[PATCH v2 3/3] dma-buf: heaps: cma: charge each cma heap's dmem

[Eric Chanudet <echanude@redhat.com>]

The cma dma-buf heaps let userspace allocate buffers in CMA regions
without enforcing limits. Since each cma region registers in dmem,
charge against it when allocating a buffer in a cma heap.

Signed-off-by: Eric Chanudet <echanude@redhat.com>
---
 drivers/dma-buf/heaps/cma_heap.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c
index 49cc45fb42dd7200c3c14384bcfdbe85323454b1..bbd4f9495808da19256d97bd6a4dca3e1b0a30a0 100644
--- a/drivers/dma-buf/heaps/cma_heap.c
+++ b/drivers/dma-buf/heaps/cma_heap.c
@@ -27,6 +27,7 @@
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
+#include <linux/cgroup_dmem.h>
 
 #define DEFAULT_CMA_NAME "default_cma_region"
 
@@ -58,6 +59,7 @@ struct cma_heap_buffer {
 	pgoff_t pagecount;
 	int vmap_cnt;
 	void *vaddr;
+	struct dmem_cgroup_pool_state *pool;
 };
 
 struct dma_heap_attachment {
@@ -276,6 +278,7 @@ static void cma_heap_dma_buf_release(struct dma_buf *dmabuf)
 	kfree(buffer->pages);
 	/* release memory */
 	cma_release(cma_heap->cma, buffer->cma_pages, buffer->pagecount);
+	dmem_cgroup_uncharge(buffer->pool, buffer->len);
 	kfree(buffer);
 }
 
@@ -319,9 +322,17 @@ static struct dma_buf *cma_heap_allocate(struct dma_heap *heap,
 	if (align > CONFIG_CMA_ALIGNMENT)
 		align = CONFIG_CMA_ALIGNMENT;
 
+	if (mem_accounting) {
+		ret = dmem_cgroup_try_charge(
+			cma_get_dmem_cgroup_region(cma_heap->cma), size,
+			&buffer->pool, NULL);
+		if (ret)
+			goto free_buffer;
+	}
+
 	cma_pages = cma_alloc(cma_heap->cma, pagecount, align, false);
 	if (!cma_pages)
-		goto free_buffer;
+		goto uncharge_cgroup;
 
 	/* Clear the cma pages */
 	if (PageHighMem(cma_pages)) {
@@ -376,6 +387,8 @@ static struct dma_buf *cma_heap_allocate(struct dma_heap *heap,
 	kfree(buffer->pages);
 free_cma:
 	cma_release(cma_heap->cma, cma_pages, pagecount);
+uncharge_cgroup:
+	dmem_cgroup_uncharge(buffer->pool, size);
 free_buffer:
 	kfree(buffer);
 

-- 
2.52.0