drm/i915: EBUSY status handling added to i915_gem_fault().

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>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a230a93935bd16734159de3378888675209483c6..eb339456c1118def643bc923ac8c0f817d5cc999 100644 (file)
--- 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;