[PATCH RFC 12/12] media: videobuf2: Track buffer allocations through the dmem cgroup

[Maxime Ripard <mripard@kernel.org>]

The dmem cgroup allows to track any DMA memory allocation made by the
userspace. Let's charge our allocations in videobuf2 to enable proper
memory tracking.

Signed-off-by: Maxime Ripard <mripard@kernel.org>
---
 drivers/media/common/videobuf2/videobuf2-dma-contig.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/media/common/videobuf2/videobuf2-dma-contig.c b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
index a13ec569c82f6da2d977222b94af32e74c6c6c82..48384e18030812f4f89f1c225c38def2ac6aa3ca 100644
--- a/drivers/media/common/videobuf2/videobuf2-dma-contig.c
+++ b/drivers/media/common/videobuf2/videobuf2-dma-contig.c
@@ -8,10 +8,11 @@
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation.
  */
 
+#include <linux/cgroup_dmem.h>
 #include <linux/dma-buf.h>
 #include <linux/module.h>
 #include <linux/refcount.h>
 #include <linux/scatterlist.h>
 #include <linux/sched.h>
@@ -40,10 +41,14 @@ struct vb2_dc_buf {
 	struct sg_table			*sgt_base;
 
 	/* DMABUF related */
 	struct dma_buf_attachment	*db_attach;
 
+#ifdef CONFIG_CGROUP_DMEM
+	struct dmem_cgroup_pool_state	*cgroup_pool_state;
+#endif
+
 	struct vb2_buffer		*vb;
 	bool				non_coherent_mem;
 };
 
 /*********************************************/
@@ -169,10 +174,14 @@ static void vb2_dc_put(void *buf_priv)
 	struct vb2_dc_buf *buf = buf_priv;
 
 	if (!refcount_dec_and_test(&buf->refcount))
 		return;
 
+#ifdef CONFIG_CGROUP_DMEM
+	dmem_cgroup_uncharge(buf->cgroup_pool_state, buf->size);
+#endif
+
 	if (buf->non_coherent_mem) {
 		if (buf->vaddr)
 			dma_vunmap_noncontiguous(buf->dev, buf->vaddr);
 		dma_free_noncontiguous(buf->dev, buf->size,
 				       buf->dma_sgt, buf->dma_dir);
@@ -230,10 +239,11 @@ static int vb2_dc_alloc_non_coherent(struct vb2_dc_buf *buf)
 
 static void *vb2_dc_alloc(struct vb2_buffer *vb,
 			  struct device *dev,
 			  unsigned long size)
 {
+	struct dmem_cgroup_pool_state *pool;
 	struct vb2_dc_buf *buf;
 	int ret;
 
 	if (WARN_ON(!dev))
 		return ERR_PTR(-EINVAL);
@@ -249,25 +259,34 @@ static void *vb2_dc_alloc(struct vb2_buffer *vb,
 
 	buf->size = size;
 	/* Prevent the device from being released while the buffer is used */
 	buf->dev = get_device(dev);
 
+	ret = dmem_cgroup_try_charge(dma_get_dmem_cgroup_region(dev), size, &pool, NULL);
+	if (ret)
+		return ret;
+
 	if (buf->non_coherent_mem)
 		ret = vb2_dc_alloc_non_coherent(buf);
 	else
 		ret = vb2_dc_alloc_coherent(buf);
 
 	if (ret) {
 		dev_err(dev, "dma alloc of size %lu failed\n", size);
+		dmem_cgroup_uncharge(pool, size);
 		kfree(buf);
 		return ERR_PTR(-ENOMEM);
 	}
 
 	buf->handler.refcount = &buf->refcount;
 	buf->handler.put = vb2_dc_put;
 	buf->handler.arg = buf;
 
+#ifdef CONFIG_CGROUP_DMEM
+	buf->cgroup_pool_state = pool;
+#endif
+
 	refcount_set(&buf->refcount, 1);
 
 	return buf;
 }
 

-- 
2.48.1