drop drm-i915-fix-ref-mutex-deadlock-in-i915_active_wait.patch from 5.4

diff --git a/queue-5.4/drm-i915-fix-ref-mutex-deadlock-in-i915_active_wait.patch b/queue-5.4/drm-i915-fix-ref-mutex-deadlock-in-i915_active_wait.patch
deleted file mode 100644 (file)
index 5d45ae1..0000000
--- a/queue-5.4/drm-i915-fix-ref-mutex-deadlock-in-i915_active_wait.patch
+++ /dev/null
@@ -1,138 +0,0 @@
-From sultan@kerneltoast.com  Fri Apr 10 11:07:34 2020
-From: Sultan Alsawaf <sultan@kerneltoast.com>
-Date: Tue,  7 Apr 2020 00:18:09 -0700
-Subject: drm/i915: Fix ref->mutex deadlock in i915_active_wait()
-To: Greg KH <greg@kroah.com>
-Cc: stable@vger.kernel.org, Jani Nikula <jani.nikula@linux.intel.com>, Joonas Lahtinen <joonas.lahtinen@linux.intel.com>, Rodrigo Vivi <rodrigo.vivi@intel.com>, David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>, Chris Wilson <chris@chris-wilson.co.uk>, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Sultan Alsawaf <sultan@kerneltoast.com>
-Message-ID: <20200407071809.3148-1-sultan@kerneltoast.com>
-
-From: Sultan Alsawaf <sultan@kerneltoast.com>
-
-The following deadlock exists in i915_active_wait() due to a double lock
-on ref->mutex (call chain listed in order from top to bottom):
- i915_active_wait();
- mutex_lock_interruptible(&ref->mutex); <-- ref->mutex first acquired
- i915_active_request_retire();
- node_retire();
- active_retire();
- mutex_lock_nested(&ref->mutex, SINGLE_DEPTH_NESTING); <-- DEADLOCK
-
-Fix the deadlock by skipping the second ref->mutex lock when
-active_retire() is called through i915_active_request_retire().
-
-Note that this bug only affects 5.4 and has since been fixed in 5.5.
-Normally, a backport of the fix from 5.5 would be in order, but the
-patch set that fixes this deadlock involves massive changes that are
-neither feasible nor desirable for backporting [1][2][3]. Therefore,
-this small patch was made to address the deadlock specifically for 5.4.
-
-[1] 274cbf20fd10 ("drm/i915: Push the i915_active.retire into a worker")
-[2] 093b92287363 ("drm/i915: Split i915_active.mutex into an irq-safe spinlock for the rbtree")
-[3] 750bde2fd4ff ("drm/i915: Serialise with remote retirement")
-
-Fixes: 12c255b5dad1 ("drm/i915: Provide an i915_active.acquire callback")
-Cc: <stable@vger.kernel.org> # 5.4.x
-Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
----
- drivers/gpu/drm/i915/i915_active.c |   27 +++++++++++++++++++++++----
- drivers/gpu/drm/i915/i915_active.h |    4 ++--
- 2 files changed, 25 insertions(+), 6 deletions(-)
-
---- a/drivers/gpu/drm/i915/i915_active.c
-+++ b/drivers/gpu/drm/i915/i915_active.c
-@@ -120,13 +120,17 @@ static inline void debug_active_assert(s
- 
- #endif
- 
-+#define I915_ACTIVE_RETIRE_NOLOCK BIT(0)
-+
- static void
- __active_retire(struct i915_active *ref)
- {
-       struct active_node *it, *n;
-       struct rb_root root;
-       bool retire = false;
-+      unsigned long bits;
- 
-+      ref = ptr_unpack_bits(ref, &bits, 2);
-       lockdep_assert_held(&ref->mutex);
- 
-       /* return the unused nodes to our slabcache -- flushing the allocator */
-@@ -138,7 +142,8 @@ __active_retire(struct i915_active *ref)
-               retire = true;
