[PATCH v7 2/5] dma-buf: heaps: Move heap-helper logic into the cma_heap implementation

John Stultz
2020-11-21T23:50:29Z

Since the heap-helpers logic ended up not being as generic as
hoped, move the heap-helpers dma_buf_ops implementations into
the cma_heap directly.

This will allow us to remove the heap_helpers code in a following
patch.

Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Liam Mark <lmark@codeaurora.org>
Cc: Laura Abbott <labbott@kernel.org>
Cc: Brian Starkey <Brian.Starkey@arm.com>
Cc: Hridya Valsaraju <hridya@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sandeep Patil <sspatil@google.com>
Cc: Daniel Mentz <danielmentz@google.com>
Cc: Chris Goldsworthy <cgoldswo@codeaurora.org>
Cc: Ørjan Eide <orjan.eide@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Ezequiel Garcia <ezequiel@collabora.com>
Cc: Simon Ser <contact@emersion.fr>
Cc: James Jones <jajones@nvidia.com>
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Brian Starkey <brian.starkey@arm.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
---
v2:
* Fix unused return value and locking issue Reported-by:
kernel test robot <lkp@intel.com>
Julia Lawall <julia.lawall@inria.fr>
* Make cma_heap_buf_ops static suggested by
kernel test robot <lkp@intel.com>
* Fix uninitialized return in cma Reported-by:
kernel test robot <lkp@intel.com>
* Minor cleanups
v3:
* Use the new sgtable mapping functions, as Suggested-by:
Daniel Mentz <danielmentz@google.com>
v4:
* Spelling fix suggested by BrianS
v6:
* Fixups against drm-misc-next
v7:
* Redo the incorrect dma-buf-map adaptation in the last revision
---
drivers/dma-buf/heaps/cma_heap.c | 319 ++++++++++++++++++++++++++-----
1 file changed, 270 insertions(+), 49 deletions(-)

diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c
index e55384dc115b..05aaa4f29397 100644
--- a/drivers/dma-buf/heaps/cma_heap.c
+++ b/drivers/dma-buf/heaps/cma_heap.c
@@ -2,76 +2,295 @@
/*
* DMABUF CMA heap exporter
*
- * Copyright (C) 2012, 2019 Linaro Ltd.
+ * Copyright (C) 2012, 2019, 2020 Linaro Ltd.
* Author: <benjamin.gaignard@linaro.org> for ST-Ericsson.
+ *
+ * Also utilizing parts of Andrew Davis' SRAM heap:
+ * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
+ * Andrew F. Davis <afd@ti.com>
*/
-
#include <linux/cma.h>
-#include <linux/device.h>
#include <linux/dma-buf.h>
#include <linux/dma-heap.h>
#include <linux/dma-map-ops.h>
#include <linux/err.h>
-#include <linux/errno.h>
#include <linux/highmem.h>
+#include <linux/io.h>
+#include <linux/mm.h>
#include <linux/module.h>
-#include <linux/slab.h>
#include <linux/scatterlist.h>
-#include <linux/sched/signal.h>
+#include <linux/slab.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_buffer {
+ struct cma_heap *heap;
+ struct list_head attachments;
+ struct mutex lock;
+ unsigned long len;
+ struct page *cma_pages;
+ struct page **pages;
+ pgoff_t pagecount;
+ int vmap_cnt;
+ void *vaddr;
+};
+
+struct dma_heap_attachment {
+ struct device *dev;
+ struct sg_table table;
+ struct list_head list;
+};
+
+static int cma_heap_attach(struct dma_buf *dmabuf,
+ struct dma_buf_attachment *attachment)
{
- struct cma_heap *cma_heap = dma_heap_get_drvdata(buffer->heap);
- unsigned long nr_pages = buffer->pagecount;
- struct page *cma_pages = buffer->priv_virt;
+ struct cma_heap_buffer *buffer = dmabuf->priv;
+ struct dma_heap_attachment *a;
+ int ret;

