From 548e7432dc2da475a18077b612e8d55b8ff51891 Mon Sep 17 00:00:00 2001
From: Christian König <christian.koenig@amd.com>
Date: Fri, 24 Sep 2021 10:55:45 +0200
Subject: dma-buf: add dma_resv_replace_fences v2
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This function allows to replace fences from the shared fence list when
we can gurantee that the operation represented by the original fence has
finished or no accesses to the resources protected by the dma_resv
object any more when the new fence finishes.

Then use this function in the amdkfd code when BOs are unmapped from the
process.

v2: add an example when this is usefull.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220321135856.1331-1-christian.koenig@amd.com
---
 drivers/dma-buf/dma-resv.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

(limited to 'drivers/dma-buf')

diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
index b51416405e86..509060861cf3 100644
--- a/drivers/dma-buf/dma-resv.c
+++ b/drivers/dma-buf/dma-resv.c
@@ -289,6 +289,51 @@ replace:
 }
 EXPORT_SYMBOL(dma_resv_add_shared_fence);
 
+/**
+ * dma_resv_replace_fences - replace fences in the dma_resv obj
+ * @obj: the reservation object
+ * @context: the context of the fences to replace
+ * @replacement: the new fence to use instead
+ *
+ * Replace fences with a specified context with a new fence. Only valid if the
+ * operation represented by the original fence has no longer access to the
+ * resources represented by the dma_resv object when the new fence completes.
+ *
+ * And example for using this is replacing a preemption fence with a page table
+ * update fence which makes the resource inaccessible.
+ */
+void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context,
+			     struct dma_fence *replacement)
+{
+	struct dma_resv_list *list;
+	struct dma_fence *old;
+	unsigned int i;
+
+	dma_resv_assert_held(obj);
+
+	write_seqcount_begin(&obj->seq);
+
+	old = dma_resv_excl_fence(obj);
+	if (old->context == context) {
+		RCU_INIT_POINTER(obj->fence_excl, dma_fence_get(replacement));
+		dma_fence_put(old);
+	}
+
+	list = dma_resv_shared_list(obj);
+	for (i = 0; list && i < list->shared_count; ++i) {
+		old = rcu_dereference_protected(list->shared[i],
+						dma_resv_held(obj));
+		if (old->context != context)
+			continue;
+
+		rcu_assign_pointer(list->shared[i], dma_fence_get(replacement));
+		dma_fence_put(old);
+	}
+
+	write_seqcount_end(&obj->seq);
+}
+EXPORT_SYMBOL(dma_resv_replace_fences);
+
 /**
  * dma_resv_add_excl_fence - Add an exclusive fence.
  * @obj: the reservation object
-- 
cgit v1.2.3


From 8938d48451f5d7cb565dfa68aa0bd0e81985da09 Mon Sep 17 00:00:00 2001
From: Christian König <christian.koenig@amd.com>
Date: Fri, 24 Sep 2021 14:19:22 +0200
Subject: dma-buf: finally make the dma_resv_list private v2
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Drivers should never touch this directly.

v2: drop kerneldoc for now internal handling

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220321135856.1331-2-christian.koenig@amd.com
---
 drivers/dma-buf/dma-resv.c | 11 +++++++++++
 include/linux/dma-resv.h   | 26 +-------------------------
 2 files changed, 12 insertions(+), 25 deletions(-)

(limited to 'drivers/dma-buf')

diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
index 509060861cf3..5001e9b4420a 100644
--- a/drivers/dma-buf/dma-resv.c
+++ b/drivers/dma-buf/dma-resv.c
@@ -56,6 +56,12 @@
 DEFINE_WD_CLASS(reservation_ww_class);
 EXPORT_SYMBOL(reservation_ww_class);
 
+struct dma_resv_list {
+	struct rcu_head rcu;
+	u32 shared_count, shared_max;
+	struct dma_fence __rcu *shared[];
+};
+
 /**
  * dma_resv_list_alloc - allocate fence list
  * @shared_max: number of fences we need space for
@@ -133,6 +139,11 @@ void dma_resv_fini(struct dma_resv *obj)
 }
 EXPORT_SYMBOL(dma_resv_fini);
 
+static inline struct dma_resv_list *dma_resv_shared_list(struct dma_resv *obj)
+{
+	return rcu_dereference_check(obj->fence, dma_resv_held(obj));
+}
+
 /**
  * dma_resv_reserve_shared - Reserve space to add shared fences to
  * a dma_resv.
diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
index 3f53177bdb46..202cc65d0621 100644
--- a/include/linux/dma-resv.h
+++ b/include/linux/dma-resv.h
@@ -47,18 +47,7 @@
 
 extern struct ww_class reservation_ww_class;
 
-/**
- * struct dma_resv_list - a list of shared fences
- * @rcu: for internal use
- * @shared_count: table of shared fences
- * @shared_max: for growing shared fence table
- * @shared: shared fence table
- */
-struct dma_resv_list {
-	struct rcu_head rcu;
-	u32 shared_count, shared_max;
-	struct dma_fence __rcu *shared[];
-};
+struct dma_resv_list;
 
 /**
  * struct dma_resv - a reservation object manages fences for a buffer
@@ -451,19 +440,6 @@ dma_resv_excl_fence(struct dma_resv *obj)
 	return rcu_dereference_check(obj->fence_excl, dma_resv_held(obj));
 }
 
-/**
- * dma_resv_shared_list - get the reservation object's shared fence list
- * @obj: the reservation object
- *
- * Returns the shared fence list. Caller must either hold the objects
- * through dma_resv_lock() or the RCU read side lock through rcu_read_lock(),
- * or one of the variants of each
- */
-static inline struct dma_resv_list *dma_resv_shared_list(struct dma_resv *obj)
-{
-	return rcu_dereference_check(obj->fence, dma_resv_held(obj));
-}
-
 void dma_resv_init(struct dma_resv *obj);
 void dma_resv_fini(struct dma_resv *obj);
 int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences);
-- 
cgit v1.2.3


From 15325e3c1013035c2e3e266ba79a0c3bef905f25 Mon Sep 17 00:00:00 2001
From: Christian König <christian.koenig@amd.com>
Date: Thu, 11 Nov 2021 15:18:34 +0100
Subject: dma-buf: drop the DAG approach for the dma_resv object v3
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

So far we had the approach of using a directed acyclic
graph with the dma_resv obj.

