[PATCH 4.15 012/146] drm/i915: Clear the in-use marker on execbuf failure

[Greg Kroah-Hartman]

4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>

commit e659d14ed48096f87a678e7ebbdf286a817b4d0e upstream.

If we fail to unbind the vma (due to a signal on an active buffer that
needs to be moved for the next execbuf), then we need to clear the
persistent tracking state we setup for this execbuf.

Fixes: c7c6e46f913b ("drm/i915: Convert execbuf to use struct-of-array packing for critical fields")
Testcase: igt/gem_fenced_exec_thrash/no-spare-fences-busy*
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.14+
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20180219140144.24004-1-chris@xxxxxxxxxxxxxxxxxx
(cherry picked from commit ed2f3532321083cf40e4da4e36234880e0136136)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/i915/i915_gem_execbuffer.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -505,6 +505,8 @@ eb_add_vma(struct i915_execbuffer *eb, u
 		list_add_tail(&vma->exec_link, &eb->unbound);
 		if (drm_mm_node_allocated(&vma->node))
 			err = i915_vma_unbind(vma);
+		if (unlikely(err))
+			vma->exec_flags = NULL;
 	}
 	return err;
 }