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Subject[RFC PATCHv2 06/21] staging: android: ion: Call dma_map_sg for syncing and mapping
Date

Technically, calling dma_buf_map_attachment should return a buffer
properly dma_mapped. Add calls to dma_map_sg to begin_cpu_access to
ensure this happens. As a side effect, this lets Ion buffers take
advantage of the dma_buf sync ioctls.

Signed-off-by: Laura Abbott <labbott@redhat.com>
---
drivers/staging/android/ion/ion.c | 151 ++++++++++++++++++++++-----------
drivers/staging/android/ion/ion_priv.h | 1 +
2 files changed, 103 insertions(+), 49 deletions(-)

diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index 7dcb8a9..6aac935 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -162,6 +162,7 @@ static struct ion_buffer *ion_buffer_create(struct ion_heap *heap,
buffer->dev = dev;
buffer->size = len;
INIT_LIST_HEAD(&buffer->vmas);
+ INIT_LIST_HEAD(&buffer->attachments);
mutex_init(&buffer->lock);
/*
* this will set up dma addresses for the sglist -- it is not
@@ -796,10 +797,6 @@ void ion_client_destroy(struct ion_client *client)
}
EXPORT_SYMBOL(ion_client_destroy);

-static void ion_buffer_sync_for_device(struct ion_buffer *buffer,
- struct device *dev,
- enum dma_data_direction direction);
-
static struct sg_table *dup_sg_table(struct sg_table *table)
{
struct sg_table *new_table;
@@ -826,22 +823,89 @@ static struct sg_table *dup_sg_table(struct sg_table *table)
return new_table;
}

+static void free_duped_table(struct sg_table *table)
+{
+ sg_free_table(table);
+ kfree(table);
+}
+
+struct ion_dma_buf_attachment {
+ struct device *dev;
+ struct sg_table *table;
+ struct list_head list;
+};
+
+static int ion_dma_buf_attach(struct dma_buf *dmabuf, struct device *dev,
+ struct dma_buf_attachment *attachment)
+{
+ struct ion_dma_buf_attachment *a;
+ struct sg_table *table;
+ struct ion_buffer *buffer = dmabuf->priv;
+
+ a = kzalloc(sizeof(*a), GFP_KERNEL);
+ if (!a)
+ return -ENOMEM;
+
+ table = dup_sg_table(buffer->sg_table);
+ if (IS_ERR(table)) {
+ kfree(a);
+ return -ENOMEM;
+ }
+
+ a->table = table;
+ a->dev = 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 ion_dma_buf_detatch(struct dma_buf *dmabuf,
+ struct dma_buf_attachment *attachment)
+{
+ struct ion_dma_buf_attachment *a = attachment->priv;
+ struct ion_buffer *buffer = dmabuf->priv;
+
+ free_duped_table(a->table);
+ mutex_lock(&buffer->lock);
+ list_del(&a->list);
+ mutex_unlock(&buffer->lock);
+
+ kfree(a);
+}
+
+
static struct sg_table *ion_map_dma_buf(struct dma_buf_attachment *attachment,
enum dma_data_direction direction)
{
- struct dma_buf *dmabuf = attachment->dmabuf;
- struct ion_buffer *buffer = dmabuf->priv;
+ struct ion_dma_buf_attachment *a = attachment->priv;
+ struct sg_table *table;
+ int ret;
+
+ table = a->table;

- ion_buffer_sync_for_device(buffer, attachment->dev, direction);
- return dup_sg_table(buffer->sg_table);
+ if (!dma_map_sg(attachment->dev, table->sgl, table->nents,
+ direction)){
+ ret = -ENOMEM;
+ goto err;
+ }
+ return table;
+
+err:
+ free_duped_table(table);
+ return ERR_PTR(ret);
}

static void ion_unmap_dma_buf(struct dma_buf_attachment *attachment,
struct sg_table *table,
enum dma_data_direction direction)
{
- sg_free_table(table);
- kfree(table);
+ dma_unmap_sg(attachment->dev, table->sgl, table->nents, direction);
}

void ion_pages_sync_for_device(struct device *dev, struct page *page,
@@ -865,38 +929,6 @@ struct ion_vma_list {
struct vm_area_struct *vma;
};