This turned out to have many downsides, especially it means
that every single driver and user of this interface needs
to be aware of this restriction when adding fences. If the
rules for the DAG are not followed then we end up with
potential hard to debug memory corruption, information
leaks or even elephant big security holes because we allow
userspace to access freed up memory.

Since we already took a step back from that by always
looking at all fences we now go a step further and stop
dropping the shared fences when a new exclusive one is
added.

v2: Drop some now superflous documentation
v3: Add some more documentation for the new handling.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220321135856.1331-11-christian.koenig@amd.com
---
 drivers/dma-buf/dma-resv.c | 16 +---------------
 include/linux/dma-buf.h    |  4 +---
 include/linux/dma-resv.h   | 22 +++++-----------------
 3 files changed, 7 insertions(+), 35 deletions(-)

(limited to 'drivers/dma-buf')

diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
index 5001e9b4420a..be65522f0f47 100644
--- a/drivers/dma-buf/dma-resv.c
+++ b/drivers/dma-buf/dma-resv.c
@@ -351,35 +351,21 @@ EXPORT_SYMBOL(dma_resv_replace_fences);
  * @fence: the exclusive fence to add
  *
  * Add a fence to the exclusive slot. @obj must be locked with dma_resv_lock().
- * Note that this function replaces all fences attached to @obj, see also
- * &dma_resv.fence_excl for a discussion of the semantics.
+ * See also &dma_resv.fence_excl for a discussion of the semantics.
  */
 void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence)
 {
 	struct dma_fence *old_fence = dma_resv_excl_fence(obj);
-	struct dma_resv_list *old;
-	u32 i = 0;
 
 	dma_resv_assert_held(obj);
 
-	old = dma_resv_shared_list(obj);
-	if (old)
-		i = old->shared_count;
-
 	dma_fence_get(fence);
 
 	write_seqcount_begin(&obj->seq);
 	/* write_seqcount_begin provides the necessary memory barrier */
 	RCU_INIT_POINTER(obj->fence_excl, fence);
-	if (old)
-		old->shared_count = 0;
 	write_seqcount_end(&obj->seq);
 
-	/* inplace update, no shared fences */
-	while (i--)
-		dma_fence_put(rcu_dereference_protected(old->shared[i],
-						dma_resv_held(obj)));
-
 	dma_fence_put(old_fence);
 }
 EXPORT_SYMBOL(dma_resv_add_excl_fence);
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 7ab50076e7a6..85ab5554425e 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -424,9 +424,7 @@ struct dma_buf {
 	 * IMPORTANT:
 	 *
 	 * All drivers must obey the struct dma_resv rules, specifically the
-	 * rules for updating fences, see &dma_resv.fence_excl and
-	 * &dma_resv.fence. If these dependency rules are broken access tracking
-	 * can be lost resulting in use after free issues.
+	 * rules for updating and obeying fences.
 	 */
 	struct dma_resv *resv;
 
diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
index 202cc65d0621..dccaf7b1663e 100644
--- a/include/linux/dma-resv.h
+++ b/include/linux/dma-resv.h
@@ -93,23 +93,11 @@ struct dma_resv {
 	 *
 	 * The exclusive fence, if there is one currently.
 	 *
-	 * There are two ways to update this fence:
-	 *
-	 * - First by calling dma_resv_add_excl_fence(), which replaces all
-	 *   fences attached to the reservation object. To guarantee that no
-	 *   fences are lost, this new fence must signal only after all previous
-	 *   fences, both shared and exclusive, have signalled. In some cases it
-	 *   is convenient to achieve that by attaching a struct dma_fence_array
-	 *   with all the new and old fences.
-	 *
-	 * - Alternatively the fence can be set directly, which leaves the
-	 *   shared fences unchanged. To guarantee that no fences are lost, this
-	 *   new fence must signal only after the previous exclusive fence has
-	 *   signalled. Since the shared fences are staying intact, it is not
-	 *   necessary to maintain any ordering against those. If semantically
-	 *   only a new access is added without actually treating the previous
-	 *   one as a dependency the exclusive fences can be strung together
-	 *   using struct dma_fence_chain.
+	 * To guarantee that no fences are lost, this new fence must signal
+	 * only after the previous exclusive fence has signalled. If
+	 * semantically only a new access is added without actually treating the
+	 * previous one as a dependency the exclusive fences can be strung
+	 * together using struct dma_fence_chain.
 	 *
 	 * Note that actual semantics of what an exclusive or shared fence mean
 	 * is defined by the user, for reservation objects shared across drivers
-- 
cgit v1.2.3


From d791aec9ff43df4ea0a6690eabd6c395e982ef6f Mon Sep 17 00:00:00 2001
From: Sui Jingfeng <15330273260@189.cn>
Date: Sat, 2 Apr 2022 21:44:13 +0800
Subject: drivers/dma-buf: dma-buf.c: fix a typo
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Sui Jingfeng <15330273260@189.cn>
Link: https://patchwork.freedesktop.org/patch/msgid/20220402134413.1705246-1-15330273260@189.cn
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
---
 drivers/dma-buf/dma-buf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'drivers/dma-buf')

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 602b12d7470d..33995ec3218a 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -443,7 +443,7 @@ err_alloc_file:
  *    as a file descriptor by calling dma_buf_fd().
  *
  * 2. Userspace passes this file-descriptors to all drivers it wants this buffer
- *    to share with: First the filedescriptor is converted to a &dma_buf using
+ *    to share with: First the file descriptor is converted to a &dma_buf using
  *    dma_buf_get(). Then the buffer is attached to the device using
  *    dma_buf_attach().
  *
-- 
cgit v1.2.3


From 92cedee6a6a3e6fcc3ffc0e3866baae5f6f76ac1 Mon Sep 17 00:00:00 2001
From: Christian König <christian.koenig@amd.com>
Date: Wed, 3 Nov 2021 10:02:08 +0100
Subject: dma-buf: add dma_resv_get_singleton v2
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Add a function to simplify getting a single fence for all the fences in
the dma_resv object.

v2: fix ref leak in error handling

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220321135856.1331-3-christian.koenig@amd.com
---
 drivers/dma-buf/dma-resv.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/dma-resv.h   |  2 ++
 2 files changed, 56 insertions(+)

(limited to 'drivers/dma-buf')

diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
index be65522f0f47..ff16da0a54ec 100644
--- a/drivers/dma-buf/dma-resv.c
+++ b/drivers/dma-buf/dma-resv.c
@@ -34,6 +34,7 @@
  */
 
