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authorMaxime Ripard <maxime@cerno.tech>2022-04-05 12:38:33 +0300
committerMaxime Ripard <maxime@cerno.tech>2022-04-05 12:39:22 +0300
commit13043d1a12c54d8b6605bbead5e177e9fb98a287 (patch)
tree8dc499b9c583ae7d1efbfc050b639aaa686eafcd
parentcf5c5763eb531ff5120111ad300126e926fb5a56 (diff)
parent67bae5f28c895f8737a1974c3f31cf12b9170b14 (diff)
downloadlinux-13043d1a12c54d8b6605bbead5e177e9fb98a287.tar.xz
Merge drm-misc/drm-misc-next-fixes into drm-misc-fixes
There were a few patches left in drm-misc-next-fixes, let's bring them into drm-misc-fixes. Signed-off-by: Maxime Ripard <maxime@cerno.tech>
-rw-r--r--Documentation/driver-api/dma-buf.rst6
-rw-r--r--drivers/dma-buf/Makefile1
-rw-r--r--drivers/dma-buf/dma-fence-array.c32
-rw-r--r--drivers/dma-buf/selftests.h1
-rw-r--r--drivers/dma-buf/st-dma-fence-unwrap.c261
-rw-r--r--drivers/dma-buf/sync_file.c141
-rw-r--r--drivers/gpu/drm/drm_of.c99
-rw-r--r--include/linux/dma-fence-array.h19
-rw-r--r--include/linux/dma-fence-chain.h2
-rw-r--r--include/linux/dma-fence-unwrap.h95
10 files changed, 540 insertions, 117 deletions
diff --git a/Documentation/driver-api/dma-buf.rst b/Documentation/driver-api/dma-buf.rst
index 55006678394a..36a76cbe9095 100644
--- a/Documentation/driver-api/dma-buf.rst
+++ b/Documentation/driver-api/dma-buf.rst
@@ -185,6 +185,12 @@ DMA Fence Chain
.. kernel-doc:: include/linux/dma-fence-chain.h
:internal:
+DMA Fence unwrap
+~~~~~~~~~~~~~~~~
+
+.. kernel-doc:: include/linux/dma-fence-unwrap.h
+ :internal:
+
DMA Fence uABI/Sync File
~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
index 511805dbeb75..4c9eb53ba3f8 100644
--- a/drivers/dma-buf/Makefile
+++ b/drivers/dma-buf/Makefile
@@ -12,6 +12,7 @@ dmabuf_selftests-y := \
selftest.o \
st-dma-fence.o \
st-dma-fence-chain.o \
+ st-dma-fence-unwrap.o \
st-dma-resv.o
obj-$(CONFIG_DMABUF_SELFTESTS) += dmabuf_selftests.o
diff --git a/drivers/dma-buf/dma-fence-array.c b/drivers/dma-buf/dma-fence-array.c
index cb1bacb5a42b..5c8a7084577b 100644
--- a/drivers/dma-buf/dma-fence-array.c
+++ b/drivers/dma-buf/dma-fence-array.c
@@ -159,6 +159,8 @@ struct dma_fence_array *dma_fence_array_create(int num_fences,
struct dma_fence_array *array;
size_t size = sizeof(*array);
+ WARN_ON(!num_fences || !fences);
+
/* Allocate the callback structures behind the array. */
size += num_fences * sizeof(struct dma_fence_array_cb);
array = kzalloc(size, GFP_KERNEL);
@@ -219,3 +221,33 @@ bool dma_fence_match_context(struct dma_fence *fence, u64 context)
return true;
}
EXPORT_SYMBOL(dma_fence_match_context);
+
+struct dma_fence *dma_fence_array_first(struct dma_fence *head)
+{
+ struct dma_fence_array *array;
+
+ if (!head)
+ return NULL;
+
+ array = to_dma_fence_array(head);
+ if (!array)
+ return head;
+
+ if (!array->num_fences)
+ return NULL;
+
+ return array->fences[0];
