)
 		return r;
+	r = r600_blit_init(rdev);
+	if (r) {
+		r600_blit_fini(rdev);
+		rdev->asic->copy = NULL;
+		dev_warn(rdev->dev, "failed blitter (%d) falling back to memcpy\n", r);
+	}
 
 	rdev->accel_working = true;
 	r = rv770_startup(rdev);