 #include <linux/dma-resv.h>
+#include <linux/dma-fence-array.h>
 #include <linux/export.h>
 #include <linux/mm.h>
 #include <linux/sched/mm.h>
@@ -636,6 +637,59 @@ int dma_resv_get_fences(struct dma_resv *obj, bool write,
 }
 EXPORT_SYMBOL_GPL(dma_resv_get_fences);
 
+/**
+ * dma_resv_get_singleton - Get a single fence for all the fences
+ * @obj: the reservation object
+ * @write: true if we should return all fences
+ * @fence: the resulting fence
+ *
+ * Get a single fence representing all the fences inside the resv object.
+ * Returns either 0 for success or -ENOMEM.
+ *
+ * Warning: This can't be used like this when adding the fence back to the resv
+ * object since that can lead to stack corruption when finalizing the
+ * dma_fence_array.
+ *
+ * Returns 0 on success and negative error values on failure.
+ */
+int dma_resv_get_singleton(struct dma_resv *obj, bool write,
+			   struct dma_fence **fence)
+{
+	struct dma_fence_array *array;
+	struct dma_fence **fences;
+	unsigned count;
+	int r;
+
+	r = dma_resv_get_fences(obj, write, &count, &fences);
+        if (r)
+		return r;
+
+	if (count == 0) {
+		*fence = NULL;
+		return 0;
+	}
+
+	if (count == 1) {
+		*fence = fences[0];
+		kfree(fences);
+		return 0;
+	}
+
+	array = dma_fence_array_create(count, fences,
+				       dma_fence_context_alloc(1),
+				       1, false);
+	if (!array) {
+		while (count--)
+			dma_fence_put(fences[count]);
+		kfree(fences);
+		return -ENOMEM;
+	}
+
+	*fence = &array->base;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dma_resv_get_singleton);
+
 /**
  * dma_resv_wait_timeout - Wait on reservation's objects
  * shared and/or exclusive fences.
diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
index dccaf7b1663e..233ed4f14d9e 100644
--- a/include/linux/dma-resv.h
+++ b/include/linux/dma-resv.h
@@ -437,6 +437,8 @@ void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context,
 void dma_resv_add_excl_fence(struct dma_resv *obj, struct dma_fence *fence);
 int dma_resv_get_fences(struct dma_resv *obj, bool write,
 			unsigned int *num_fences, struct dma_fence ***fences);
+int dma_resv_get_singleton(struct dma_resv *obj, bool write,
+			   struct dma_fence **fence);
 int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src);
 long dma_resv_wait_timeout(struct dma_resv *obj, bool wait_all, bool intr,
 			   unsigned long timeout);
-- 
cgit v1.2.3


From 71d637823cac7748079a912e0373476c7cf6f985 Mon Sep 17 00:00:00 2001
From: Christian König <christian.koenig@amd.com>
Date: Wed, 3 Nov 2021 13:35:14 +0100
Subject: dma-buf: finally make dma_resv_excl_fence private v2
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Drivers should never touch this directly.

v2: fix rebase clash

Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220321135856.1331-10-christian.koenig@amd.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/dma-buf/dma-resv.c |  6 ++++++
 include/linux/dma-resv.h   | 17 -----------------
 2 files changed, 6 insertions(+), 17 deletions(-)

(limited to 'drivers/dma-buf')

diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
index ff16da0a54ec..15ffac35439d 100644
--- a/drivers/dma-buf/dma-resv.c
+++ b/drivers/dma-buf/dma-resv.c
@@ -140,6 +140,12 @@ void dma_resv_fini(struct dma_resv *obj)
 }
 EXPORT_SYMBOL(dma_resv_fini);
 
+static inline struct dma_fence *
+dma_resv_excl_fence(struct dma_resv *obj)
+{
+       return rcu_dereference_check(obj->fence_excl, dma_resv_held(obj));
+}
+
 static inline struct dma_resv_list *dma_resv_shared_list(struct dma_resv *obj)
 {
 	return rcu_dereference_check(obj->fence, dma_resv_held(obj));
diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
index 233ed4f14d9e..ecb697d4d861 100644
--- a/include/linux/dma-resv.h
+++ b/include/linux/dma-resv.h
@@ -411,23 +411,6 @@ static inline void dma_resv_unlock(struct dma_resv *obj)
 	ww_mutex_unlock(&obj->lock);
 }
 
-/**
- * dma_resv_excl_fence - return the object's exclusive fence
- * @obj: the reservation object
- *
- * Returns the exclusive fence (if any). Caller must either hold the objects
- * through dma_resv_lock() or the RCU read side lock through rcu_read_lock(),
- * or one of the variants of each
- *
- * RETURNS
- * The exclusive fence or NULL
- */
-static inline struct dma_fence *
-dma_resv_excl_fence(struct dma_resv *obj)
-{
-	return rcu_dereference_check(obj->fence_excl, dma_resv_held(obj));
-}
-
 void dma_resv_init(struct dma_resv *obj);
 void dma_resv_fini(struct dma_resv *obj);
 int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences);
-- 
cgit v1.2.3


From c8d4c18bfbc4ab467188dbe45cc8155759f49d9e Mon Sep 17 00:00:00 2001
From: Christian König <christian.koenig@amd.com>
Date: Tue, 16 Nov 2021 15:20:45 +0100
Subject: dma-buf/drivers: make reserving a shared slot mandatory v4
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Audit all the users of dma_resv_add_excl_fence() and make sure they
reserve a shared slot also when only trying to add an exclusive fence.

This is the next step towards handling the exclusive fence like a
shared one.

v2: fix missed case in amdgpu
v3: and two more radeon, rename function
v4: add one more case to TTM, fix i915 after rebase