+}
+EXPORT_SYMBOL(dma_fence_array_first);
+
+struct dma_fence *dma_fence_array_next(struct dma_fence *head,
+ unsigned int index)
+{
+ struct dma_fence_array *array = to_dma_fence_array(head);
+
+ if (!array || index >= array->num_fences)
+ return NULL;
+
+ return array->fences[index];
+}
+EXPORT_SYMBOL(dma_fence_array_next);
diff --git a/drivers/dma-buf/selftests.h b/drivers/dma-buf/selftests.h
index 97d73aaa31da..851965867d9c 100644
--- a/drivers/dma-buf/selftests.h
+++ b/drivers/dma-buf/selftests.h
@@ -12,4 +12,5 @@
selftest(sanitycheck, __sanitycheck__) /* keep first (igt selfcheck) */
selftest(dma_fence, dma_fence)
selftest(dma_fence_chain, dma_fence_chain)
+selftest(dma_fence_unwrap, dma_fence_unwrap)
selftest(dma_resv, dma_resv)
diff --git a/drivers/dma-buf/st-dma-fence-unwrap.c b/drivers/dma-buf/st-dma-fence-unwrap.c
new file mode 100644
index 000000000000..039f016b57be
--- /dev/null
+++ b/drivers/dma-buf/st-dma-fence-unwrap.c
@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: MIT
+
+/*
+ * Copyright (C) 2022 Advanced Micro Devices, Inc.
+ */
+
+#include <linux/dma-fence-unwrap.h>
+#if 0
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/random.h>
+#endif
+
+#include "selftest.h"
+
+#define CHAIN_SZ (4 << 10)
+
+static inline struct mock_fence {
+ struct dma_fence base;
+ spinlock_t lock;
+} *to_mock_fence(struct dma_fence *f) {
+ return container_of(f, struct mock_fence, base);
+}
+
+static const char *mock_name(struct dma_fence *f)
+{
+ return "mock";
+}
+
+static const struct dma_fence_ops mock_ops = {
+ .get_driver_name = mock_name,
+ .get_timeline_name = mock_name,
+};
+
+static struct dma_fence *mock_fence(void)
+{
+ struct mock_fence *f;
+
+ f = kmalloc(sizeof(*f), GFP_KERNEL);
+ if (!f)
+ return NULL;
+
+ spin_lock_init(&f->lock);
+ dma_fence_init(&f->base, &mock_ops, &f->lock, 0, 0);
+
+ return &f->base;
+}
+
+static struct dma_fence *mock_array(unsigned int num_fences, ...)
+{
+ struct dma_fence_array *array;
+ struct dma_fence **fences;
+ va_list valist;
+ int i;
+
+ fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL);
+ if (!fences)
+ return NULL;
+
+ va_start(valist, num_fences);
+ for (i = 0; i < num_fences; ++i)
+ fences[i] = va_arg(valist, typeof(*fences));
+ va_end(valist);
+
+ array = dma_fence_array_create(num_fences, fences,
+ dma_fence_context_alloc(1),
+ 1, false);
+ if (!array)
+ goto cleanup;
+ return &array->base;
+
+cleanup:
+ for (i = 0; i < num_fences; ++i)
+ dma_fence_put(fences[i]);
+ kfree(fences);
+ return NULL;
+}
+
+static struct dma_fence *mock_chain(struct dma_fence *prev,
+ struct dma_fence *fence)
+{
+ struct dma_fence_chain *f;
+
+ f = dma_fence_chain_alloc();
+ if (!f) {
+ dma_fence_put(prev);
+ dma_fence_put(fence);
+ return NULL;
+ }
+
+ dma_fence_chain_init(f, prev, fence, 1);
+ return &f->base;
+}
+
+static int sanitycheck(void *arg)
+{
