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

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>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 76bbb379d389..5fa3419461c5 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1400,6 +1400,11 @@ 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;