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220406075132.3263-2-christian.koenig@amd.com
---
 drivers/dma-buf/dma-resv.c                         | 10 ++--
 drivers/dma-buf/st-dma-resv.c                      | 64 ++++++++++------------
 drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c   |  4 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_object.c         |  8 +++
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c             |  4 +-
 drivers/gpu/drm/amd/amdkfd/kfd_svm.c               |  2 +-
 drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c       |  8 +--
 drivers/gpu/drm/i915/gem/i915_gem_clflush.c        |  3 +-
 drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c     | 10 ++--
 drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c       |  6 +-
 .../gpu/drm/i915/gem/selftests/i915_gem_migrate.c  |  5 +-
 drivers/gpu/drm/i915/i915_vma.c                    | 10 +++-
 .../gpu/drm/i915/selftests/intel_memory_region.c   |  7 +++
 drivers/gpu/drm/lima/lima_gem.c                    | 10 ++--
 drivers/gpu/drm/msm/msm_gem_submit.c               | 18 +++---
 drivers/gpu/drm/nouveau/nouveau_fence.c            |  8 +--
 drivers/gpu/drm/panfrost/panfrost_job.c            |  4 ++
 drivers/gpu/drm/qxl/qxl_release.c                  |  2 +-
 drivers/gpu/drm/radeon/radeon_cs.c                 |  4 ++
 drivers/gpu/drm/radeon/radeon_object.c             |  8 +++
 drivers/gpu/drm/radeon/radeon_vm.c                 |  2 +-
 drivers/gpu/drm/ttm/ttm_bo.c                       |  8 ++-
 drivers/gpu/drm/ttm/ttm_bo_util.c                  | 12 +++-
 drivers/gpu/drm/ttm/ttm_execbuf_util.c             | 15 +++--
 drivers/gpu/drm/v3d/v3d_gem.c                      | 15 +++--
 drivers/gpu/drm/vc4/vc4_gem.c                      |  2 +-
 drivers/gpu/drm/vgem/vgem_fence.c                  | 12 ++--
 drivers/gpu/drm/virtio/virtgpu_gem.c               |  9 +++
 drivers/gpu/drm/vmwgfx/vmwgfx_bo.c                 | 16 ++++--
 include/linux/dma-resv.h                           |  4 +-
 30 files changed, 176 insertions(+), 114 deletions(-)

(limited to 'drivers/dma-buf')

diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
index 15ffac35439d..8c650b96357a 100644
--- a/drivers/dma-buf/dma-resv.c
+++ b/drivers/dma-buf/dma-resv.c
@@ -152,7 +152,7 @@ static inline struct dma_resv_list *dma_resv_shared_list(struct dma_resv *obj)
 }
 
 /**
- * dma_resv_reserve_shared - Reserve space to add shared fences to
+ * dma_resv_reserve_fences - Reserve space to add shared fences to
  * a dma_resv.
  * @obj: reservation object
  * @num_fences: number of fences we want to add
@@ -167,7 +167,7 @@ static inline struct dma_resv_list *dma_resv_shared_list(struct dma_resv *obj)
  * RETURNS
  * Zero for success, or -errno
  */
-int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences)
+int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences)
 {
 	struct dma_resv_list *old, *new;
 	unsigned int i, j, k, max;
@@ -230,7 +230,7 @@ int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences)
 
 	return 0;
 }
-EXPORT_SYMBOL(dma_resv_reserve_shared);
+EXPORT_SYMBOL(dma_resv_reserve_fences);
 
 #ifdef CONFIG_DEBUG_MUTEXES
 /**
@@ -238,7 +238,7 @@ EXPORT_SYMBOL(dma_resv_reserve_shared);
  * @obj: the dma_resv object to reset
  *
  * Reset the number of pre-reserved shared slots to test that drivers do
- * correct slot allocation using dma_resv_reserve_shared(). See also
+ * correct slot allocation using dma_resv_reserve_fences(). See also
  * &dma_resv_list.shared_max.
  */
 void dma_resv_reset_shared_max(struct dma_resv *obj)
@@ -260,7 +260,7 @@ EXPORT_SYMBOL(dma_resv_reset_shared_max);
  * @fence: the shared fence to add
  *
  * Add a fence to a shared slot, @obj must be locked with dma_resv_lock(), and
- * dma_resv_reserve_shared() has been called.
+ * dma_resv_reserve_fences() has been called.
  *
  * See also &dma_resv.fence for a discussion of the semantics.
  */
diff --git a/drivers/dma-buf/st-dma-resv.c b/drivers/dma-buf/st-dma-resv.c
index cbe999c6e7a6..d2e61f6ae989 100644
--- a/drivers/dma-buf/st-dma-resv.c
+++ b/drivers/dma-buf/st-dma-resv.c
@@ -75,17 +75,16 @@ static int test_signaling(void *arg, bool shared)
 		goto err_free;
 	}
 
-	if (shared) {
-		r = dma_resv_reserve_shared(&resv, 1);
-		if (r) {
-			pr_err("Resv shared slot allocation failed\n");
-			goto err_unlock;
-		}
+	r = dma_resv_reserve_fences(&resv, 1);
+	if (r) {
+		pr_err("Resv shared slot allocation failed\n");
+		goto err_unlock;
+	}
 
+	if (shared)
 		dma_resv_add_shared_fence(&resv, f);
-	} else {
+	else
 		dma_resv_add_excl_fence(&resv, f);
-	}
 
 	if (dma_resv_test_signaled(&resv, shared)) {
 		pr_err("Resv unexpectedly signaled\n");
@@ -134,17 +133,16 @@ static int test_for_each(void *arg, bool shared)
 		goto err_free;
 	}
 
-	if (shared) {
-		r = dma_resv_reserve_shared(&resv, 1);
-		if (r) {
-			pr_err("Resv shared slot allocation failed\n");
-			goto err_unlock;
-		}
+	r = dma_resv_reserve_fences(&resv, 1);
+	if (r) {
+		pr_err("Resv shared slot allocation failed\n");
+		goto err_unlock;
+	}
 
+	if (shared)
 		dma_resv_add_shared_fence(&resv, f);
-	} else {
+	else
 		dma_resv_add_excl_fence(&resv, f);
-	}
 
 	r = -ENOENT;
 	dma_resv_for_each_fence(&cursor, &resv, shared, fence) {
@@ -206,18 +204,17 @@ static int test_for_each_unlocked(void *arg, bool shared)
 		goto err_free;
 	}
 
-	if (shared) {
-		r = dma_resv_reserve_shared(&resv, 1);
-		if (r) {
-			pr_err("Resv shared slot allocation failed\n");
-			dma_resv_unlock(&resv);
-			goto err_free;
-		}
+	r = dma_resv_reserve_fences(&resv, 1);
+	if (r) {
+		pr_err("Resv shared slot allocation failed\n");
+		dma_resv_unlock(&resv);
+		goto err_free;
+	}
 
+	if (shared)
 		dma_resv_add_shared_fence(&resv, f);
-	} else {
+	else
 		dma_resv_add_excl_fence(&resv, f);
-	}
 	dma_resv_unlock(&resv);
 
 	r = -ENOENT;
@@ -290,18 +287,17 @@ static int test_get_fences(void *arg, bool shared)
 		goto err_resv;
 	}
 
