On 3/28/19 7:15 PM, John Stultz wrote:

Add generic helper dmabuf ops for dma heaps, so we can reduce the amount of duplicative code for the exported dmabufs.

This code is an evolution of the Android ION implementation, so thanks to its original authors and maintainters: Rebecca Schultz Zavin, Colin Cross, Laura Abbott, and others!

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: Xu YiPing xuyiping@hisilicon.com Cc: "Chenfeng (puck)" puck.chen@hisilicon.com Cc: butao butao@hisilicon.com Cc: "Xiaqing (A)" saberlily.xia@hisilicon.com Cc: Yudongbin yudongbin@hisilicon.com Cc: Christoph Hellwig hch@infradead.org Cc: Chenbo Feng fengc@google.com Cc: Alistair Strachan astrachan@google.com Cc: dri-devel@lists.freedesktop.org Signed-off-by: John Stultz john.stultz@linaro.org

---

v2:

• Removed cache management performance hack that I had accidentally folded in.
• Removed stats code that was in helpers
• Lots of checkpatch cleanups

v3:

• Uninline INIT_HEAP_HELPER_BUFFER (suggested by Christoph)
• Switch to WARN on buffer destroy failure (suggested by Brian)
• buffer->kmap_cnt decrementing cleanup (suggested by Christoph)
• Extra buffer->vaddr checking in dma_heap_dma_buf_kmap (suggested by Brian)
• Switch to_helper_buffer from macro to inline function (suggested by Benjamin)
• Rename kmap->vmap (folded in from Andrew)
• Use vmap for vmapping - not begin_cpu_access (folded in from Andrew)
• Drop kmap for now, as its optional (folded in from Andrew)
• Fold dma_heap_map_user into the single caller (foled in from Andrew)
• Folded in patch from Andrew to track page list per heap not sglist, which simplifies the tracking logic

---

drivers/dma-buf/Makefile | 1 + drivers/dma-buf/heaps/Makefile | 2 + drivers/dma-buf/heaps/heap-helpers.c | 261 +++++++++++++++++++++++++++++++++++ drivers/dma-buf/heaps/heap-helpers.h | 55 ++++++++ include/linux/dma-heap.h | 14 +- 5 files changed, 320 insertions(+), 13 deletions(-) create mode 100644 drivers/dma-buf/heaps/Makefile create mode 100644 drivers/dma-buf/heaps/heap-helpers.c create mode 100644 drivers/dma-buf/heaps/heap-helpers.h

diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile index b0332f1..09c2f2d 100644 --- a/drivers/dma-buf/Makefile +++ b/drivers/dma-buf/Makefile @@ -1,4 +1,5 @@ obj-y := dma-buf.o dma-fence.o dma-fence-array.o reservation.o seqno-fence.o +obj-$(CONFIG_DMABUF_HEAPS) += heaps/ obj-$(CONFIG_DMABUF_HEAPS) += dma-heap.o obj-$(CONFIG_SYNC_FILE) += sync_file.o obj-$(CONFIG_SW_SYNC) += sw_sync.o sync_debug.o diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile new file mode 100644 index 0000000..de49898 --- /dev/null +++ b/drivers/dma-buf/heaps/Makefile @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0 +obj-y += heap-helpers.o diff --git a/drivers/dma-buf/heaps/heap-helpers.c b/drivers/dma-buf/heaps/heap-helpers.c new file mode 100644 index 0000000..00cbdbb --- /dev/null +++ b/drivers/dma-buf/heaps/heap-helpers.c @@ -0,0 +1,261 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/device.h> +#include <linux/dma-buf.h> +#include <linux/err.h> +#include <linux/idr.h> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <uapi/linux/dma-heap.h>

+#include "heap-helpers.h"

+void INIT_HEAP_HELPER_BUFFER(struct heap_helper_buffer *buffer,

• 	     void (*free)(struct heap_helper_buffer *))
  

