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authorGustavo Padovan <gustavo.padovan@collabora.co.uk>2016-06-01 15:10:03 +0200
committerDaniel Vetter <daniel.vetter@ffwll.ch>2016-06-02 09:26:15 +0200
commitb3dfbdf261e076a997f812323edfdba84ba80256 (patch)
tree06bf2fdb5d65c62aee083ae7867e45394def663e
parent76bf0db5543976ef50362db7071da367cb118532 (diff)
dma-buf/fence: add fence_array fences v6
struct fence_array inherits from struct fence and carries a collection of fences that needs to be waited together. It is useful to translate a sync_file to a fence to remove the complexity of dealing with sync_files on DRM drivers. So even if there are many fences in the sync_file that needs to waited for a commit to happen, they all get added to the fence_collection and passed for DRM use as a standard struct fence. That means that no changes needed to any driver besides supporting fences. To avoid fence_array's fence allocates a new timeline if needed (when combining fences from different timelines). v2: Comments by Daniel Vetter: - merge fence_collection_init() and fence_collection_add() - only add callbacks at ->enable_signalling() - remove fence_collection_put() - check for type on to_fence_collection() - adjust fence_is_later() and fence_later() to WARN_ON() if they are used with collection fences. v3: - Initialize fence_cb.node at fence init. Comments by Chris Wilson: - return "unbound" on fence_collection_get_timeline_name() - don't stop adding callbacks if one fails - remove redundant !! on fence_collection_enable_signaling() - remove redundant () on fence_collection_signaled - use fence_default_wait() instead v4 (chk): Rework, simplification and cleanup: - Drop FENCE_NO_CONTEXT handling, always allocate a context. - Rename to fence_array. - Return fixed driver name. - Register only one callback at a time. - Document that create function takes ownership of array. v5 (chk): More work and fixes: - Avoid deadlocks by adding all callbacks at once again. - Stop trying to remove the callbacks. - Provide context and sequence number for the array fence. v6 (chk): Fixes found during testing - Fix stupid typo in _enable_signaling(). Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk> Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk> Acked-by: Sumit Semwal <sumit.semwal@linaro.org> [danvet: Improve commit message as suggested by Gustavo.] Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1464786612-5010-3-git-send-email-deathsimple@vodafone.de
-rw-r--r--drivers/dma-buf/Makefile2
-rw-r--r--drivers/dma-buf/fence-array.c127
-rw-r--r--include/linux/fence-array.h72
3 files changed, 200 insertions, 1 deletions
diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
index 4a424ec..f353db2 100644
--- a/drivers/dma-buf/Makefile
+++ b/drivers/dma-buf/Makefile
@@ -1,2 +1,2 @@
-obj-y := dma-buf.o fence.o reservation.o seqno-fence.o
+obj-y := dma-buf.o fence.o reservation.o seqno-fence.o fence-array.o
obj-$(CONFIG_SYNC_FILE) += sync_file.o
diff --git a/drivers/dma-buf/fence-array.c b/drivers/dma-buf/fence-array.c
new file mode 100644
index 0000000..8141217
--- /dev/null
+++ b/drivers/dma-buf/fence-array.c
@@ -0,0 +1,127 @@
+/*
+ * fence-array: aggregate fences to be waited together
+ *
+ * Copyright (C) 2016 Collabora Ltd
+ * Copyright (C) 2016 Advanced Micro Devices, Inc.
