Merge remote branch 'keithp/drm-intel-next' of /ssd/git/drm-next into drm-core-next

* 'keithp/drm-intel-next' of /ssd/git/drm-next: (301 commits)
  drm/i915: split PCH clock gating init
  drm/i915: add Ivybridge clock gating init function
  drm/i915: Update the location of the ringbuffers' HWS_PGA registers for IVB.
  drm/i915: Add support for fence registers on Ivybridge.
  drm/i915: Use existing function instead of open-coding fence reg clear.
  drm/i915: split clock gating init into per-chipset functions
  drm/i915: set IBX pch type explicitly
  drm/i915: add Ivy Bridge PCI IDs and driver feature structs
  drm/i915: add PantherPoint PCH ID
  agp/intel: add Ivy Bridge support
  drm/i915: ring support for Ivy Bridge
  drm/i915: page flip support for Ivy Bridge
  drm/i915: interrupt & vblank support for Ivy Bridge
  drm/i915: treat Ivy Bridge watermarks like Sandy Bridge
  drm/i915: manual FDI training for Ivy Bridge
  drm/i915: add swizzle/tiling support for Ivy Bridge
  drm/i915: Ivy Bridge has split display and pipe control
  drm/i915: add IS_IVYBRIDGE macro for checks
  drm/i915: add IS_GEN7 macro to cover Ivy Bridge and later
  drm/i915: split enable/disable vblank code into chipset specific functions
  ...

1 files changed, 7 insertions, 1 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 8859a41806dd..e3378e8d3a5c 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1291,8 +1291,14 @@ __acquires(&gcwq->lock)
                         return true;
                 spin_unlock_irq(&gcwq->lock);
 
-                /* CPU has come up in between, retry migration */
+                /*
+                 * We've raced with CPU hot[un]plug.  Give it a breather
+                 * and retry migration.  cond_resched() is required here;
+                 * otherwise, we might deadlock against cpu_stop trying to
+                 * bring down the CPU on non-preemptive kernel.
+                 */
                 cpu_relax();
+                cond_resched();
         }
 }