[ 31/48] drm/i915: EBUSY status handling added to i915_gem_fault().

Greg Kroah-Hartman
2013-03-18T21:28:30Z

From: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>

commit e79e0fe380847493266fba557217e2773c61bd1b upstream.

Subsequent threads returning EBUSY from vm_insert_pfn() was not handled
correctly. As a result concurrent access from new threads to
mmapped data caused SIGBUS.

Note that this fixes i-g-t/tests/gem_threaded_tiled_access.

Tested-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Dmitry Rogozhkin <dmitry.v.rogozhkin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/i915/i915_gem.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1186,6 +1186,11 @@ out:
case 0:
case -ERESTARTSYS:
case -EINTR:
+ case -EBUSY:
+ /*
+ * EBUSY is ok: this just means that another thread
+ * already did the job.
+ */
return VM_FAULT_NOPAGE;
case -ENOMEM:
return VM_FAULT_OOM;