Merge tag 'drm-misc-next-2021-09-16' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

drm-misc-next for $kernel-version:

UAPI Changes:

Cross-subsystem Changes:
  - dma-buf: Avoid a warning with some allocations, Remove
    DMA_FENCE_TRACE macros

Core Changes:
  - bridge: New helper to git rid of panels in drivers
  - fence: Improve dma_fence_add_callback documentation, Improve
    dma_fence_ops->wait documentation
  - ioctl: Unexport drm_ioctl_permit
  - lease: Documentation improvements
  - fourcc: Add new macro to determine the modifier vendor
  - quirks: Add the Steam Deck, Chuwi HiBook, Chuwi Hi10 Pro, Samsung
    Galaxy Book 10.6, KD Kurio Smart C15200 2-in-1, Lenovo Ideapad D330
  - resv: Improve the documentation
  - shmem-helpers: Allocate WC pages on x86, Switch to vmf_insert_pfn
  - sched: Fix for a timer being canceled too soon, Avoid null pointer
    derefence if the fence is null in drm_sched_fence_free, Convert
    drivers to rely on its dependency tracking
  - ttm: Switch to kerneldoc, new helper to clear all DMA mappings, pool
    shrinker optitimization, Remove ttm_tt_destroy_common, Fix for
    unbinding on multiple drivers

Driver Changes:
  - bochs: New PCI IDs
  - msm: Fence ordering impromevemnts
  - stm: Add layer alpha support, zpos
  - v3d: Fix for a Vulkan CTS failure
  - vc4: Conversion to the new bridge helpers
  - vgem: Use shmem helpers
  - virtio: Support mapping exported vram
  - zte: Remove obsolete driver

  - bridge: Probe improvements for it66121, enable DSI EOTP for anx7625,
    errors propagation improvements for anx7625

  - panels: 60fps mode for otm8009a, New driver for Samsung S6D27A1

Signed-off-by: Dave Airlie <airlied@redhat.com>

# gpg: Signature made Thu 16 Sep 2021 17:30:50 AEST
# gpg:                using EDDSA key 5C1337A45ECA9AEB89060E9EE3EF0D6F671851C5
# gpg: Can't check signature: No public key
From: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20210916073132.ptbbmjetm7v3ufq3@gilmour

1 files changed, 15 insertions, 0 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 74296c2d1fed..b1512cefcffa 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -687,6 +687,21 @@ void unregister_shrinker(struct shrinker *shrinker)
 }
 EXPORT_SYMBOL(unregister_shrinker);
 
+/**
+ * synchronize_shrinkers - Wait for all running shrinkers to complete.
+ *
+ * This is equivalent to calling unregister_shrink() and register_shrinker(),
+ * but atomically and with less overhead. This is useful to guarantee that all
+ * shrinker invocations have seen an update, before freeing memory, similar to
+ * rcu.
+ */
+void synchronize_shrinkers(void)
+{
+	down_write(&shrinker_rwsem);
+	up_write(&shrinker_rwsem);
+}
+EXPORT_SYMBOL(synchronize_shrinkers);
+
 #define SHRINK_BATCH 128
 
 static unsigned long do_shrink_slab(struct shrink_control *shrinkctl,