-static void ion_buffer_sync_for_device(struct ion_buffer *buffer,
- struct device *dev,
- enum dma_data_direction dir)
-{
- struct ion_vma_list *vma_list;
- int pages = PAGE_ALIGN(buffer->size) / PAGE_SIZE;
- int i;
-
- pr_debug("%s: syncing for device %s\n", __func__,
- dev ? dev_name(dev) : "null");
-
- if (!ion_buffer_fault_user_mappings(buffer))
- return;
-
- mutex_lock(&buffer->lock);
- for (i = 0; i < pages; i++) {
- struct page *page = buffer->pages[i];
-
- if (ion_buffer_page_is_dirty(page))
- ion_pages_sync_for_device(dev, ion_buffer_page(page),
- PAGE_SIZE, dir);
-
- ion_buffer_page_clean(buffer->pages + i);
- }
- list_for_each_entry(vma_list, &buffer->vmas, list) {
- struct vm_area_struct *vma = vma_list->vma;
-
- zap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start);
- }
- mutex_unlock(&buffer->lock);
-}
-
static int ion_vm_fault(struct vm_fault *vmf)
{
struct ion_buffer *buffer = vmf->vma->vm_private_data;
@@ -1014,26 +1046,45 @@ static int ion_dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
{
struct ion_buffer *buffer = dmabuf->priv;
void *vaddr;
+ struct ion_dma_buf_attachment *a;

- if (!buffer->heap->ops->map_kernel) {
- pr_err("%s: map kernel is not implemented by this heap.\n",
- __func__);
- return -ENODEV;
+ /*
+ * TODO: Move this elsewhere because we don't always need a vaddr
+ */
+ if (buffer->heap->ops->map_kernel) {
+ mutex_lock(&buffer->lock);
+ vaddr = ion_buffer_kmap_get(buffer);
+ mutex_unlock(&buffer->lock);
}

+
mutex_lock(&buffer->lock);
- vaddr = ion_buffer_kmap_get(buffer);
+ list_for_each_entry(a, &buffer->attachments, list) {
+ dma_sync_sg_for_cpu(a->dev, a->table->sgl, a->table->nents,
+ DMA_BIDIRECTIONAL);
+ }
mutex_unlock(&buffer->lock);
- return PTR_ERR_OR_ZERO(vaddr);
+
+ return 0;
}

static int ion_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
enum dma_data_direction direction)
{
struct ion_buffer *buffer = dmabuf->priv;
+ struct ion_dma_buf_attachment *a;
+
+ if (buffer->heap->ops->map_kernel) {
+ mutex_lock(&buffer->lock);
+ ion_buffer_kmap_put(buffer);
+ mutex_unlock(&buffer->lock);
+ }

mutex_lock(&buffer->lock);
- ion_buffer_kmap_put(buffer);
+ list_for_each_entry(a, &buffer->attachments, list) {
+ dma_sync_sg_for_device(a->dev, a->table->sgl, a->table->nents,
+ DMA_BIDIRECTIONAL);
+ }
mutex_unlock(&buffer->lock);

return 0;
@@ -1044,6 +1095,8 @@ static const struct dma_buf_ops dma_buf_ops = {
.unmap_dma_buf = ion_unmap_dma_buf,
.mmap = ion_mmap,
.release = ion_dma_buf_release,
+ .attach = ion_dma_buf_attach,
+ .detach = ion_dma_buf_detatch,
.begin_cpu_access = ion_dma_buf_begin_cpu_access,
.end_cpu_access = ion_dma_buf_end_cpu_access,
.kmap_atomic = ion_dma_buf_kmap,
diff --git a/drivers/staging/android/ion/ion_priv.h b/drivers/staging/android/ion/ion_priv.h
index b09bc7c..297d99d 100644
--- a/drivers/staging/android/ion/ion_priv.h
+++ b/drivers/staging/android/ion/ion_priv.h
@@ -72,6 +72,7 @@ struct ion_buffer {
struct sg_table *sg_table;
struct page **pages;
struct list_head vmas;
+ struct list_head attachments;
/* used to track orphaned buffers */
int handle_count;
char task_comm[TASK_COMM_LEN];
--
2.7.4
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