gpu: nvgpu: Move kmem_caches to allocator

Instead of using a single static kmem_cache for each type of
data structure the allocators may want to allocate each
allocator now has its own instance of the kmem_cache. This is
done so that each GPU driver instance can accurately track how
much memory it is using.

In order to support this on older kernels a new NVGPU API has
been made,

  nvgpu_kmem_cache_create(struct gk20a *g, size_t size)

To handle the possibility that caches cannot be created with
the same name.

This patch also fixes numerous places where kfree() was wrongly
used to free kmem_cache allocs.

Bug 1799159
Bug 1823380

Change-Id: Id674f9a5445fde3f95db65ad6bf3ea990444603d
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/1283826
Reviewed-by: svccoveritychecker <svccoveritychecker@nvidia.com>
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
GVS: Gerrit_Virtual_Submit

drivers/gpu/nvgpu/common/linux/kmem.c

@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2017, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/atomic.h>
+
+#include <nvgpu/kmem.h>
+
+/*
+ * Statically declared because this needs to be shared across all nvgpu driver
+ * instances. This makes sure that all kmem caches are _definitely_ uniquely
+ * named.
+ */
+static atomic_t kmem_cache_id;
+
+/*
+ * Linux specific version of the nvgpu_kmem_cache struct. This type is
+ * completely opaque to the rest of the driver.
+ */
+struct nvgpu_kmem_cache {
+	struct gk20a *g;
+	struct kmem_cache *cache;
+
+	/*
+	 * Memory to hold the kmem_cache unique name. Only necessary on our
+	 * k3.10 kernel when not using the SLUB allocator but it's easier to
+	 * just carry this on to newer kernels.
+	 */
+	char name[128];
+};
+
+struct nvgpu_kmem_cache *nvgpu_kmem_cache_create(struct gk20a *g, size_t size)
+{
+	struct nvgpu_kmem_cache *cache =
+		kzalloc(sizeof(struct nvgpu_kmem_cache), GFP_KERNEL);
+
+	if (!cache)
+		return NULL;
+
+	cache->g = g;
+
+	snprintf(cache->name, sizeof(cache->name),
+		 "nvgpu-cache-0x%p-%d-%d", g, (int)size,
+		 atomic_inc_return(&kmem_cache_id));
+	cache->cache = kmem_cache_create(cache->name,
+					 size, size, 0, NULL);
+	if (!cache->cache) {
+		kfree(cache);
+		return NULL;
+	}
+
+	return cache;
+}
+
+void nvgpu_kmem_cache_destroy(struct nvgpu_kmem_cache *cache)
+{
+	kmem_cache_destroy(cache->cache);
+	kfree(cache);
+}
+
+void *nvgpu_kmem_cache_alloc(struct nvgpu_kmem_cache *cache)
+{
+	return kmem_cache_alloc(cache->cache, GFP_KERNEL);
+}
+
+void nvgpu_kmem_cache_free(struct nvgpu_kmem_cache *cache, void *ptr)
+{
+	kmem_cache_free(cache->cache, ptr);
+}