+ struct dma_fence *f, *chain, *array;
+ int err = 0;
+
+ f = mock_fence();
+ if (!f)
+ return -ENOMEM;
+
+ array = mock_array(1, f);
+ if (!array)
+ return -ENOMEM;
+
+ chain = mock_chain(NULL, array);
+ if (!chain)
+ return -ENOMEM;
+
+ dma_fence_signal(f);
+ dma_fence_put(chain);
+ return err;
+}
+
+static int unwrap_array(void *arg)
+{
+ struct dma_fence *fence, *f1, *f2, *array;
+ struct dma_fence_unwrap iter;
+ int err = 0;
+
+ f1 = mock_fence();
+ if (!f1)
+ return -ENOMEM;
+
+ f2 = mock_fence();
+ if (!f2) {
+ dma_fence_put(f1);
+ return -ENOMEM;
+ }
+
+ array = mock_array(2, f1, f2);
+ if (!array)
+ return -ENOMEM;
+
+ dma_fence_unwrap_for_each(fence, &iter, array) {
+ if (fence == f1) {
+ f1 = NULL;
+ } else if (fence == f2) {
+ f2 = NULL;
+ } else {
+ pr_err("Unexpected fence!\n");
+ err = -EINVAL;
+ }
+ }
+
+ if (f1 || f2) {
+ pr_err("Not all fences seen!\n");
+ err = -EINVAL;
+ }
+
+ dma_fence_signal(f1);
+ dma_fence_signal(f2);
+ dma_fence_put(array);
+ return 0;
+}
+
+static int unwrap_chain(void *arg)
+{
+ struct dma_fence *fence, *f1, *f2, *chain;
+ struct dma_fence_unwrap iter;
+ int err = 0;
+
+ f1 = mock_fence();
+ if (!f1)
+ return -ENOMEM;
+
+ f2 = mock_fence();
+ if (!f2) {
+ dma_fence_put(f1);
+ return -ENOMEM;
+ }
+
+ chain = mock_chain(f1, f2);
+ if (!chain)
+ return -ENOMEM;
+
+ dma_fence_unwrap_for_each(fence, &iter, chain) {
+ if (fence == f1) {
+ f1 = NULL;
+ } else if (fence == f2) {
+ f2 = NULL;
+ } else {
+ pr_err("Unexpected fence!\n");
+ err = -EINVAL;
+ }
+ }
+
+ if (f1 || f2) {
+ pr_err("Not all fences seen!\n");
+ err = -EINVAL;
+ }
+
+ dma_fence_signal(f1);
+ dma_fence_signal(f2);
+ dma_fence_put(chain);
+ return 0;
+}
+
+static int unwrap_chain_array(void *arg)
+{
+ struct dma_fence *fence, *f1, *f2, *array, *chain;
+ struct dma_fence_unwrap iter;
+ int err = 0;
+
+ f1 = mock_fence();
+ if (!f1)
+ return -ENOMEM;
+
+ f2 = mock_fence();
+ if (!f2) {
+ dma_fence_put(f1);
+ return -ENOMEM;
+ }
+
+ array = mock_array(2, f1, f2);
+ if (!array)
+ return -ENOMEM;
+
+ chain = mock_chain(NULL, array);
+ if (!chain)
+ return -ENOMEM;
+
+ dma_fence_unwrap_for_each(fence, &iter, chain) {
+ if (fence == f1) {
+ f1 = NULL;
+ } else if (fence == f2) {
+ f2 = NULL;
+ } else {
+ pr_err("Unexpected fence!\n");
+ err = -EINVAL;
+ }
+ }
+
+ if (f1 || f2) {
+ pr_err("Not all fences seen!\n");
+ err = -EINVAL;
+ }
+
+ dma_fence_signal(f1);
+ dma_fence_signal(f2);
+ dma_fence_put(chain);
+ return 0;
+}
+
+int dma_fence_unwrap(void)
+{
+ static const struct subtest tests[] = {
+ SUBTEST(sanitycheck),
+ SUBTEST(unwrap_array),
+ SUBTEST(unwrap_chain),
+ SUBTEST(unwrap_chain_array),
+ };
+
+ return subtests(tests, NULL);
+}
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index 394e6e1e9686..514d213261df 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -5,6 +5,7 @@
* Copyright (C) 2012 Google, Inc.