+{

• buffer->private_flags = 0;
• buffer->priv_virt = NULL;
• mutex_init(&buffer->lock);
• buffer->vmap_cnt = 0;
• buffer->vaddr = NULL;
• INIT_LIST_HEAD(&buffer->attachments);
• buffer->free = free;

+}

+static void *dma_heap_map_kernel(struct heap_helper_buffer *buffer) +{

• void *vaddr;
• vaddr = vmap(buffer->pages, buffer->pagecount, VM_MAP, PAGE_KERNEL);
• if (!vaddr)

• return ERR_PTR(-ENOMEM);
  

• return vaddr;

+}

+void dma_heap_buffer_destroy(struct dma_heap_buffer *heap_buffer) +{

• struct heap_helper_buffer *buffer = to_helper_buffer(heap_buffer);
• if (buffer->vmap_cnt > 0) {

• WARN("%s: buffer still mapped in the kernel\n",
  

• 	     __func__);
  

• vunmap(buffer->vaddr);
  

• }
• buffer->free(buffer);

+}

+static void *dma_heap_buffer_vmap_get(struct dma_heap_buffer *heap_buffer) +{

• struct heap_helper_buffer *buffer = to_helper_buffer(heap_buffer);
• void *vaddr;
• if (buffer->vmap_cnt) {

• buffer->vmap_cnt++;
  

• return buffer->vaddr;
  

• }
• vaddr = dma_heap_map_kernel(buffer);
• if (WARN_ONCE(!vaddr,

•       "heap->ops->map_kernel should return ERR_PTR on error"))
  

• return ERR_PTR(-EINVAL);
  

• if (IS_ERR(vaddr))

• return vaddr;
  

• buffer->vaddr = vaddr;
• buffer->vmap_cnt++;
• return vaddr;

+}

+static void dma_heap_buffer_vmap_put(struct dma_heap_buffer *heap_buffer) +{

• struct heap_helper_buffer *buffer = to_helper_buffer(heap_buffer);
• if (!--buffer->vmap_cnt) {

• vunmap(buffer->vaddr);
  

• buffer->vaddr = NULL;
  

• }

+}

+struct dma_heaps_attachment {

• struct device *dev;
• struct sg_table table;
• struct list_head list;

+};

+static int dma_heap_attach(struct dma_buf *dmabuf,

• 	      struct dma_buf_attachment *attachment)
  

+{

• struct dma_heaps_attachment *a;
• struct dma_heap_buffer *heap_buffer = dmabuf->priv;
• struct heap_helper_buffer *buffer = to_helper_buffer(heap_buffer);
• int ret;
• a = kzalloc(sizeof(*a), GFP_KERNEL);
• if (!a)

• return -ENOMEM;
  

• ret = sg_alloc_table_from_pages(&a->table, buffer->pages,

• 			buffer->pagecount, 0,
  

• 			buffer->pagecount << PAGE_SHIFT,
  

• 			GFP_KERNEL);
  

• if (ret) {

• kfree(a);
  

• return ret;
  

• }
• a->dev = attachment->dev;
• INIT_LIST_HEAD(&a->list);
• attachment->priv = a;
• mutex_lock(&buffer->lock);
• list_add(&a->list, &buffer->attachments);
• mutex_unlock(&buffer->lock);
• return 0;

+}

+static void dma_heap_detatch(struct dma_buf *dmabuf,

• 		struct dma_buf_attachment *attachment)
  

+{

• struct dma_heaps_attachment *a = attachment->priv;
• struct dma_heap_buffer *heap_buffer = dmabuf->priv;
• struct heap_helper_buffer *buffer = to_helper_buffer(heap_buffer);
• mutex_lock(&buffer->lock);
• list_del(&a->list);
• mutex_unlock(&buffer->lock);
• sg_free_table(&a->table);
• kfree(a);

+}

+static struct sg_table *dma_heap_map_dma_buf(

• 			struct dma_buf_attachment *attachment,
  

• 			enum dma_data_direction direction)
  

+{

• struct dma_heaps_attachment *a = attachment->priv;
• struct sg_table *table;
• table = &a->table;
• if (!dma_map_sg(attachment->dev, table->sgl, table->nents,