-	if (shared) {
-		r = dma_resv_reserve_shared(&resv, 1);
-		if (r) {
-			pr_err("Resv shared slot allocation failed\n");
-			dma_resv_unlock(&resv);
-			goto err_resv;
-		}
+	r = dma_resv_reserve_fences(&resv, 1);
+	if (r) {
+		pr_err("Resv shared slot allocation failed\n");
+		dma_resv_unlock(&resv);
+		goto err_resv;
+	}
 
+	if (shared)
 		dma_resv_add_shared_fence(&resv, f);
-	} else {
+	else
 		dma_resv_add_excl_fence(&resv, f);
-	}
 	dma_resv_unlock(&resv);
 
 	r = dma_resv_get_fences(&resv, shared, &i, &fences);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index 900ed2a7483b..98b1736bb221 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1233,7 +1233,7 @@ static int init_kfd_vm(struct amdgpu_vm *vm, void **process_info,
 				  AMDGPU_FENCE_OWNER_KFD, false);
 	if (ret)
 		goto wait_pd_fail;
-	ret = dma_resv_reserve_shared(vm->root.bo->tbo.base.resv, 1);
+	ret = dma_resv_reserve_fences(vm->root.bo->tbo.base.resv, 1);
 	if (ret)
 		goto reserve_shared_fail;
 	amdgpu_bo_fence(vm->root.bo,
@@ -2571,7 +2571,7 @@ int amdgpu_amdkfd_add_gws_to_process(void *info, void *gws, struct kgd_mem **mem
 	 * Add process eviction fence to bo so they can
 	 * evict each other.
 	 */
-	ret = dma_resv_reserve_shared(gws_bo->tbo.base.resv, 1);
+	ret = dma_resv_reserve_fences(gws_bo->tbo.base.resv, 1);
 	if (ret)
 		goto reserve_shared_fail;
 	amdgpu_bo_fence(gws_bo, &process_info->eviction_fence->base, true);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
index 25731719c627..6f57a2fd5fe3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
@@ -1388,6 +1388,14 @@ void amdgpu_bo_fence(struct amdgpu_bo *bo, struct dma_fence *fence,
 		     bool shared)
 {
 	struct dma_resv *resv = bo->tbo.base.resv;
+	int r;
+
+	r = dma_resv_reserve_fences(resv, 1);
+	if (r) {
+		/* As last resort on OOM we block for the fence */
+		dma_fence_wait(fence, false);
+		return;
+	}
 
 	if (shared)
 		dma_resv_add_shared_fence(resv, fence);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 5d11978c162e..b13451255e8b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -2926,7 +2926,7 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm)
 	if (r)
 		goto error_free_root;
 
-	r = dma_resv_reserve_shared(root_bo->tbo.base.resv, 1);
+	r = dma_resv_reserve_fences(root_bo->tbo.base.resv, 1);
 	if (r)
 		goto error_unreserve;
 
@@ -3369,7 +3369,7 @@ bool amdgpu_vm_handle_fault(struct amdgpu_device *adev, u32 pasid,
 		value = 0;
 	}
 
-	r = dma_resv_reserve_shared(root->tbo.base.resv, 1);
+	r = dma_resv_reserve_fences(root->tbo.base.resv, 1);
 	if (r) {
 		pr_debug("failed %d to reserve fence slot\n", r);
 		goto error_unlock;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 3b8856b4cece..b3fc3e958227 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -548,7 +548,7 @@ svm_range_vram_node_new(struct amdgpu_device *adev, struct svm_range *prange,
 		goto reserve_bo_failed;
 	}
 
-	r = dma_resv_reserve_shared(bo->tbo.base.resv, 1);
+	r = dma_resv_reserve_fences(bo->tbo.base.resv, 1);
 	if (r) {
 		pr_debug("failed %d to reserve bo\n", r);
 		amdgpu_bo_unreserve(bo);
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c b/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c
index 5f502c49aec2..53f7c78628a4 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c
@@ -179,11 +179,9 @@ static int submit_fence_sync(struct etnaviv_gem_submit *submit)
 		struct etnaviv_gem_submit_bo *bo = &submit->bos[i];
 		struct dma_resv *robj = bo->obj->base.resv;
 
-		if (!(bo->flags & ETNA_SUBMIT_BO_WRITE)) {
-			ret = dma_resv_reserve_shared(robj, 1);
-			if (ret)
-				return ret;
-		}
+		ret = dma_resv_reserve_fences(robj, 1);
+		if (ret)
+			return ret;
 
 		if (submit->flags & ETNA_SUBMIT_NO_IMPLICIT)
 			continue;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_clflush.c b/drivers/gpu/drm/i915/gem/i915_gem_clflush.c
index ce91b23385cf..1fd0cc9ca213 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_clflush.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_clflush.c
@@ -108,7 +108,8 @@ bool i915_gem_clflush_object(struct drm_i915_gem_object *obj,
 	trace_i915_gem_object_clflush(obj);
 
 	clflush = NULL;
-	if (!(flags & I915_CLFLUSH_SYNC))
+	if (!(flags & I915_CLFLUSH_SYNC) &&
+	    dma_resv_reserve_fences(obj->base.resv, 1) == 0)
 		clflush = clflush_work_create(obj);
 	if (clflush) {
 		i915_sw_fence_await_reservation(&clflush->base.chain,
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index d42f437149c9..78f8797853ce 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -998,11 +998,9 @@ static int eb_validate_vmas(struct i915_execbuffer *eb)
 			}
 		}
 
-		if (!(ev->flags & EXEC_OBJECT_WRITE)) {
-			err = dma_resv_reserve_shared(vma->obj->base.resv, 1);
-			if (err)
-				return err;
-		}
+		err = dma_resv_reserve_fences(vma->obj->base.resv, 1);
+		if (err)
+			return err;
 
 		GEM_BUG_ON(drm_mm_node_allocated(&vma->node) &&
 			   eb_vma_misplaced(&eb->exec[i], vma, ev->flags));
@@ -2303,7 +2301,7 @@ static int eb_parse(struct i915_execbuffer *eb)
 	if (IS_ERR(batch))
 		return PTR_ERR(batch);
 
-	err = dma_resv_reserve_shared(shadow->obj->base.resv, 1);
+	err = dma_resv_reserve_fences(shadow->obj->base.resv, 1);
 	if (err)
 		return err;
 