*/
+#include <linux/dma-fence-unwrap.h>
#include <linux/export.h>
#include <linux/file.h>
#include <linux/fs.h>
@@ -172,20 +173,6 @@ static int sync_file_set_fence(struct sync_file *sync_file,
return 0;
}
-static struct dma_fence **get_fences(struct sync_file *sync_file,
- int *num_fences)
-{
- if (dma_fence_is_array(sync_file->fence)) {
- struct dma_fence_array *array = to_dma_fence_array(sync_file->fence);
-
- *num_fences = array->num_fences;
- return array->fences;
- }
-
- *num_fences = 1;
- return &sync_file->fence;
-}
-
static void add_fence(struct dma_fence **fences,
int *i, struct dma_fence *fence)
{
@@ -210,86 +197,97 @@ static void add_fence(struct dma_fence **fences,
static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
struct sync_file *b)
{
+ struct dma_fence *a_fence, *b_fence, **fences;
+ struct dma_fence_unwrap a_iter, b_iter;
+ unsigned int index, num_fences;
struct sync_file *sync_file;
- struct dma_fence **fences = NULL, **nfences, **a_fences, **b_fences;
- int i = 0, i_a, i_b, num_fences, a_num_fences, b_num_fences;
sync_file = sync_file_alloc();
if (!sync_file)
return NULL;
- a_fences = get_fences(a, &a_num_fences);
- b_fences = get_fences(b, &b_num_fences);
- if (a_num_fences > INT_MAX - b_num_fences)
- goto err;
+ num_fences = 0;
+ dma_fence_unwrap_for_each(a_fence, &a_iter, a->fence)
+ ++num_fences;
+ dma_fence_unwrap_for_each(b_fence, &b_iter, b->fence)
+ ++num_fences;
- num_fences = a_num_fences + b_num_fences;
+ if (num_fences > INT_MAX)
+ goto err_free_sync_file;
fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL);
if (!fences)
- goto err;
+ goto err_free_sync_file;
/*
- * Assume sync_file a and b are both ordered and have no
- * duplicates with the same context.
+ * We can't guarantee that fences in both a and b are ordered, but it is
+ * still quite likely.
*
- * If a sync_file can only be created with sync_file_merge
- * and sync_file_create, this is a reasonable assumption.
+ * So attempt to order the fences as we pass over them and merge fences
+ * with the same context.
*/
- for (i_a = i_b = 0; i_a < a_num_fences && i_b < b_num_fences; ) {
- struct dma_fence *pt_a = a_fences[i_a];
- struct dma_fence *pt_b = b_fences[i_b];
- if (pt_a->context < pt_b->context) {
- add_fence(fences, &i, pt_a);
+ index = 0;
+ for (a_fence = dma_fence_unwrap_first(a->fence, &a_iter),
+ b_fence = dma_fence_unwrap_first(b->fence, &b_iter);
+ a_fence || b_fence; ) {
+
+ if (!b_fence) {
+ add_fence(fences, &index, a_fence);
+ a_fence = dma_fence_unwrap_next(&a_iter);
+
+ } else if (!a_fence) {
+ add_fence(fences, &index, b_fence);
+ b_fence = dma_fence_unwrap_next(&b_iter);
+
+ } else if (a_fence->context < b_fence->context) {
+ add_fence(fences, &index, a_fence);
+ a_fence = dma_fence_unwrap_next(&a_iter);
- i_a++;
- } else if (pt_a->context > pt_b->context) {
- add_fence(fences, &i, pt_b);
+ } else if (b_fence->context < a_fence->context) {
+ add_fence(fences, &index, b_fence);
+ b_fence = dma_fence_unwrap_next(&b_iter);
+
+ } else if (__dma_fence_is_later(a_fence->seqno, b_fence->seqno,
+ a_fence->ops)) {
+ add_fence(fences, &index, a_fence);
+ a_fence = dma_fence_unwrap_next(&a_iter);
+ b_fence = dma_fence_unwrap_next(&b_iter);
- i_b++;
} else {
- if (__dma_fence_is_later(pt_a->seqno, pt_b->seqno,
- pt_a->ops))
- add_fence(fences, &i, pt_a);
- else
- add_fence(fences, &i, pt_b);
-
- i_a++;
- i_b++;
+ add_fence(fences, &index, b_fence);
+ a_fence = dma_fence_unwrap_next(&a_iter);
+ b_fence = dma_fence_unwrap_next(&b_iter);
}
}
- for (; i_a < a_num_fences; i_a++)
- add_fence(fences, &i, a_fences[i_a]);
-