• 	direction))
  

• table = ERR_PTR(-ENOMEM);
  

• return table;

+}

+static void dma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment,

• 	      struct sg_table *table,
  

• 	      enum dma_data_direction direction)
  

+{

• dma_unmap_sg(attachment->dev, table->sgl, table->nents, direction);

+}

+static vm_fault_t dma_heap_vm_fault(struct vm_fault *vmf) +{

• struct vm_area_struct *vma = vmf->vma;
• struct heap_helper_buffer *buffer = vma->vm_private_data;
• vmf->page = buffer->pages[vmf->pgoff];
• get_page(vmf->page);
• return 0;

+}

+static const struct vm_operations_struct dma_heap_vm_ops = {

• .fault = dma_heap_vm_fault,

+};

+static int dma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) +{

• struct dma_heap_buffer *heap_buffer = dmabuf->priv;
• struct heap_helper_buffer *buffer = to_helper_buffer(heap_buffer);
• if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)

• return -EINVAL;
  

• vma->vm_ops = &dma_heap_vm_ops;
• vma->vm_private_data = buffer;
• return 0;

+}

+static void dma_heap_dma_buf_release(struct dma_buf *dmabuf) +{

• struct dma_heap_buffer *buffer = dmabuf->priv;
• dma_heap_buffer_destroy(buffer);

+}

+static int dma_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,

• 			enum dma_data_direction direction)
  

+{

• struct dma_heap_buffer *heap_buffer = dmabuf->priv;
• struct heap_helper_buffer *buffer = to_helper_buffer(heap_buffer);
• struct dma_heaps_attachment *a;
• int ret = 0;
• mutex_lock(&buffer->lock);
• list_for_each_entry(a, &buffer->attachments, list) {

• dma_sync_sg_for_cpu(a->dev, a->table.sgl, a->table.nents,
  

• 		    direction);
  

• }
• mutex_unlock(&buffer->lock);
• return ret;

+}

+static int dma_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf,

• 		      enum dma_data_direction direction)
  

+{

• struct dma_heap_buffer *heap_buffer = dmabuf->priv;
• struct heap_helper_buffer *buffer = to_helper_buffer(heap_buffer);
• struct dma_heaps_attachment *a;
• mutex_lock(&buffer->lock);
• list_for_each_entry(a, &buffer->attachments, list) {

• dma_sync_sg_for_device(a->dev, a->table.sgl, a->table.nents,
  

• 		       direction);
  

• }
• mutex_unlock(&buffer->lock);
• return 0;

+}

+void *dma_heap_dma_buf_vmap(struct dma_buf *dmabuf) +{

• struct dma_heap_buffer *heap_buffer = dmabuf->priv;
• struct heap_helper_buffer *buffer = to_helper_buffer(heap_buffer);
• void *vaddr;
• mutex_lock(&buffer->lock);
• vaddr = dma_heap_buffer_vmap_get(heap_buffer);
• mutex_unlock(&buffer->lock);
• return vaddr;

+}

+void dma_heap_dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr) +{

• struct dma_heap_buffer *heap_buffer = dmabuf->priv;
• struct heap_helper_buffer *buffer = to_helper_buffer(heap_buffer);
• mutex_lock(&buffer->lock);
• dma_heap_buffer_vmap_put(heap_buffer);
• mutex_unlock(&buffer->lock);

+}

+const struct dma_buf_ops heap_helper_ops = {

• .map_dma_buf = dma_heap_map_dma_buf,
• .unmap_dma_buf = dma_heap_unmap_dma_buf,
• .mmap = dma_heap_mmap,
• .release = dma_heap_dma_buf_release,
• .attach = dma_heap_attach,
• .detach = dma_heap_detatch,
• .begin_cpu_access = dma_heap_dma_buf_begin_cpu_access,
• .end_cpu_access = dma_heap_dma_buf_end_cpu_access,
• .vmap = dma_heap_dma_buf_vmap,
• .vunmap = dma_heap_dma_buf_vunmap,

