Attachment 692871 Details for Bug 906296 – Don't alloc while holding spinlock

[patch] Don't alloc while holding spinlock

0001-drm-ttm-avoid-allocation-memory-while-spinlock-is-he.patch (text/plain), 2.85 KB, created by Jérôme Glisse on 2013-02-04 16:33:35 UTC

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Creator: Jérôme Glisse

Created: 2013-02-04 16:33:35 UTC

Size: 2.85 KB

patch

obsolete

>From 39c6cefe371a4adc5e8ee446dc78a4e01c3d1a24 Mon Sep 17 00:00:00 2001
>From: Jerome Glisse <jglisse@redhat.com>
>Date: Mon, 4 Feb 2013 11:27:02 -0500
>Subject: [PATCH] drm/ttm: avoid allocation memory while spinlock is held
>
>We need to take reference on the sync object while holding the
>fence spinlock but at the same time we don't want to allocate
>memory while holding the spinlock. This patch make sure we
>enforce both of this constraint.
>
>Fix https://bugzilla.redhat.com/show_bug.cgi?id=906296
>
>Signed-off-by: Jerome Glisse <jglisse@redhat.com>
>---
> drivers/gpu/drm/ttm/ttm_bo_util.c |   16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
>diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
>index 44420fc..77799a5 100644
>--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
>+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
>@@ -413,6 +413,8 @@ static void ttm_transfered_destroy(struct ttm_buffer_object *bo)
>  * @bo: A pointer to a struct ttm_buffer_object.
>  * @new_obj: A pointer to a pointer to a newly created ttm_buffer_object,
>  * holding the data of @bo with the old placement.
>+ * @sync_obj: the sync object caller is responsible to take a reference on
>+ * behalf of this function
>  *
>  * This is a utility function that may be called after an accelerated move
>  * has been scheduled. A new buffer object is created as a placeholder for
>@@ -423,7 +425,8 @@ static void ttm_transfered_destroy(struct ttm_buffer_object *bo)
>  */
> 
> static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
>-				      struct ttm_buffer_object **new_obj)
>+				      struct ttm_buffer_object **new_obj,
>+				      void sync_obj)
> {
> 	struct ttm_buffer_object *fbo;
> 	struct ttm_bo_device *bdev = bo->bdev;
>@@ -448,7 +451,8 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
> 	fbo->vm_node = NULL;
> 	atomic_set(&fbo->cpu_writers, 0);
> 
>-	fbo->sync_obj = driver->sync_obj_ref(bo->sync_obj);
>+	/* reference on sync obj is taken by the caller of this function */
>+	fbo->sync_obj = sync_obj;
> 	kref_init(&fbo->list_kref);
> 	kref_init(&fbo->kref);
> 	fbo->destroy = &ttm_transfered_destroy;
>@@ -652,6 +656,8 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
> 		}
> 		ttm_bo_free_old_node(bo);
> 	} else {
>+		void *sync_obj;
>+
> 		/**
> 		 * This should help pipeline ordinary buffer moves.
> 		 *
>@@ -662,12 +668,14 @@ int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
> 
> 		set_bit(TTM_BO_PRIV_FLAG_MOVING, &bo->priv_flags);
> 
>-		/* ttm_buffer_object_transfer accesses bo->sync_obj */
>-		ret = ttm_buffer_object_transfer(bo, &ghost_obj);
>+		/* take the ref on the sync object before releasing the spinlock */
>+		sync_obj = driver->sync_obj_ref(bo->sync_obj);
> 		spin_unlock(&bdev->fence_lock);
>+
> 		if (tmp_obj)
> 			driver->sync_obj_unref(&tmp_obj);
> 
>+		ret = ttm_buffer_object_transfer(bo, &ghost_obj, sync_obj);
> 		if (ret)
> 			return ret;
> 
>-- 
>1.7.10.4
>

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Attachments on bug 906296: 692871 | 692950