- for (; i_b < b_num_fences; i_b++)
- add_fence(fences, &i, b_fences[i_b]);
-
- if (i == 0)
- fences[i++] = dma_fence_get(a_fences[0]);
+ if (index == 0)
+ fences[index++] = dma_fence_get_stub();
- if (num_fences > i) {
- nfences = krealloc_array(fences, i, sizeof(*fences), GFP_KERNEL);
- if (!nfences)
- goto err;
+ if (num_fences > index) {
+ struct dma_fence **tmp;
- fences = nfences;
+ /* Keep going even when reducing the size failed */
+ tmp = krealloc_array(fences, index, sizeof(*fences),
+ GFP_KERNEL);
+ if (tmp)
+ fences = tmp;
}
- if (sync_file_set_fence(sync_file, fences, i) < 0)
- goto err;
+ if (sync_file_set_fence(sync_file, fences, index) < 0)
+ goto err_put_fences;
strlcpy(sync_file->user_name, name, sizeof(sync_file->user_name));
return sync_file;
-err:
- while (i)
- dma_fence_put(fences[--i]);
+err_put_fences:
+ while (index)
+ dma_fence_put(fences[--index]);
kfree(fences);
+
+err_free_sync_file:
fput(sync_file->file);
return NULL;
-
}
static int sync_file_release(struct inode *inode, struct file *file)
@@ -398,11 +396,13 @@ static int sync_fill_fence_info(struct dma_fence *fence,
static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
unsigned long arg)
{
- struct sync_file_info info;
struct sync_fence_info *fence_info = NULL;
- struct dma_fence **fences;
+ struct dma_fence_unwrap iter;
+ struct sync_file_info info;
+ unsigned int num_fences;
+ struct dma_fence *fence;
+ int ret;
__u32 size;
- int num_fences, ret, i;
if (copy_from_user(&info, (void __user *)arg, sizeof(info)))
return -EFAULT;
@@ -410,7 +410,9 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
if (info.flags || info.pad)
return -EINVAL;
- fences = get_fences(sync_file, &num_fences);
+ num_fences = 0;
+ dma_fence_unwrap_for_each(fence, &iter, sync_file->fence)
+ ++num_fences;
/*
* Passing num_fences = 0 means that userspace doesn't want to
@@ -433,8 +435,11 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
if (!fence_info)
return -ENOMEM;
- for (i = 0; i < num_fences; i++) {
- int status = sync_fill_fence_info(fences[i], &fence_info[i]);
+ num_fences = 0;
+ dma_fence_unwrap_for_each(fence, &iter, sync_file->fence) {
+ int status;
+
+ status = sync_fill_fence_info(fence, &fence_info[num_fences++]);
info.status = info.status <= 0 ? info.status : status;
}
diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
index 026e4e29a0f3..f4df344509a8 100644
--- a/drivers/gpu/drm/drm_of.c
+++ b/drivers/gpu/drm/drm_of.c
@@ -214,6 +214,29 @@ int drm_of_encoder_active_endpoint(struct device_node *node,
}
EXPORT_SYMBOL_GPL(drm_of_encoder_active_endpoint);
+static int find_panel_or_bridge(struct device_node *node,
+ struct drm_panel **panel,
+ struct drm_bridge **bridge)
+{
+ if (panel) {
+ *panel = of_drm_find_panel(node);
+ if (!IS_ERR(*panel))
+ return 0;
+
+ /* Clear the panel pointer in case of error. */
+ *panel = NULL;
+ }
+
+ /* No panel found yet, check for a bridge next. */
+ if (bridge) {
+ *bridge = of_drm_find_bridge(node);
+ if (*bridge)
+ return 0;
+ }
+
+ return -EPROBE_DEFER;
+}
+
/**
* drm_of_find_panel_or_bridge - return connected panel or bridge device
* @np: device tree node containing encoder output ports
@@ -236,66 +259,44 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
struct drm_panel **panel,
struct drm_bridge **bridge)
{
- int ret = -EPROBE_DEFER;
- struct device_node *remote;
+ struct device_node *node;
+ int ret;
if (!panel && !bridge)
return -EINVAL;
+
if (panel)
*panel = NULL;
-
- /**
- * Devices can also be child nodes when we also control that device
- * through the upstream device (ie, MIPI-DCS for a MIPI-DSI device).