+ * Authors:
+ * Gustavo Padovan <gustavo@padovan.org>
+ * Christian König <christian.koenig@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/fence-array.h>
+
+static void fence_array_cb_func(struct fence *f, struct fence_cb *cb);
+
+static const char *fence_array_get_driver_name(struct fence *fence)
+{
+ return "fence_array";
+}
+
+static const char *fence_array_get_timeline_name(struct fence *fence)
+{
+ return "unbound";
+}
+
+static void fence_array_cb_func(struct fence *f, struct fence_cb *cb)
+{
+ struct fence_array_cb *array_cb =
+ container_of(cb, struct fence_array_cb, cb);
+ struct fence_array *array = array_cb->array;
+
+ if (atomic_dec_and_test(&array->num_pending))
+ fence_signal(&array->base);
+}
+
+static bool fence_array_enable_signaling(struct fence *fence)
+{
+ struct fence_array *array = to_fence_array(fence);
+ struct fence_array_cb *cb = (void *)(&array[1]);
+ unsigned i;
+
+ for (i = 0; i < array->num_fences; ++i) {
+ cb[i].array = array;
+ if (fence_add_callback(array->fences[i], &cb[i].cb,
+ fence_array_cb_func))
+ if (atomic_dec_and_test(&array->num_pending))
+ return false;
+ }
+
+ return true;
+}
+
+static bool fence_array_signaled(struct fence *fence)
+{
+ struct fence_array *array = to_fence_array(fence);
+
+ return atomic_read(&array->num_pending) == 0;
+}
+
+static void fence_array_release(struct fence *fence)
+{
+ struct fence_array *array = to_fence_array(fence);
+ unsigned i;
+
+ for (i = 0; i < array->num_fences; ++i)
+ fence_put(array->fences[i]);
+
+ kfree(array->fences);
+ fence_free(fence);
+}
+
+const struct fence_ops fence_array_ops = {
+ .get_driver_name = fence_array_get_driver_name,
+ .get_timeline_name = fence_array_get_timeline_name,
+ .enable_signaling = fence_array_enable_signaling,
+ .signaled = fence_array_signaled,
+ .wait = fence_default_wait,
+ .release = fence_array_release,
+};
+
+/**
+ * fence_array_create - Create a custom fence array
+ * @num_fences: [in] number of fences to add in the array
+ * @fences: [in] array containing the fences
+ * @context: [in] fence context to use
+ * @seqno: [in] sequence number to use
+ *
+ * Allocate a fence_array object and initialize the base fence with fence_init().
+ * In case of error it returns NULL.
+ *
+ * The caller should allocte the fences array with num_fences size
+ * and fill it with the fences it wants to add to the object. Ownership of this
+ * array is take and fence_put() is used on each fence on release.
+ */
+struct fence_array *fence_array_create(int num_fences, struct fence **fences,
+ u64 context, unsigned seqno)
+{
+ struct fence_array *array;
+ size_t size = sizeof(*array);
+
+ /* Allocate the callback structures behind the array. */
+ size += num_fences * sizeof(struct fence_array_cb);
+ array = kzalloc(size, GFP_KERNEL);
+ if (!array)
+ return NULL;
+
+ spin_lock_init(&array->lock);
+ fence_init(&array->base, &fence_array_ops, &array->lock,
+ context, seqno);
+
+ array->num_fences = num_fences;
+ atomic_set(&array->num_pending, num_fences);
+ array->fences = fences;
+
+ return array;
+}
+EXPORT_SYMBOL(fence_array_create);
diff --git a/include/linux/fence-array.h b/include/linux/fence-array.h
new file mode 100644
index 0000000..593ab98
--- /dev/null
+++ b/include/linux/fence-array.h
@@ -0,0 +1,72 @@
+/*
+ * fence-array: aggregates fence to be waited together
+ *
+ * Copyright (C) 2016 Collabora Ltd
+ * Copyright (C) 2016 Advanced Micro Devices, Inc.
+ * Authors:
+ * Gustavo Padovan <gustavo@padovan.org>
+ * Christian König <christian.koenig@amd.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef __LINUX_FENCE_ARRAY_H
+#define __LINUX_FENCE_ARRAY_H
+
+#include <linux/fence.h>
+
+/**
+ * struct fence_array_cb - callback helper for fence array
+ * @cb: fence callback structure for signaling
+ * @array: reference to the parent fence array object
+ */
+struct fence_array_cb {
+ struct fence_cb cb;
+ struct fence_array *array;
+};
+
+/**
+ * struct fence_array - fence to represent an array of fences
+ * @base: fence base class
+ * @lock: spinlock for fence handling
+ * @num_fences: number of fences in the array
+ * @num_pending: fences in the array still pending
+ * @fences: array of the fences
+ */
+struct fence_array {
+ struct fence base;
+
+ spinlock_t lock;
+ unsigned num_fences;
+ atomic_t num_pending;
+ struct fence **fences;
+};
+
+extern const struct fence_ops fence_array_ops;
+
+/**
+ * to_fence_array - cast a fence to a fence_array
+ * @fence: fence to cast to a fence_array
+ *
+ * Returns NULL if the fence is not a fence_array,
+ * or the fence_array otherwise.
+ */
+static inline struct fence_array *to_fence_array(struct fence *fence)
+{
+ if (fence->ops != &fence_array_ops)
+ return NULL;
+
+ return container_of(fence, struct fence_array, base);
+}
+
+struct fence_array *fence_array_create(int num_fences, struct fence **fences,
+ u64 context, unsigned seqno);
+
+#endif /* __LINUX_FENCE_ARRAY_H */