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
index 1ebe6e4086a1..432ac74ff225 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm_move.c
@@ -611,7 +611,11 @@ int i915_gem_obj_copy_ttm(struct drm_i915_gem_object *dst,
 	assert_object_held(src);
 	i915_deps_init(&deps, GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN);
 
-	ret = dma_resv_reserve_shared(src_bo->base.resv, 1);
+	ret = dma_resv_reserve_fences(src_bo->base.resv, 1);
+	if (ret)
+		return ret;
+
+	ret = dma_resv_reserve_fences(dst_bo->base.resv, 1);
 	if (ret)
 		return ret;
 
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_migrate.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_migrate.c
index d534141b2cf7..0e52eb87cd55 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_migrate.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_migrate.c
@@ -216,7 +216,10 @@ static int __igt_lmem_pages_migrate(struct intel_gt *gt,
 					  i915_gem_object_is_lmem(obj),
 					  0xdeadbeaf, &rq);
 		if (rq) {
-			dma_resv_add_excl_fence(obj->base.resv, &rq->fence);
+			err = dma_resv_reserve_fences(obj->base.resv, 1);
+			if (!err)
+				dma_resv_add_excl_fence(obj->base.resv,
+							&rq->fence);
 			i915_gem_object_set_moving_fence(obj, &rq->fence);
 			i915_request_put(rq);
 		}
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 94fcdb7bd21d..bae3423f58e8 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -1819,6 +1819,12 @@ int _i915_vma_move_to_active(struct i915_vma *vma,
 			intel_frontbuffer_put(front);
 		}
 
+		if (!(flags & __EXEC_OBJECT_NO_RESERVE)) {
+			err = dma_resv_reserve_fences(vma->obj->base.resv, 1);
+			if (unlikely(err))
+				return err;
+		}
+
 		if (fence) {
 			dma_resv_add_excl_fence(vma->obj->base.resv, fence);
 			obj->write_domain = I915_GEM_DOMAIN_RENDER;
@@ -1826,7 +1832,7 @@ int _i915_vma_move_to_active(struct i915_vma *vma,
 		}
 	} else {
 		if (!(flags & __EXEC_OBJECT_NO_RESERVE)) {
-			err = dma_resv_reserve_shared(vma->obj->base.resv, 1);
+			err = dma_resv_reserve_fences(vma->obj->base.resv, 1);
 			if (unlikely(err))
 				return err;
 		}
@@ -2044,7 +2050,7 @@ int i915_vma_unbind_async(struct i915_vma *vma, bool trylock_vm)
 	if (!obj->mm.rsgt)
 		return -EBUSY;
 
-	err = dma_resv_reserve_shared(obj->base.resv, 1);
+	err = dma_resv_reserve_fences(obj->base.resv, 1);
 	if (err)
 		return -EBUSY;
 
diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
index ba32893e0873..6114e013092b 100644
--- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
@@ -1043,6 +1043,13 @@ static int igt_lmem_write_cpu(void *arg)
 	}
 
 	i915_gem_object_lock(obj, NULL);
+
+	err = dma_resv_reserve_fences(obj->base.resv, 1);
+	if (err) {
+		i915_gem_object_unlock(obj);
+		goto out_put;
+	}
+
 	/* Put the pages into a known state -- from the gpu for added fun */
 	intel_engine_pm_get(engine);
 	err = intel_context_migrate_clear(engine->gt->migrate.context, NULL,
diff --git a/drivers/gpu/drm/lima/lima_gem.c b/drivers/gpu/drm/lima/lima_gem.c
index 55bb1ec3c4f7..e0a11ee0e86d 100644
--- a/drivers/gpu/drm/lima/lima_gem.c
+++ b/drivers/gpu/drm/lima/lima_gem.c
@@ -257,13 +257,11 @@ int lima_gem_get_info(struct drm_file *file, u32 handle, u32 *va, u64 *offset)
 static int lima_gem_sync_bo(struct lima_sched_task *task, struct lima_bo *bo,
 			    bool write, bool explicit)
 {
-	int err = 0;
+	int err;
 
-	if (!write) {
-		err = dma_resv_reserve_shared(lima_bo_resv(bo), 1);
-		if (err)
-			return err;
-	}
+	err = dma_resv_reserve_fences(lima_bo_resv(bo), 1);
+	if (err)
+		return err;
 
 	/* explicit sync use user passed dep fence */
 	if (explicit)
diff --git a/drivers/gpu/drm/msm/msm_gem_submit.c b/drivers/gpu/drm/msm/msm_gem_submit.c
index c6d60c8d286d..3164db8be893 100644
--- a/drivers/gpu/drm/msm/msm_gem_submit.c
+++ b/drivers/gpu/drm/msm/msm_gem_submit.c
@@ -320,16 +320,14 @@ static int submit_fence_sync(struct msm_gem_submit *submit, bool no_implicit)
 		struct drm_gem_object *obj = &submit->bos[i].obj->base;
 		bool write = submit->bos[i].flags & MSM_SUBMIT_BO_WRITE;
 
-		if (!write) {
-			/* NOTE: _reserve_shared() must happen before
-			 * _add_shared_fence(), which makes this a slightly
-			 * strange place to call it.  OTOH this is a
-			 * convenient can-fail point to hook it in.
-			 */
-			ret = dma_resv_reserve_shared(obj->resv, 1);
-			if (ret)
-				return ret;
-		}
+		/* NOTE: _reserve_shared() must happen before
+		 * _add_shared_fence(), which makes this a slightly
+		 * strange place to call it.  OTOH this is a
+		 * convenient can-fail point to hook it in.
+		 */
+		ret = dma_resv_reserve_fences(obj->resv, 1);
+		if (ret)
+			return ret;
 
 		/* exclusive fences must be ordered */
 		if (no_implicit && !write)
diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c b/drivers/gpu/drm/nouveau/nouveau_fence.c
index a3a04e0d76ec..0268259e97eb 100644
--- a/drivers/gpu/drm/nouveau/nouveau_fence.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fence.c
@@ -346,11 +346,9 @@ nouveau_fence_sync(struct nouveau_bo *nvbo, struct nouveau_channel *chan,
 	struct dma_resv *resv = nvbo->bo.base.resv;
 	int i, ret;
 
-	if (!exclusive) {
-		ret = dma_resv_reserve_shared(resv, 1);
-		if (ret)
-			return ret;
-	}
+	ret = dma_resv_reserve_fences(resv, 1);
+	if (ret)
+		return ret;
 