- *
- * Lookup for a child node of the given parent that isn't either port
- * or ports.
- */
- for_each_available_child_of_node(np, remote) {
- if (of_node_name_eq(remote, "port") ||
- of_node_name_eq(remote, "ports"))
- continue;
-
- goto of_find_panel_or_bridge;
+ if (bridge)
+ *bridge = NULL;
+
+ /* Check for a graph on the device node first. */
+ if (of_graph_is_present(np)) {
+ node = of_graph_get_remote_node(np, port, endpoint);
+ if (node) {
+ ret = find_panel_or_bridge(node, panel, bridge);
+ of_node_put(node);
+
+ if (!ret)
+ return 0;
+ }
}
- /*
- * of_graph_get_remote_node() produces a noisy error message if port
- * node isn't found and the absence of the port is a legit case here,
- * so at first we silently check whether graph presents in the
- * device-tree node.
- */
- if (!of_graph_is_present(np))
- return -ENODEV;
-
- remote = of_graph_get_remote_node(np, port, endpoint);
-
-of_find_panel_or_bridge:
- if (!remote)
- return -ENODEV;
+ /* Otherwise check for any child node other than port/ports. */
+ for_each_available_child_of_node(np, node) {
+ if (of_node_name_eq(node, "port") ||
+ of_node_name_eq(node, "ports"))
+ continue;
- if (panel) {
- *panel = of_drm_find_panel(remote);
- if (!IS_ERR(*panel))
- ret = 0;
- else
- *panel = NULL;
- }
-
- /* No panel found yet, check for a bridge next. */
- if (bridge) {
- if (ret) {
- *bridge = of_drm_find_bridge(remote);
- if (*bridge)
- ret = 0;
- } else {
- *bridge = NULL;
- }
+ ret = find_panel_or_bridge(node, panel, bridge);
+ of_node_put(node);
+ /* Stop at the first found occurrence. */
+ if (!ret)
+ return 0;
}
- of_node_put(remote);
- return ret;
+ return -EPROBE_DEFER;
}
EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge);
diff --git a/include/linux/dma-fence-array.h b/include/linux/dma-fence-array.h
index fec374f69e12..ec7f25def392 100644
--- a/include/linux/dma-fence-array.h
+++ b/include/linux/dma-fence-array.h
@@ -61,6 +61,21 @@ to_dma_fence_array(struct dma_fence *fence)
return container_of(fence, struct dma_fence_array, base);
}
+/**
+ * dma_fence_array_for_each - iterate over all fences in array
+ * @fence: current fence
+ * @index: index into the array
+ * @head: potential dma_fence_array object
+ *
+ * Test if @array is a dma_fence_array object and if yes iterate over all fences
+ * in the array. If not just iterate over the fence in @array itself.
+ *
+ * For a deep dive iterator see dma_fence_unwrap_for_each().
+ */
+#define dma_fence_array_for_each(fence, index, head) \
+ for (index = 0, fence = dma_fence_array_first(head); fence; \
+ ++(index), fence = dma_fence_array_next(head, index))
+
struct dma_fence_array *dma_fence_array_create(int num_fences,
struct dma_fence **fences,
u64 context, unsigned seqno,
@@ -68,4 +83,8 @@ struct dma_fence_array *dma_fence_array_create(int num_fences,
bool dma_fence_match_context(struct dma_fence *fence, u64 context);
+struct dma_fence *dma_fence_array_first(struct dma_fence *head);
+struct dma_fence *dma_fence_array_next(struct dma_fence *head,
+ unsigned int index);
+
#endif /* __LINUX_DMA_FENCE_ARRAY_H */
diff --git a/include/linux/dma-fence-chain.h b/include/linux/dma-fence-chain.h
index 10d51bcdf7b7..4bdf0b96da28 100644
--- a/include/linux/dma-fence-chain.h
+++ b/include/linux/dma-fence-chain.h
@@ -112,6 +112,8 @@ static inline void dma_fence_chain_free(struct dma_fence_chain *chain)
*
* Iterate over all fences in the chain. We keep a reference to the current
* fence while inside the loop which must be dropped when breaking out.