+}; diff --git a/drivers/dma-buf/heaps/heap-helpers.h b/drivers/dma-buf/heaps/heap-helpers.h new file mode 100644 index 0000000..a17502d --- /dev/null +++ b/drivers/dma-buf/heaps/heap-helpers.h @@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/*

• • DMABUF Heaps helper code
• • Copyright (C) 2011 Google, Inc.
• • Copyright (C) 2019 Linaro Ltd.
• */

+#ifndef _HEAP_HELPERS_H +#define _HEAP_HELPERS_H

+#include <linux/dma-heap.h> +#include <linux/list.h>

+/**

• • struct dma_heap_buffer - metadata for a particular buffer
• • @heap: back pointer to the heap the buffer came from
• • @dmabuf: backing dma-buf for this buffer
• • @size: size of the buffer
• • @flags: buffer specific flags
• */

+struct dma_heap_buffer {

• struct dma_heap *heap;
• struct dma_buf *dmabuf;
• size_t size;
• unsigned long flags;

+};

+struct heap_helper_buffer {

• struct dma_heap_buffer heap_buffer;
• unsigned long private_flags;
• void *priv_virt;
• struct mutex lock;
• int vmap_cnt;
• void *vaddr;
• pgoff_t pagecount;
• struct page **pages;
• struct list_head attachments;
• void (*free)(struct heap_helper_buffer *buffer);

+};

+static inline struct heap_helper_buffer *to_helper_buffer(

• 				struct dma_heap_buffer *h)
  

+{

• return container_of(h, struct heap_helper_buffer, heap_buffer);

+}

+void INIT_HEAP_HELPER_BUFFER(struct heap_helper_buffer *buffer,

• 		 void (*free)(struct heap_helper_buffer *));
  

+extern const struct dma_buf_ops heap_helper_ops;

+#endif /* _HEAP_HELPERS_H */ diff --git a/include/linux/dma-heap.h b/include/linux/dma-heap.h index d7bf624..d17b839 100644 --- a/include/linux/dma-heap.h +++ b/include/linux/dma-heap.h @@ -12,19 +12,7 @@ #include <linux/cdev.h> #include <linux/types.h>

-/**

• • struct dma_heap_buffer - metadata for a particular buffer
• • @heap: back pointer to the heap the buffer came from
• • @dmabuf: backing dma-buf for this buffer
• • @size: size of the buffer
• • @flags: buffer specific flags
• */

-struct dma_heap_buffer {

• struct dma_heap *heap;
• struct dma_buf *dmabuf;
• size_t size;
• unsigned long flags;

-}; +struct dma_heap;

This change can get squashed into the first patch.

Andrew

/**

• struct dma_heap_ops - ops to operate on a given heap

On 3/29/19 9:44 AM, Benjamin Gaignard wrote:

Le ven. 29 mars 2019 à 01:16, John Stultz john.stultz@linaro.org a écrit :

...

This adds a CMA heap, which allows userspace to allocate a dma-buf of contiguous memory out of a CMA region.

This code is an evolution of the Android ION implementation, so thanks to its original author and maintainters: Benjamin Gaignard, Laura Abbott, and others!

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: Xu YiPing xuyiping@hisilicon.com Cc: "Chenfeng (puck)" puck.chen@hisilicon.com Cc: butao butao@hisilicon.com Cc: "Xiaqing (A)" saberlily.xia@hisilicon.com Cc: Yudongbin yudongbin@hisilicon.com Cc: Christoph Hellwig hch@infradead.org Cc: Chenbo Feng fengc@google.com Cc: Alistair Strachan astrachan@google.com Cc: dri-devel@lists.freedesktop.org Signed-off-by: John Stultz john.stultz@linaro.org

---

v2:

• Switch allocate to return dmabuf fd
• Simplify init code
• Checkpatch fixups

v3:

• Switch to inline function for to_cma_heap()
• Minor cleanups suggested by Brian
• Fold in new registration style from Andrew
• Folded in changes from Andrew to use simplified page list from the heap helpers

