Revert "dma-buf: heaps: Add system heap to dmabuf heaps"

This reverts commit 47a32f9c.

This patchset doesn't meet the UAPI requirements set out in [1] for the DRM
subsystem. Once the userspace component is reviewed and ready for merge
we can try again.

[1]- https://01.org/linuxgraphics/gfx-docs/drm/gpu/drm-uapi.html#open-source-userspace-requirements

Fixes: 47a32f9c ("dma-buf: heaps: Add system heap to dmabuf heaps")
Cc: Laura Abbott <labbott@redhat.com>
Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Liam Mark <lmark@codeaurora.org>
Cc: Pratik Patel <pratikp@codeaurora.org>
Cc: Brian Starkey <Brian.Starkey@arm.com>
Cc: Vincent Donnefort <Vincent.Donnefort@arm.com>
Cc: Sudipto Paul <Sudipto.Paul@arm.com>
Cc: Andrew F. Davis <afd@ti.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chenbo Feng <fengc@google.com>
Cc: Alistair Strachan <astrachan@google.com>
Cc: Hridya Valsaraju <hridya@google.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: dri-devel@lists.freedesktop.org
Cc: Brian Starkey <brian.starkey@arm.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: "Andrew F. Davis" <afd@ti.com>
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Acked-by: David Airlie <airlied@linux.ie>
Signed-off-by: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20191030203003.101156-4-sean@poorly.run

drivers/dma-buf/Kconfig

@@ -53,6 +53,4 @@ menuconfig DMABUF_HEAPS
 	  allows userspace to allocate dma-bufs that can be shared
 	  between drivers.
 
-source "drivers/dma-buf/heaps/Kconfig"
-
 endmenu

drivers/dma-buf/heaps/Kconfig

-config DMABUF_HEAPS_SYSTEM
-	bool "DMA-BUF System Heap"
-	depends on DMABUF_HEAPS
-	help
-	  Choose this option to enable the system dmabuf heap. The system heap
-	  is backed by pages from the buddy allocator. If in doubt, say Y.

drivers/dma-buf/heaps/Makefile

 # SPDX-License-Identifier: GPL-2.0
 obj-y					+= heap-helpers.o
-obj-$(CONFIG_DMABUF_HEAPS_SYSTEM)	+= system_heap.o

drivers/dma-buf/heaps/system_heap.c

-// SPDX-License-Identifier: GPL-2.0
-/*
- * DMABUF System heap exporter
- *
- * Copyright (C) 2011 Google, Inc.
- * Copyright (C) 2019 Linaro Ltd.
- */
-
-#include <linux/dma-buf.h>
-#include <linux/dma-mapping.h>
-#include <linux/dma-heap.h>
-#include <linux/err.h>
-#include <linux/highmem.h>
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/scatterlist.h>
-#include <linux/slab.h>
-#include <linux/sched/signal.h>
-#include <asm/page.h>
-
-#include "heap-helpers.h"
-
-struct dma_heap *sys_heap;
-
-static void system_heap_free(struct heap_helper_buffer *buffer)
-{
-	pgoff_t pg;
-
-	for (pg = 0; pg < buffer->pagecount; pg++)
-		__free_page(buffer->pages[pg]);
-	kfree(buffer->pages);
-	kfree(buffer);
-}
-
-static int system_heap_allocate(struct dma_heap *heap,
-				unsigned long len,
-				unsigned long fd_flags,
-				unsigned long heap_flags)
-{
-	struct heap_helper_buffer *helper_buffer;
-	struct dma_buf *dmabuf;
-	int ret = -ENOMEM;
-	pgoff_t pg;
-
-	helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
-	if (!helper_buffer)
-		return -ENOMEM;
-
-	init_heap_helper_buffer(helper_buffer, system_heap_free);
-	helper_buffer->flags = heap_flags;
-	helper_buffer->heap = heap;
-	helper_buffer->size = len;
-
-	helper_buffer->pagecount = len / PAGE_SIZE;
-	helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
-					     sizeof(*helper_buffer->pages),
-					     GFP_KERNEL);
-	if (!helper_buffer->pages) {
-		ret = -ENOMEM;
-		goto err0;
-	}
-
-	for (pg = 0; pg < helper_buffer->pagecount; pg++) {
-		/*
-		 * Avoid trying to allocate memory if the process
-		 * has been killed by by SIGKILL
-		 */
-		if (fatal_signal_pending(current))
-			goto err1;
-
-		helper_buffer->pages[pg] = alloc_page(GFP_KERNEL | __GFP_ZERO);
-		if (!helper_buffer->pages[pg])
-			goto err1;
-	}
-
-	/* create the dmabuf */
-	dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
-	if (IS_ERR(dmabuf)) {
-		ret = PTR_ERR(dmabuf);
-		goto err1;
-	}
-
-	helper_buffer->dmabuf = dmabuf;
-
-	ret = dma_buf_fd(dmabuf, fd_flags);
-	if (ret < 0) {
-		dma_buf_put(dmabuf);
-		/* just return, as put will call release and that will free */
-		return ret;
-	}
-
-	return ret;
-
-err1:
-	while (pg > 0)
-		__free_page(helper_buffer->pages[--pg]);
-	kfree(helper_buffer->pages);
-err0:
-	kfree(helper_buffer);
-
-	return -ENOMEM;
-}
-
-static const struct dma_heap_ops system_heap_ops = {
-	.allocate = system_heap_allocate,
-};
-
-static int system_heap_create(void)
-{
-	struct dma_heap_export_info exp_info;
-	int ret = 0;
-
-	exp_info.name = "system_heap";
-	exp_info.ops = &system_heap_ops;
-	exp_info.priv = NULL;
-
-	sys_heap = dma_heap_add(&exp_info);
-	if (IS_ERR(sys_heap))
-		ret = PTR_ERR(sys_heap);
-
-	return ret;
-}
-module_init(system_heap_create);
-MODULE_LICENSE("GPL v2");