- /* free page list */
- kfree(buffer->pages);
- /* release memory */
- cma_release(cma_heap->cma, cma_pages, nr_pages);
+ 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 cma_heap_detach(struct dma_buf *dmabuf,
+ struct dma_buf_attachment *attachment)
+{
+ struct cma_heap_buffer *buffer = dmabuf->priv;
+ struct dma_heap_attachment *a = attachment->priv;
+
+ mutex_lock(&buffer->lock);
+ list_del(&a->list);
+ mutex_unlock(&buffer->lock);
+
+ sg_free_table(&a->table);
+ kfree(a);
+}
+
+static struct sg_table *cma_heap_map_dma_buf(struct dma_buf_attachment *attachment,
+ enum dma_data_direction direction)
+{
+ struct dma_heap_attachment *a = attachment->priv;
+ struct sg_table *table = &a->table;
+ int ret;
+
+ ret = dma_map_sgtable(attachment->dev, table, direction, 0);
+ if (ret)
+ return ERR_PTR(-ENOMEM);
+ return table;
+}
+
+static void cma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment,
+ struct sg_table *table,
+ enum dma_data_direction direction)
+{
+ dma_unmap_sgtable(attachment->dev, table, direction, 0);
+}
+
+static int cma_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
+ enum dma_data_direction direction)
+{
+ struct cma_heap_buffer *buffer = dmabuf->priv;
+ struct dma_heap_attachment *a;
+
+ if (buffer->vmap_cnt)
+ invalidate_kernel_vmap_range(buffer->vaddr, buffer->len);
+
+ mutex_lock(&buffer->lock);
+ list_for_each_entry(a, &buffer->attachments, list) {
+ dma_sync_sgtable_for_cpu(a->dev, &a->table, direction);
+ }
+ mutex_unlock(&buffer->lock);
+
+ return 0;
+}
+
+static int cma_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
+ enum dma_data_direction direction)
+{
+ struct cma_heap_buffer *buffer = dmabuf->priv;
+ struct dma_heap_attachment *a;
+
+ if (buffer->vmap_cnt)
+ flush_kernel_vmap_range(buffer->vaddr, buffer->len);
+
+ mutex_lock(&buffer->lock);
+ list_for_each_entry(a, &buffer->attachments, list) {
+ dma_sync_sgtable_for_device(a->dev, &a->table, direction);
+ }
+ mutex_unlock(&buffer->lock);
+
+ return 0;
+}
+
+static vm_fault_t cma_heap_vm_fault(struct vm_fault *vmf)
+{
+ struct vm_area_struct *vma = vmf->vma;
+ struct cma_heap_buffer *buffer = vma->vm_private_data;
+
+ if (vmf->pgoff > buffer->pagecount)
+ return VM_FAULT_SIGBUS;
+
+ vmf->page = buffer->pages[vmf->pgoff];
+ get_page(vmf->page);
+
+ return 0;
+}
+
+static const struct vm_operations_struct dma_heap_vm_ops = {
+ .fault = cma_heap_vm_fault,
+};
+
+static int cma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
+{
+ struct cma_heap_buffer *buffer = dmabuf->priv;
+
+ 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 *cma_heap_do_vmap(struct cma_heap_buffer *buffer)
+{
+ void *vaddr;
+
+ vaddr = vmap(buffer->pages, buffer->pagecount, VM_MAP, PAGE_KERNEL);
+ if (!vaddr)
+ return ERR_PTR(-ENOMEM);
+
+ return vaddr;
+}
+
+static int cma_heap_vmap(struct dma_buf *dmabuf, struct dma_buf_map *map)
+{
+ struct cma_heap_buffer *buffer = dmabuf->priv;
+ void *vaddr;
+ int ret = 0;
+
+ mutex_lock(&buffer->lock);
+ if (buffer->vmap_cnt) {
+ buffer->vmap_cnt++;
+ dma_buf_map_set_vaddr(map, buffer->vaddr);
+ goto out;
+ }
+
+ vaddr = cma_heap_do_vmap(buffer);
+ if (IS_ERR(vaddr)) {
+ ret = PTR_ERR(vaddr);
+ goto out;
+ }
+ buffer->vaddr = vaddr;
+ buffer->vmap_cnt++;
+ dma_buf_map_set_vaddr(map, buffer->vaddr);
+out:
+ mutex_unlock(&buffer->lock);
+
+ return ret;
+}
+
+static void cma_heap_vunmap(struct dma_buf *dmabuf, struct dma_buf_map *map)
+{
+ struct cma_heap_buffer *buffer = dmabuf->priv;
+
+ mutex_lock(&buffer->lock);
+ if (!--buffer->vmap_cnt) {
+ vunmap(buffer->vaddr);
+ buffer->vaddr = NULL;
+ }
+ mutex_unlock(&buffer->lock);
+ dma_buf_map_clear(map);
+}
+
+static void cma_heap_dma_buf_release(struct dma_buf *dmabuf)
+{
+ struct cma_heap_buffer *buffer = dmabuf->priv;
+ struct cma_heap *cma_heap = buffer->heap;
+
+ if (buffer->vmap_cnt > 0) {
+ WARN(1, "%s: buffer still mapped in the kernel\n", __func__);
+ vunmap(buffer->vaddr);
+ buffer->vaddr = NULL;
+ }
+
+ cma_release(cma_heap->cma, buffer->cma_pages, buffer->pagecount);
kfree(buffer);
}