---

drivers/dma-buf/heaps/Kconfig | 8 ++ drivers/dma-buf/heaps/Makefile | 1 + drivers/dma-buf/heaps/cma_heap.c | 170 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 179 insertions(+) create mode 100644 drivers/dma-buf/heaps/cma_heap.c

diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig index 2050527..a5eef06 100644 --- a/drivers/dma-buf/heaps/Kconfig +++ b/drivers/dma-buf/heaps/Kconfig @@ -4,3 +4,11 @@ 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.
  

diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile index d1808ec..6e54cde 100644 --- a/drivers/dma-buf/heaps/Makefile +++ b/drivers/dma-buf/heaps/Makefile @@ -1,3 +1,4 @@ # 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 diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c new file mode 100644 index 0000000..f4485c60 --- /dev/null +++ b/drivers/dma-buf/heaps/cma_heap.c @@ -0,0 +1,170 @@ +// 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/device.h> +#include <linux/dma-buf.h> +#include <linux/dma-heap.h> +#include <linux/slab.h> +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/cma.h> +#include <linux/scatterlist.h> +#include <linux/highmem.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_data(buffer->heap_buffer.heap);
  

•   struct page *pages = buffer->priv_virt;
  

•   unsigned long nr_pages;
  

•   nr_pages = buffer->heap_buffer.size >> PAGE_SHIFT;
  

•   /* free page list */
  

•   kfree(buffer->pages);
  

•   /* release memory */
  

•   cma_release(cma_heap->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 flags)
  

+{

•   struct cma_heap *cma_heap = dma_heap_get_data(heap);
  

•   struct heap_helper_buffer *helper_buffer;
  

•   struct page *pages;
  

•   size_t size = PAGE_ALIGN(len);
  

•   unsigned long nr_pages = size >> PAGE_SHIFT;
  

•   unsigned long align = get_order(size);
  

•   DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
  

•   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->heap_buffer.flags = flags;
  

•   helper_buffer->heap_buffer.heap = heap;
  

•   helper_buffer->heap_buffer.size = len;
  

•   pages = cma_alloc(cma_heap->cma, nr_pages, align, false);
  

•   if (!pages)
  

•           goto free_buf;
  

•   if (PageHighMem(pages)) {
  

•           unsigned long nr_clear_pages = nr_pages;
  

•           struct page *page = pages;
  

•           while (nr_clear_pages > 0) {
  

•                   void *vaddr = kmap_atomic(page);
  

•                   memset(vaddr, 0, PAGE_SIZE);
  

•                   kunmap_atomic(vaddr);
  

•                   page++;
  

•                   nr_clear_pages--;
  

•           }
  

•   } else {
  

•           memset(page_address(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] = &pages[pg];
  

•           if (!helper_buffer->pages[pg])
  

•                   goto free_pages;
  

•   }
  

•   /* create the dmabuf */
  

•   exp_info.ops = &heap_helper_ops;
  

•   exp_info.size = len;
  

•   exp_info.flags = O_RDWR;
  

I think that the flags should be provided when requesting the allocation like it is done in DRM or V4L2. For me DMA_HEAP_VALID_FLAGS = (O_CLOEXEC | O_ACCMODE).

So something like done in udmabuf?

https://elixir.bootlin.com/linux/v5.1-rc1/source/include/uapi/linux/udmabuf....

I think that can be arranged.

John,

This might be a good reason to move the dma_buf_fd() call below out of the heap and back into the core. That way the file exporting flags can be common and core handled. I don't think it would complicate the error handling any as we only need to dma_buf_put(dmabuf) in the core on failure and the heap specific cleanup will happen for us.

Andrew

Benjamin

Benjamin

...

