[PATCH 08/22] drm: Add drm_dynarray

[ville.syrjala@linux.intel.com]

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Add a small helper that gives us dynamically growing arrays. We have a
couple hand rolled implementations of this in the atomic code, which we
can unify to use a common implementation.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 Documentation/gpu/drm-utils.rst | 15 +++++++
 Documentation/gpu/index.rst     |  1 +
 drivers/gpu/drm/Makefile        |  2 +-
 drivers/gpu/drm/drm_dynarray.c  | 97 +++++++++++++++++++++++++++++++++++++++++
 include/drm/drm_dynarray.h      | 54 +++++++++++++++++++++++
 5 files changed, 168 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/gpu/drm-utils.rst
 create mode 100644 drivers/gpu/drm/drm_dynarray.c
 create mode 100644 include/drm/drm_dynarray.h

diff --git a/Documentation/gpu/drm-utils.rst b/Documentation/gpu/drm-utils.rst
new file mode 100644
index 000000000000..bff8c899d7cd
--- /dev/null
+++ b/Documentation/gpu/drm-utils.rst
@@ -0,0 +1,15 @@
+=============
+DRM Utilities
+=============
+
+Dynamic arrays
+--------------
+
+.. kernel-doc:: drivers/gpu/drm/drm_dynarray.c
+   :doc: Dynamic arrays
+
+.. kernel-doc:: drivers/gpu/drm/drm_dynarray.c
+   :export:
+
+.. kernel-doc:: include/drm/drm_dynarray.h
+   :internal:
diff --git a/Documentation/gpu/index.rst b/Documentation/gpu/index.rst
index 35d673bf9b56..b7d196e5c70d 100644
--- a/Documentation/gpu/index.rst
+++ b/Documentation/gpu/index.rst
@@ -10,6 +10,7 @@ Linux GPU Driver Developer's Guide
    drm-kms
    drm-kms-helpers
    drm-uapi
+   drm-utils
    i915
    meson
    pl111
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 24a066e1841c..b637a34df388 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -3,7 +3,7 @@
 # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
 
 drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
-		drm_context.o drm_dma.o \
+		drm_context.o drm_dma.o drm_dynarray.o \
 		drm_file.o drm_gem.o drm_ioctl.o drm_irq.o \
 		drm_lock.o drm_memory.o drm_drv.o \
 		drm_scatter.o drm_pci.o \
diff --git a/drivers/gpu/drm/drm_dynarray.c b/drivers/gpu/drm/drm_dynarray.c
new file mode 100644
index 000000000000..69a8819ecb62
--- /dev/null
+++ b/drivers/gpu/drm/drm_dynarray.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2017 Intel Corp.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <drm/drm_dynarray.h>
+
+/**
+ * DOC: Dynamic arrays
+ *
+ * Helper that provides dynamically growing arrays. The array
+ * must be initilaized to specify the size of each element, and
+ * space can be reserved in the array by specifying the element
+ * index to be used.
+ */
+
+/**
+ * drm_dynarray_init - Initialize the dynamic array
+ * @dynarr: the dynamic array
+ * @elem_size: size of each element in bytes
+ *
+ * Initialize the dynamic array and specify the size of
+ * each element of the array.
+ */
+void drm_dynarray_init(struct drm_dynarray *dynarr,
+		       unsigned int elem_size)
+{
+	memset(dynarr, 0, sizeof(*dynarr));
+	dynarr->elem_size = elem_size;
+}
+EXPORT_SYMBOL(drm_dynarray_init);
+
+/**
+ * drm_dynarray_fini - Finalize the dynamic array
+ * @dynarr: the dynamic array
+ *
+ * Finalize the dynamic array, ie. free the memory
+ * used by the array.
+ */
+void drm_dynarray_fini(struct drm_dynarray *dynarr)
+{
+	kfree(dynarr->elems);
+	memset(dynarr, 0, sizeof(*dynarr));
+}
+EXPORT_SYMBOL(drm_dynarray_fini);
+
+/**
+ * drm_dynarray_reserve - Reserve space in the dynamic array
+ * @dynarr: the dynamic array
+ * @index: the index of the element to reserve
+ *
+ * Grow the array sufficiently to make sure @index points
+ * to a valid memory location within the array.
+ */
+int drm_dynarray_reserve(struct drm_dynarray *dynarr,
+			 unsigned int index)
+{
+	unsigned int num_elems = index + 1;
+	unsigned int old_num_elems = dynarr->num_elems;
+	void *elems;
+
+	if (num_elems <= old_num_elems)
+		return 0;
+
+	elems = krealloc(dynarr->elems,
+			 num_elems * dynarr->elem_size, GFP_KERNEL);
+	if (!elems)
+		return -ENOMEM;
+
+	dynarr->elems = elems;
+	dynarr->num_elems = num_elems;
+
+	memset(drm_dynarray_elem(dynarr, old_num_elems), 0,
+	       (num_elems - old_num_elems) * dynarr->elem_size);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dynarray_reserve);
diff --git a/include/drm/drm_dynarray.h b/include/drm/drm_dynarray.h
new file mode 100644
index 000000000000..c8cd088a3a3b
--- /dev/null
+++ b/include/drm/drm_dynarray.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2017 Intel Corp.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef DRM_DYNARRAY_H
+#define DRM_DYNARRAY_H
+
+struct drm_dynarray {
+	void *elems;
+	unsigned int elem_size, num_elems;
+};
+
+/**
+ * drm_dynarray_elem - Return a pointer to an element
+ * @dynarr: the dynamic array
+ * @index: the index of the element
+ *
+ * Returns:
+ * A pointer to the element at @index in the array.
+ */
+static inline void *drm_dynarray_elem(const struct drm_dynarray *dynarr,
+				      unsigned int index)
+{
+	if (index >= dynarr->num_elems)
+		return NULL;
+	return dynarr->elems + index * dynarr->elem_size;
+}
+
+int drm_dynarray_reserve(struct drm_dynarray *dynarr,
+			 unsigned int index);
+
+void drm_dynarray_init(struct drm_dynarray *dynarr,
+		       unsigned int elem_size);
+void drm_dynarray_fini(struct drm_dynarray *dynarr);
+
+#endif
-- 
2.13.0

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