-/* dmabuf heap CMA operations functions */
+static const struct dma_buf_ops cma_heap_buf_ops = {
+ .attach = cma_heap_attach,
+ .detach = cma_heap_detach,
+ .map_dma_buf = cma_heap_map_dma_buf,
+ .unmap_dma_buf = cma_heap_unmap_dma_buf,
+ .begin_cpu_access = cma_heap_dma_buf_begin_cpu_access,
+ .end_cpu_access = cma_heap_dma_buf_end_cpu_access,
+ .mmap = cma_heap_mmap,
+ .vmap = cma_heap_vmap,
+ .vunmap = cma_heap_vunmap,
+ .release = cma_heap_dma_buf_release,
+};
+
static int cma_heap_allocate(struct dma_heap *heap,
- unsigned long len,
- unsigned long fd_flags,
- unsigned long heap_flags)
+ 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;
+ struct cma_heap_buffer *buffer;
+ DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
size_t size = PAGE_ALIGN(len);
- unsigned long nr_pages = size >> PAGE_SHIFT;
+ pgoff_t pagecount = size >> PAGE_SHIFT;
unsigned long align = get_order(size);
+ struct page *cma_pages;
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)
+ buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
+ if (!buffer)
return -ENOMEM;

- init_heap_helper_buffer(helper_buffer, cma_heap_free);
- helper_buffer->heap = heap;
- helper_buffer->size = len;
+ INIT_LIST_HEAD(&buffer->attachments);
+ mutex_init(&buffer->lock);
+ buffer->len = size;
+
+ if (align > CONFIG_CMA_ALIGNMENT)
+ align = CONFIG_CMA_ALIGNMENT;

- cma_pages = cma_alloc(cma_heap->cma, nr_pages, align, false);
+ cma_pages = cma_alloc(cma_heap->cma, pagecount, align, false);
if (!cma_pages)
- goto free_buf;
+ goto free_buffer;

+ /* Clear the cma pages */
if (PageHighMem(cma_pages)) {
- unsigned long nr_clear_pages = nr_pages;
+ unsigned long nr_clear_pages = pagecount;
struct page *page = cma_pages;

while (nr_clear_pages > 0) {
@@ -85,7 +304,6 @@ static int cma_heap_allocate(struct dma_heap *heap,
*/
if (fatal_signal_pending(current))
goto free_cma;
-
page++;
nr_clear_pages--;
}
@@ -93,28 +311,30 @@ static int cma_heap_allocate(struct dma_heap *heap,
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) {
+ buffer->pages = kmalloc_array(pagecount, sizeof(*buffer->pages), GFP_KERNEL);
+ if (!buffer->pages) {
ret = -ENOMEM;
goto free_cma;
}

- for (pg = 0; pg < helper_buffer->pagecount; pg++)
- helper_buffer->pages[pg] = &cma_pages[pg];
+ for (pg = 0; pg < pagecount; pg++)
+ buffer->pages[pg] = &cma_pages[pg];
+
+ buffer->cma_pages = cma_pages;
+ buffer->heap = cma_heap;
+ buffer->pagecount = pagecount;

/* create the dmabuf */
- dmabuf = heap_helper_export_dmabuf(helper_buffer, fd_flags);
+ exp_info.ops = &cma_heap_buf_ops;
+ exp_info.size = buffer->len;
+ exp_info.flags = fd_flags;
+ exp_info.priv = buffer;
+ dmabuf = dma_buf_export(&exp_info);
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);
@@ -125,11 +345,12 @@ static int cma_heap_allocate(struct dma_heap *heap,
return ret;

free_pages:
- kfree(helper_buffer->pages);
+ kfree(buffer->pages);
free_cma:
- cma_release(cma_heap->cma, cma_pages, nr_pages);
-free_buf:
- kfree(helper_buffer);
+ cma_release(cma_heap->cma, cma_pages, pagecount);
+free_buffer:
+ kfree(buffer);
+
return ret;
}

--
2.17.1