•   exp_info.priv = &helper_buffer->heap_buffer;
  

•   dmabuf = dma_buf_export(&exp_info);
  

•   if (IS_ERR(dmabuf)) {
  

•           ret = PTR_ERR(dmabuf);
  

•           goto free_pages;
  

•   }
  

•   helper_buffer->heap_buffer.dmabuf = dmabuf;
  

•   helper_buffer->priv_virt = pages;
  

•   ret = dma_buf_fd(dmabuf, O_CLOEXEC);
  

•   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, pages, nr_pages);
  

+free_buf:

•   kfree(helper_buffer);
  

•   return ret;
  

+}

+static 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_cma_heaps(void) +{

•   cma_for_each_area(__add_cma_heap, NULL);
  

•   return 0;
  

+}

+device_initcall(add_cma_heaps);

2.7.4

On 3/29/19 10:30 AM, Benjamin Gaignard wrote:

Le ven. 29 mars 2019 à 16:19, Andrew F. Davis afd@ti.com a écrit :

...

On 3/29/19 9:44 AM, Benjamin Gaignard wrote:

...

Le ven. 29 mars 2019 à 01:16, John Stultz john.stultz@linaro.org a écrit :

...

This adds a CMA heap, which allows userspace to allocate a dma-buf of contiguous memory out of a CMA region.

This code is an evolution of the Android ION implementation, so thanks to its original author and maintainters: Benjamin Gaignard, Laura Abbott, and others!

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: Xu YiPing xuyiping@hisilicon.com Cc: "Chenfeng (puck)" puck.chen@hisilicon.com Cc: butao butao@hisilicon.com Cc: "Xiaqing (A)" saberlily.xia@hisilicon.com Cc: Yudongbin yudongbin@hisilicon.com Cc: Christoph Hellwig hch@infradead.org Cc: Chenbo Feng fengc@google.com Cc: Alistair Strachan astrachan@google.com Cc: dri-devel@lists.freedesktop.org Signed-off-by: John Stultz john.stultz@linaro.org

---

v2:

• Switch allocate to return dmabuf fd
• Simplify init code
• Checkpatch fixups

v3:

• Switch to inline function for to_cma_heap()
• Minor cleanups suggested by Brian
• Fold in new registration style from Andrew
• Folded in changes from Andrew to use simplified page list from the heap helpers

---

drivers/dma-buf/heaps/Kconfig | 8 ++ drivers/dma-buf/heaps/Makefile | 1 + drivers/dma-buf/heaps/cma_heap.c | 170 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 179 insertions(+) create mode 100644 drivers/dma-buf/heaps/cma_heap.c

diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig index 2050527..a5eef06 100644 --- a/drivers/dma-buf/heaps/Kconfig +++ b/drivers/dma-buf/heaps/Kconfig @@ -4,3 +4,11 @@ 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.
  

diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile index d1808ec..6e54cde 100644 --- a/drivers/dma-buf/heaps/Makefile +++ b/drivers/dma-buf/heaps/Makefile @@ -1,3 +1,4 @@ # 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 diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c new file mode 100644 index 0000000..f4485c60 --- /dev/null +++ b/drivers/dma-buf/heaps/cma_heap.c @@ -0,0 +1,170 @@ +// 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/device.h> +#include <linux/dma-buf.h> +#include <linux/dma-heap.h> +#include <linux/slab.h> +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/cma.h> +#include <linux/scatterlist.h> +#include <linux/highmem.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_data(buffer->heap_buffer.heap);
  

•   struct page *pages = buffer->priv_virt;
  

•   unsigned long nr_pages;
  

•   nr_pages = buffer->heap_buffer.size >> PAGE_SHIFT;
  

•   /* free page list */
  

•   kfree(buffer->pages);
  

•   /* release memory */
  

•   cma_release(cma_heap->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 flags)
  

+{

•   struct cma_heap *cma_heap = dma_heap_get_data(heap);
  

•   struct heap_helper_buffer *helper_buffer;
  

•   struct page *pages;
  

•   size_t size = PAGE_ALIGN(len);
  

•   unsigned long nr_pages = size >> PAGE_SHIFT;
  

•   unsigned long align = get_order(size);
  

•   DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
  

•   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->heap_buffer.flags = flags;
  

•   helper_buffer->heap_buffer.heap = heap;
  