-       }
- 
--      mutex_unlock(&ref->mutex);
-+      if (!(bits & I915_ACTIVE_RETIRE_NOLOCK))
-+              mutex_unlock(&ref->mutex);
-       if (!retire)
-               return;
- 
-@@ -155,13 +160,18 @@ __active_retire(struct i915_active *ref)
- static void
- active_retire(struct i915_active *ref)
- {
-+      struct i915_active *ref_packed = ref;
-+      unsigned long bits;
-+
-+      ref = ptr_unpack_bits(ref, &bits, 2);
-       GEM_BUG_ON(!atomic_read(&ref->count));
-       if (atomic_add_unless(&ref->count, -1, 1))
-               return;
- 
-       /* One active may be flushed from inside the acquire of another */
--      mutex_lock_nested(&ref->mutex, SINGLE_DEPTH_NESTING);
--      __active_retire(ref);
-+      if (!(bits & I915_ACTIVE_RETIRE_NOLOCK))
-+              mutex_lock_nested(&ref->mutex, SINGLE_DEPTH_NESTING);
-+      __active_retire(ref_packed);
- }
- 
- static void
-@@ -170,6 +180,14 @@ node_retire(struct i915_active_request *
-       active_retire(node_from_active(base)->ref);
- }
- 
-+static void
-+node_retire_nolock(struct i915_active_request *base, struct i915_request *rq)
-+{
-+      struct i915_active *ref = node_from_active(base)->ref;
-+
-+      active_retire(ptr_pack_bits(ref, I915_ACTIVE_RETIRE_NOLOCK, 2));
-+}
-+
- static struct i915_active_request *
- active_instance(struct i915_active *ref, struct intel_timeline *tl)
- {
-@@ -421,7 +439,8 @@ int i915_active_wait(struct i915_active
-                       break;
-               }
- 
--              err = i915_active_request_retire(&it->base, BKL(ref));
-+              err = i915_active_request_retire(&it->base, BKL(ref),
-+                                               node_retire_nolock);
-               if (err)
-                       break;
-       }
---- a/drivers/gpu/drm/i915/i915_active.h
-+++ b/drivers/gpu/drm/i915/i915_active.h
-@@ -309,7 +309,7 @@ i915_active_request_isset(const struct i
-  */
- static inline int __must_check
- i915_active_request_retire(struct i915_active_request *active,
--                         struct mutex *mutex)
-+                         struct mutex *mutex, i915_active_retire_fn retire)
- {
-       struct i915_request *request;
-       long ret;
-@@ -327,7 +327,7 @@ i915_active_request_retire(struct i915_a
-       list_del_init(&active->link);
-       RCU_INIT_POINTER(active->request, NULL);
- 
--      active->retire(active, request);
-+      retire(active, request);
- 
-       return 0;
- }

diff --git a/queue-5.4/series b/queue-5.4/series
index e3c66ab9de686641d9501d2e68c0a27f45a5bc2b..8d1a17bd6a542a5b4604fdb5c84dbf16684210fa 100644 (file)
--- a/queue-5.4/series
+++ b/queue-5.4/series
@@ -27,7 +27,6 @@ ib-hfi1-fix-memory-leaks-in-sysfs-registration-and-unregistration.patch
 ib-mlx5-replace-tunnel-mpls-capability-bits-for-tunnel_offloads.patch
 arm-imx-enable-arm_errata_814220-for-i.mx6ul-and-i.mx7d.patch
 arm-imx-only-select-arm_errata_814220-for-armv7-a.patch
-drm-i915-fix-ref-mutex-deadlock-in-i915_active_wait.patch
 ceph-remove-the-extra-slashes-in-the-server-path.patch
 ceph-canonicalize-server-path-in-place.patch
 include-uapi-linux-swab.h-fix-userspace-breakage-use-__bits_per_long-for-swap.patch