 	/* Waiting for the exclusive fence first causes performance regressions
 	 * under some circumstances. So manually wait for the shared ones first.
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index a6925dbb6224..c34114560e49 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -247,6 +247,10 @@ static int panfrost_acquire_object_fences(struct drm_gem_object **bos,
 	int i, ret;
 
 	for (i = 0; i < bo_count; i++) {
+		ret = dma_resv_reserve_fences(bos[i]->resv, 1);
+		if (ret)
+			return ret;
+
 		/* panfrost always uses write mode in its current uapi */
 		ret = drm_sched_job_add_implicit_dependencies(job, bos[i],
 							      true);
diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index 469979cd0341..cde1e8ddaeaa 100644
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -200,7 +200,7 @@ static int qxl_release_validate_bo(struct qxl_bo *bo)
 			return ret;
 	}
 
-	ret = dma_resv_reserve_shared(bo->tbo.base.resv, 1);
+	ret = dma_resv_reserve_fences(bo->tbo.base.resv, 1);
 	if (ret)
 		return ret;
 
diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeon/radeon_cs.c
index 9ed2b2700e0a..446f7bae54c4 100644
--- a/drivers/gpu/drm/radeon/radeon_cs.c
+++ b/drivers/gpu/drm/radeon/radeon_cs.c
@@ -535,6 +535,10 @@ static int radeon_bo_vm_update_pte(struct radeon_cs_parser *p,
 			return r;
 
 		radeon_sync_fence(&p->ib.sync, bo_va->last_pt_update);
+
+		r = dma_resv_reserve_fences(bo->tbo.base.resv, 1);
+		if (r)
+			return r;
 	}
 
 	return radeon_vm_clear_invalids(rdev, vm);
diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index 91a72cd14304..7ffd2e90f325 100644
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -782,6 +782,14 @@ void radeon_bo_fence(struct radeon_bo *bo, struct radeon_fence *fence,
 		     bool shared)
 {
 	struct dma_resv *resv = bo->tbo.base.resv;
+	int r;
+
+	r = dma_resv_reserve_fences(resv, 1);
+	if (r) {
+		/* As last resort on OOM we block for the fence */
+		dma_fence_wait(&fence->base, false);
+		return;
+	}
 
 	if (shared)
 		dma_resv_add_shared_fence(resv, &fence->base);
diff --git a/drivers/gpu/drm/radeon/radeon_vm.c b/drivers/gpu/drm/radeon/radeon_vm.c
index bb53016f3138..987cabbf1318 100644
--- a/drivers/gpu/drm/radeon/radeon_vm.c
+++ b/drivers/gpu/drm/radeon/radeon_vm.c
@@ -831,7 +831,7 @@ static int radeon_vm_update_ptes(struct radeon_device *rdev,
 		int r;
 
 		radeon_sync_resv(rdev, &ib->sync, pt->tbo.base.resv, true);
-		r = dma_resv_reserve_shared(pt->tbo.base.resv, 1);
+		r = dma_resv_reserve_fences(pt->tbo.base.resv, 1);
 		if (r)
 			return r;
 
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index e5fd0f2c0299..c49996cf25d0 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -151,6 +151,10 @@ static int ttm_bo_handle_move_mem(struct ttm_buffer_object *bo,
 		}
 	}
 
+	ret = dma_resv_reserve_fences(bo->base.resv, 1);
+	if (ret)
+		goto out_err;
+
 	ret = bdev->funcs->move(bo, evict, ctx, mem, hop);
 	if (ret) {
 		if (ret == -EMULTIHOP)
@@ -735,7 +739,7 @@ static int ttm_bo_add_move_fence(struct ttm_buffer_object *bo,
 
 	dma_resv_add_shared_fence(bo->base.resv, fence);
 
-	ret = dma_resv_reserve_shared(bo->base.resv, 1);
+	ret = dma_resv_reserve_fences(bo->base.resv, 1);
 	if (unlikely(ret)) {
 		dma_fence_put(fence);
 		return ret;
@@ -794,7 +798,7 @@ int ttm_bo_mem_space(struct ttm_buffer_object *bo,
 	bool type_found = false;
 	int i, ret;
 
-	ret = dma_resv_reserve_shared(bo->base.resv, 1);
+	ret = dma_resv_reserve_fences(bo->base.resv, 1);
 	if (unlikely(ret))
 		return ret;
 
diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index 219dd81bbeab..1b96b91bf81b 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -221,9 +221,6 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
 
 	fbo->base = *bo;
 
-	ttm_bo_get(bo);
-	fbo->bo = bo;
-
 	/**
 	 * Fix up members that we shouldn't copy directly:
 	 * TODO: Explicit member copy would probably be better here.
@@ -250,6 +247,15 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
 	ret = dma_resv_trylock(&fbo->base.base._resv);
 	WARN_ON(!ret);
 
+	ret = dma_resv_reserve_fences(&fbo->base.base._resv, 1);
+	if (ret) {
+		kfree(fbo);
+		return ret;
+	}
+
+	ttm_bo_get(bo);
+	fbo->bo = bo;
+
 	ttm_bo_move_to_lru_tail_unlocked(&fbo->base);
 
 	*new_obj = &fbo->base;
diff --git a/drivers/gpu/drm/ttm/ttm_execbuf_util.c b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
index 071c48d672c6..789c645f004e 100644
--- a/drivers/gpu/drm/ttm/ttm_execbuf_util.c
+++ b/drivers/gpu/drm/ttm/ttm_execbuf_util.c
@@ -90,6 +90,7 @@ int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
 
 	list_for_each_entry(entry, list, head) {
 		struct ttm_buffer_object *bo = entry->bo;
+		unsigned int num_fences;
 
 		ret = ttm_bo_reserve(bo, intr, (ticket == NULL), ticket);
 		if (ret == -EALREADY && dups) {
@@ -100,12 +101,10 @@ int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
 			continue;
 		}
 
+		num_fences = min(entry->num_shared, 1u);
 		if (!ret) {
-			if (!entry->num_shared)
-				continue;
-
-			ret = dma_resv_reserve_shared(bo->base.resv,
-								entry->num_shared);
+			ret = dma_resv_reserve_fences(bo->base.resv,
+						      num_fences);
 			if (!ret)
 				continue;
 		}
@@ -120,9 +119,9 @@ int ttm_eu_reserve_buffers(struct ww_acquire_ctx *ticket,
 			ret = ttm_bo_reserve_slowpath(bo, intr, ticket);
 		}
 