•   helper_buffer->heap_buffer.size = len;
  

•   pages = cma_alloc(cma_heap->cma, nr_pages, align, false);
  

•   if (!pages)
  

•           goto free_buf;
  

•   if (PageHighMem(pages)) {
  

•           unsigned long nr_clear_pages = nr_pages;
  

•           struct page *page = pages;
  

•           while (nr_clear_pages > 0) {
  

•                   void *vaddr = kmap_atomic(page);
  

•                   memset(vaddr, 0, PAGE_SIZE);
  

•                   kunmap_atomic(vaddr);
  

•                   page++;
  

•                   nr_clear_pages--;
  

•           }
  

•   } else {
  

•           memset(page_address(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] = &pages[pg];
  

•           if (!helper_buffer->pages[pg])
  

•                   goto free_pages;
  

•   }
  

•   /* create the dmabuf */
  

•   exp_info.ops = &heap_helper_ops;
  

•   exp_info.size = len;
  

•   exp_info.flags = O_RDWR;
  

I think that the flags should be provided when requesting the allocation like it is done in DRM or V4L2. For me DMA_HEAP_VALID_FLAGS = (O_CLOEXEC | O_ACCMODE).

So something like done in udmabuf?

https://elixir.bootlin.com/linux/v5.1-rc1/source/include/uapi/linux/udmabuf....

I think that can be arranged.

I have in mind what is done by DRM: https://elixir.bootlin.com/linux/v5.1-rc1/source/include/uapi/drm/drm.h#L707

V4L2 does the same but without redefine the flags (which is better)

That would mean we would need a whole flag word passed in just for file flags when I only ever see one bit being useful(O_CLOEXEC or not). Do you see any situation where we need more than default O_RDWR and optional O_CLOEXEC for a dma-buf file?

Andrew

Benjamin

...

John,

This might be a good reason to move the dma_buf_fd() call below out of the heap and back into the core. That way the file exporting flags can be common and core handled. I don't think it would complicate the error handling any as we only need to dma_buf_put(dmabuf) in the core on failure and the heap specific cleanup will happen for us.

Andrew

...

Benjamin

Benjamin

...

•   exp_info.priv = &helper_buffer->heap_buffer;
  

•   dmabuf = dma_buf_export(&exp_info);
  

•   if (IS_ERR(dmabuf)) {
  

•           ret = PTR_ERR(dmabuf);
  

•           goto free_pages;
  

•   }
  

•   helper_buffer->heap_buffer.dmabuf = dmabuf;
  

•   helper_buffer->priv_virt = pages;
  

•   ret = dma_buf_fd(dmabuf, O_CLOEXEC);
  

•   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, pages, nr_pages);
  

+free_buf:

•   kfree(helper_buffer);
  

•   return ret;
  

+}

+static 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_cma_heaps(void) +{

•   cma_for_each_area(__add_cma_heap, NULL);
  

•   return 0;
  

+}

+device_initcall(add_cma_heaps);

2.7.4

On 3/28/19 7:16 PM, John Stultz wrote:

This adds a CMA heap, which allows userspace to allocate a dma-buf of contiguous memory out of a CMA region.

This code is an evolution of the Android ION implementation, so thanks to its original author and maintainters: Benjamin Gaignard, Laura Abbott, and others!

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: Xu YiPing xuyiping@hisilicon.com Cc: "Chenfeng (puck)" puck.chen@hisilicon.com Cc: butao butao@hisilicon.com Cc: "Xiaqing (A)" saberlily.xia@hisilicon.com Cc: Yudongbin yudongbin@hisilicon.com Cc: Christoph Hellwig hch@infradead.org Cc: Chenbo Feng fengc@google.com Cc: Alistair Strachan astrachan@google.com Cc: dri-devel@lists.freedesktop.org Signed-off-by: John Stultz john.stultz@linaro.org

---

v2:

• Switch allocate to return dmabuf fd
• Simplify init code
• Checkpatch fixups

v3:

• Switch to inline function for to_cma_heap()
• Minor cleanups suggested by Brian
• Fold in new registration style from Andrew
• Folded in changes from Andrew to use simplified page list from the heap helpers

---

drivers/dma-buf/heaps/Kconfig | 8 ++ drivers/dma-buf/heaps/Makefile | 1 + drivers/dma-buf/heaps/cma_heap.c | 170 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 179 insertions(+) create mode 100644 drivers/dma-buf/heaps/cma_heap.c

diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig index 2050527..a5eef06 100644 --- a/drivers/dma-buf/heaps/Kconfig +++ b/drivers/dma-buf/heaps/Kconfig @@ -4,3 +4,11 @@ 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.
  

diff --git a/drivers/dma-buf/heaps/Makefile b/drivers/dma-buf/heaps/Makefile index d1808ec..6e54cde 100644 --- a/drivers/dma-buf/heaps/Makefile +++ b/drivers/dma-buf/heaps/Makefile @@ -1,3 +1,4 @@ # 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 diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c new file mode 100644 index 0000000..f4485c60 --- /dev/null +++ b/drivers/dma-buf/heaps/cma_heap.c @@ -0,0 +1,170 @@ +// 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/device.h> +#include <linux/dma-buf.h> +#include <linux/dma-heap.h> +#include <linux/slab.h> +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/cma.h> +#include <linux/scatterlist.h> +#include <linux/highmem.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_data(buffer->heap_buffer.heap);
• struct page *pages = buffer->priv_virt;
• unsigned long nr_pages;
• nr_pages = buffer->heap_buffer.size >> PAGE_SHIFT;

Could also use the count in helper_buffer->pagecount.

• /* free page list */
• kfree(buffer->pages);
• /* release memory */
• cma_release(cma_heap->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 flags)
  

+{

• struct cma_heap *cma_heap = dma_heap_get_data(heap);
• struct heap_helper_buffer *helper_buffer;
• struct page *pages;
• size_t size = PAGE_ALIGN(len);
• unsigned long nr_pages = size >> PAGE_SHIFT;
• unsigned long align = get_order(size);
• DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
• 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->heap_buffer.flags = flags;
• helper_buffer->heap_buffer.heap = heap;
• helper_buffer->heap_buffer.size = len;
• pages = cma_alloc(cma_heap->cma, nr_pages, align, false);
• if (!pages)

• goto free_buf;
  

• if (PageHighMem(pages)) {

Can the allocated pages list cross the high mem line?

If so then:

foreach(nr_pages) { if (PageHighMem(page)) clear_highpage(page); else clear_page(page_address(page)); }

If not still should use clear_highpage() below.

Andrew

• unsigned long nr_clear_pages = nr_pages;
  

• struct page *page = pages;
  

• while (nr_clear_pages > 0) {
  

• 	void *vaddr = kmap_atomic(page);
  

• 	memset(vaddr, 0, PAGE_SIZE);
  

• 	kunmap_atomic(vaddr);
  

• 	page++;
  

• 	nr_clear_pages--;
  

• }
  

• } else {

• memset(page_address(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] = &pages[pg];
  

• if (!helper_buffer->pages[pg])
  

• 	goto free_pages;
  

• }
• /* create the dmabuf */
• exp_info.ops = &heap_helper_ops;
• exp_info.size = len;
• exp_info.flags = O_RDWR;
• exp_info.priv = &helper_buffer->heap_buffer;
• dmabuf = dma_buf_export(&exp_info);
• if (IS_ERR(dmabuf)) {

• ret = PTR_ERR(dmabuf);
  

• goto free_pages;
  

• }
• helper_buffer->heap_buffer.dmabuf = dmabuf;
• helper_buffer->priv_virt = pages;
• ret = dma_buf_fd(dmabuf, O_CLOEXEC);
• 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, pages, nr_pages);

+free_buf:

• kfree(helper_buffer);
• return ret;

+}

+static 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_cma_heaps(void) +{

• cma_for_each_area(__add_cma_heap, NULL);
• return 0;

+} +device_initcall(add_cma_heaps);