+ *
+ * For a deep dive iterator see dma_fence_unwrap_for_each().
*/
#define dma_fence_chain_for_each(iter, head) \
for (iter = dma_fence_get(head); iter; \
diff --git a/include/linux/dma-fence-unwrap.h b/include/linux/dma-fence-unwrap.h
new file mode 100644
index 000000000000..77e335a1bcac
--- /dev/null
+++ b/include/linux/dma-fence-unwrap.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * fence-chain: chain fences together in a timeline
+ *
+ * Copyright (C) 2022 Advanced Micro Devices, Inc.
+ * Authors:
+ * Christian König <christian.koenig@amd.com>
+ */
+
+#ifndef __LINUX_DMA_FENCE_UNWRAP_H
+#define __LINUX_DMA_FENCE_UNWRAP_H
+
+#include <linux/dma-fence-chain.h>
+#include <linux/dma-fence-array.h>
+
+/**
+ * struct dma_fence_unwrap - cursor into the container structure
+ *
+ * Should be used with dma_fence_unwrap_for_each() iterator macro.
+ */
+struct dma_fence_unwrap {
+ /**
+ * @chain: potential dma_fence_chain, but can be other fence as well
+ */
+ struct dma_fence *chain;
+ /**
+ * @array: potential dma_fence_array, but can be other fence as well
+ */
+ struct dma_fence *array;
+ /**
+ * @index: last returned index if @array is really a dma_fence_array
+ */
+ unsigned int index;
+};
+
+/* Internal helper to start new array iteration, don't use directly */
+static inline struct dma_fence *
+__dma_fence_unwrap_array(struct dma_fence_unwrap * cursor)
+{
+ cursor->array = dma_fence_chain_contained(cursor->chain);
+ cursor->index = 0;
+ return dma_fence_array_first(cursor->array);
+}
+
+/**
+ * dma_fence_unwrap_first - return the first fence from fence containers
+ * @head: the entrypoint into the containers
+ * @cursor: current position inside the containers
+ *
+ * Unwraps potential dma_fence_chain/dma_fence_array containers and return the
+ * first fence.
+ */
+static inline struct dma_fence *
+dma_fence_unwrap_first(struct dma_fence *head, struct dma_fence_unwrap *cursor)
+{
+ cursor->chain = dma_fence_get(head);
+ return __dma_fence_unwrap_array(cursor);
+}
+
+/**
+ * dma_fence_unwrap_next - return the next fence from a fence containers
+ * @cursor: current position inside the containers
+ *
+ * Continue unwrapping the dma_fence_chain/dma_fence_array containers and return
+ * the next fence from them.
+ */
+static inline struct dma_fence *
+dma_fence_unwrap_next(struct dma_fence_unwrap *cursor)
+{
+ struct dma_fence *tmp;
+
+ ++cursor->index;
+ tmp = dma_fence_array_next(cursor->array, cursor->index);
+ if (tmp)
+ return tmp;
+
+ cursor->chain = dma_fence_chain_walk(cursor->chain);
+ return __dma_fence_unwrap_array(cursor);
+}
+
+/**
+ * dma_fence_unwrap_for_each - iterate over all fences in containers
+ * @fence: current fence
+ * @cursor: current position inside the containers
+ * @head: starting point for the iterator
+ *
+ * Unwrap dma_fence_chain and dma_fence_array containers and deep dive into all
+ * potential fences in them. If @head is just a normal fence only that one is
+ * returned.
+ */
+#define dma_fence_unwrap_for_each(fence, cursor, head) \
+ for (fence = dma_fence_unwrap_first(head, cursor); fence; \
+ fence = dma_fence_unwrap_next(cursor))
+
+#endif