-		if (!ret && entry->num_shared)
-			ret = dma_resv_reserve_shared(bo->base.resv,
-								entry->num_shared);
+		if (!ret)
+			ret = dma_resv_reserve_fences(bo->base.resv,
+						      num_fences);
 
 		if (unlikely(ret != 0)) {
 			if (ticket) {
diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
index 92bc0faee84f..961812d33827 100644
--- a/drivers/gpu/drm/v3d/v3d_gem.c
+++ b/drivers/gpu/drm/v3d/v3d_gem.c
@@ -259,16 +259,21 @@ v3d_lock_bo_reservations(struct v3d_job *job,
 		return ret;
 
 	for (i = 0; i < job->bo_count; i++) {
+		ret = dma_resv_reserve_fences(job->bo[i]->resv, 1);
+		if (ret)
+			goto fail;
+
 		ret = drm_sched_job_add_implicit_dependencies(&job->base,
 							      job->bo[i], true);
-		if (ret) {
-			drm_gem_unlock_reservations(job->bo, job->bo_count,
-						    acquire_ctx);
-			return ret;
-		}
+		if (ret)
+			goto fail;
 	}
 
 	return 0;
+
+fail:
+	drm_gem_unlock_reservations(job->bo, job->bo_count, acquire_ctx);
+	return ret;
 }
 
 /**
diff --git a/drivers/gpu/drm/vc4/vc4_gem.c b/drivers/gpu/drm/vc4/vc4_gem.c
index 4abf10b66fe8..594bd6bb00d2 100644
--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -644,7 +644,7 @@ retry:
 	for (i = 0; i < exec->bo_count; i++) {
 		bo = &exec->bo[i]->base;
 
-		ret = dma_resv_reserve_shared(bo->resv, 1);
+		ret = dma_resv_reserve_fences(bo->resv, 1);
 		if (ret) {
 			vc4_unlock_bo_reservations(dev, exec, acquire_ctx);
 			return ret;
diff --git a/drivers/gpu/drm/vgem/vgem_fence.c b/drivers/gpu/drm/vgem/vgem_fence.c
index bd6f75285fd9..2ddbebca87d9 100644
--- a/drivers/gpu/drm/vgem/vgem_fence.c
+++ b/drivers/gpu/drm/vgem/vgem_fence.c
@@ -157,12 +157,14 @@ int vgem_fence_attach_ioctl(struct drm_device *dev,
 	}
 
 	/* Expose the fence via the dma-buf */
-	ret = 0;
 	dma_resv_lock(resv, NULL);
-	if (arg->flags & VGEM_FENCE_WRITE)
-		dma_resv_add_excl_fence(resv, fence);
-	else if ((ret = dma_resv_reserve_shared(resv, 1)) == 0)
-		dma_resv_add_shared_fence(resv, fence);
+	ret = dma_resv_reserve_fences(resv, 1);
+	if (!ret) {
+		if (arg->flags & VGEM_FENCE_WRITE)
+			dma_resv_add_excl_fence(resv, fence);
+		else
+			dma_resv_add_shared_fence(resv, fence);
+	}
 	dma_resv_unlock(resv);
 
 	/* Record the fence in our idr for later signaling */
diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
index 48d3c9955f0d..1820ca6cf673 100644
--- a/drivers/gpu/drm/virtio/virtgpu_gem.c
+++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
@@ -214,6 +214,7 @@ void virtio_gpu_array_add_obj(struct virtio_gpu_object_array *objs,
 
 int virtio_gpu_array_lock_resv(struct virtio_gpu_object_array *objs)
 {
+	unsigned int i;
 	int ret;
 
 	if (objs->nents == 1) {
@@ -222,6 +223,14 @@ int virtio_gpu_array_lock_resv(struct virtio_gpu_object_array *objs)
 		ret = drm_gem_lock_reservations(objs->objs, objs->nents,
 						&objs->ticket);
 	}
+	if (ret)
+		return ret;
+
+	for (i = 0; i < objs->nents; ++i) {
+		ret = dma_resv_reserve_fences(objs->objs[i]->resv, 1);
+		if (ret)
+			return ret;
+	}
 	return ret;
 }
 
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
index 31aecc46624b..fe13aa8b4a64 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_bo.c
@@ -747,16 +747,22 @@ void vmw_bo_fence_single(struct ttm_buffer_object *bo,
 			 struct vmw_fence_obj *fence)
 {
 	struct ttm_device *bdev = bo->bdev;
-
 	struct vmw_private *dev_priv =
 		container_of(bdev, struct vmw_private, bdev);
+	int ret;
 
-	if (fence == NULL) {
+	if (fence == NULL)
 		vmw_execbuf_fence_commands(NULL, dev_priv, &fence, NULL);
+	else
+		dma_fence_get(&fence->base);
+
+	ret = dma_resv_reserve_fences(bo->base.resv, 1);
+	if (!ret)
 		dma_resv_add_excl_fence(bo->base.resv, &fence->base);
-		dma_fence_put(&fence->base);
-	} else
-		dma_resv_add_excl_fence(bo->base.resv, &fence->base);
+	else
+		/* Last resort fallback when we are OOM */
+		dma_fence_wait(&fence->base, false);
+	dma_fence_put(&fence->base);
 }
 
 
diff --git a/include/linux/dma-resv.h b/include/linux/dma-resv.h
index ecb697d4d861..5fa04d0fccad 100644
--- a/include/linux/dma-resv.h
+++ b/include/linux/dma-resv.h
@@ -117,7 +117,7 @@ struct dma_resv {
 	 * A new fence is added by calling dma_resv_add_shared_fence(). Since
 	 * this often needs to be done past the point of no return in command
 	 * submission it cannot fail, and therefore sufficient slots need to be
-	 * reserved by calling dma_resv_reserve_shared().
+	 * reserved by calling dma_resv_reserve_fences().
 	 *
 	 * Note that actual semantics of what an exclusive or shared fence mean
 	 * is defined by the user, for reservation objects shared across drivers
@@ -413,7 +413,7 @@ static inline void dma_resv_unlock(struct dma_resv *obj)
 
 void dma_resv_init(struct dma_resv *obj);
 void dma_resv_fini(struct dma_resv *obj);
-int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences);
+int dma_resv_reserve_fences(struct dma_resv *obj, unsigned int num_fences);
 void dma_resv_add_shared_fence(struct dma_resv *obj, struct dma_fence *fence);
 void dma_resv_replace_fences(struct dma_resv *obj, uint64_t context,
 			     struct dma_fence *fence);
-- 
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