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

This reverts commit 43d7238f.

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: 43d7238f ("dma-buf: heaps: Add CMA 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/20191030203003.101156-3-sean@poorly.run

drivers/dma-buf/heaps/Kconfig

@@ -4,11 +4,3 @@ config DMABUF_HEAPS_SYSTEM
 	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.
-
-config DMABUF_HEAPS_CMA
-	bool "DMA-BUF CMA Heap"
-	depends on DMABUF_HEAPS && DMA_CMA
-	help
-	  Choose this option to enable dma-buf CMA heap. This heap is backed
-	  by the Contiguous Memory Allocator (CMA). If your system has these
-	  regions, you should say Y here.

drivers/dma-buf/heaps/Makefile

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

drivers/dma-buf/heaps/cma_heap.c

-// SPDX-License-Identifier: GPL-2.0
-/*
- * DMABUF CMA heap exporter
- *
- * Copyright (C) 2012, 2019 Linaro Ltd.
- * Author: <benjamin.gaignard@linaro.org> for ST-Ericsson.
- */
-
-#include <linux/cma.h>
-#include <linux/device.h>
-#include <linux/dma-buf.h>
-#include <linux/dma-heap.h>
-#include <linux/dma-contiguous.h>
-#include <linux/err.h>
-#include <linux/errno.h>
-#include <linux/highmem.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/scatterlist.h>
-#include <linux/sched/signal.h>
-
-#include "heap-helpers.h"
-
-struct cma_heap {
-	struct dma_heap *heap;
-	struct cma *cma;
-};
-
-static void cma_heap_free(struct heap_helper_buffer *buffer)
-{
-	struct cma_heap *cma_heap = dma_heap_get_drvdata(buffer->heap);
-	unsigned long nr_pages = buffer->pagecount;
-	struct page *cma_pages = buffer->priv_virt;
-
-	/* free page list */
-	kfree(buffer->pages);
-	/* release memory */
-	cma_release(cma_heap->cma, cma_pages, nr_pages);
-	kfree(buffer);
-}
-
-/* dmabuf heap CMA operations functions */
-static int cma_heap_allocate(struct dma_heap *heap,
-			     unsigned long len,
-			     unsigned long fd_flags,
-			     unsigned long heap_flags)
-{
-	struct cma_heap *cma_heap = dma_heap_get_drvdata(heap);
-	struct heap_helper_buffer *helper_buffer;
-	struct page *cma_pages;
-	size_t size = PAGE_ALIGN(len);
-	unsigned long nr_pages = size >> PAGE_SHIFT;
-	unsigned long align = get_order(size);
-	struct dma_buf *dmabuf;
-	int ret = -ENOMEM;
-	pgoff_t pg;
-
-	if (align > CONFIG_CMA_ALIGNMENT)
-		align = CONFIG_CMA_ALIGNMENT;
-
-	helper_buffer = kzalloc(sizeof(*helper_buffer), GFP_KERNEL);
-	if (!helper_buffer)
-		return -ENOMEM;
-
-	init_heap_helper_buffer(helper_buffer, cma_heap_free);
-	helper_buffer->flags = heap_flags;
-	helper_buffer->heap = heap;
-	helper_buffer->size = len;
-
-	cma_pages = cma_alloc(cma_heap->cma, nr_pages, align, false);
-	if (!cma_pages)
-		goto free_buf;
-
-	if (PageHighMem(cma_pages)) {
-		unsigned long nr_clear_pages = nr_pages;
-		struct page *page = cma_pages;
-
-		while (nr_clear_pages > 0) {
-			void *vaddr = kmap_atomic(page);
-
-			memset(vaddr, 0, PAGE_SIZE);
-			kunmap_atomic(vaddr);
-			/*
-			 * Avoid wasting time zeroing memory if the process
-			 * has been killed by by SIGKILL
-			 */
-			if (fatal_signal_pending(current))
-				goto free_cma;
-
-			page++;
-			nr_clear_pages--;
-		}
-	} else {
-		memset(page_address(cma_pages), 0, size);
-	}
-
-	helper_buffer->pagecount = nr_pages;
-	helper_buffer->pages = kmalloc_array(helper_buffer->pagecount,
-					     sizeof(*helper_buffer->pages),
-					     GFP_KERNEL);
-	if (!helper_buffer->pages) {
-		ret = -ENOMEM;
-		goto free_cma;
-	}
-
-	for (pg = 0; pg < helper_buffer->pagecount; pg++)
-		helper_buffer->pages[pg] = &cma_pages[pg];
-
-	/* create the dmabuf */
-	dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
-	if (IS_ERR(dmabuf)) {
-		ret = PTR_ERR(dmabuf);
-		goto free_pages;
-	}
-
-	helper_buffer->dmabuf = dmabuf;
-	helper_buffer->priv_virt = cma_pages;
-
-	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;
-
-free_pages:
-	kfree(helper_buffer->pages);
-free_cma:
-	cma_release(cma_heap->cma, cma_pages, nr_pages);
-free_buf:
-	kfree(helper_buffer);
-	return ret;
-}
-
-static const struct dma_heap_ops cma_heap_ops = {
-	.allocate = cma_heap_allocate,
-};
-
-static int __add_cma_heap(struct cma *cma, void *data)
-{
-	struct cma_heap *cma_heap;
-	struct dma_heap_export_info exp_info;
-
-	cma_heap = kzalloc(sizeof(*cma_heap), GFP_KERNEL);
-	if (!cma_heap)
-		return -ENOMEM;
-	cma_heap->cma = cma;
-
-	exp_info.name = cma_get_name(cma);
-	exp_info.ops = &cma_heap_ops;
-	exp_info.priv = cma_heap;
-
-	cma_heap->heap = dma_heap_add(&exp_info);
-	if (IS_ERR(cma_heap->heap)) {
-		int ret = PTR_ERR(cma_heap->heap);
-
-		kfree(cma_heap);
-		return ret;
-	}
-
-	return 0;
-}
-
-static int add_default_cma_heap(void)
-{
-	struct cma *default_cma = dev_get_cma_area(NULL);
-	int ret = 0;
-
-	if (default_cma)
-		ret = __add_cma_heap(default_cma, NULL);
-
-	return ret;
-}
-module_init(add_default_cma_heap);
-MODULE_DESCRIPTION("DMA-BUF CMA Heap");
-MODULE_LICENSE("GPL v2");