Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 253542f2 authored by Liam Mark's avatar Liam Mark Committed by Suren Baghdasaryan
Browse files

ANDROID: GKI: dma-buf: Add support to set a destructor on a dma-buf 



dma-buf destructor support is useful as it allows clients an opportunity
to undo any attributes, such as security attributes, they have applied to
the dma-buf's memory.

The destructor is called when the dma-buf is freed, if the destructor
returns an error the dma-buf's exporter release function is not called in
order to ensure that memory which has not been properly cleaned up isn't
returned to the system.

Signed-off-by: default avatarLiam Mark <lmark@codeaurora.org>
Signed-off-by: default avatarSwathi Sridhar <swatsrid@codeaurora.org>

[surenb: cherry-picked from:
3af4db15 "dma-buf: Add support to set a destructor on a dma-buf"]

Bug: 150611569
Test: build
Signed-off-by: default avatarSuren Baghdasaryan <surenb@google.com>
Change-Id: I2d435b99fb9b1747bc1b32a4e0d484957614a5a3
parent cea23cb7

drivers/dma-buf/dma-buf.c

+10 −2
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ static struct file_system_type dma_buf_fs_type = { 
static int dma_buf_release(struct inode *inode, struct file *file)

{

	struct dma_buf *dmabuf;

	int dtor_ret = 0;



	if (!is_dma_buf_file(file))

		return -EINVAL;
@@ -104,12 +105,19 @@ static int dma_buf_release(struct inode *inode, struct file *file) 
	 */

	BUG_ON(dmabuf->cb_shared.active || dmabuf->cb_excl.active);



	dmabuf->ops->release(dmabuf);



	mutex_lock(&db_list.lock);

	list_del(&dmabuf->list_node);

	mutex_unlock(&db_list.lock);



	if (dmabuf->dtor)

		dtor_ret = dmabuf->dtor(dmabuf, dmabuf->dtor_data);



	if (!dtor_ret)

		dmabuf->ops->release(dmabuf);

	else

		pr_warn_ratelimited("Leaking dmabuf %s because destructor failed error:%d\n",

				    dmabuf->name, dtor_ret);



	if (dmabuf->resv == (struct reservation_object *)&dmabuf[1])

		reservation_object_fini(dmabuf->resv);

include/linux/dma-buf.h

+28 −0
Original line number Diff line number Diff line
@@ -321,6 +321,18 @@ struct dma_buf_ops { 
	int (*get_flags)(struct dma_buf *dmabuf, unsigned long *flags);

};



/**

 * dma_buf_destructor - dma-buf destructor function

 * @dmabuf:	[in]	pointer to dma-buf

 * @dtor_data:	[in]	destructor data associated with this buffer

 *

 * The dma-buf destructor which is called when the dma-buf is freed.

 *

 * If the destructor returns an error the dma-buf's exporter release function

 * won't be called.

 */

typedef int (*dma_buf_destructor)(struct dma_buf *dmabuf, void *dtor_data);



/**

 * struct dma_buf - shared buffer object

 * @size: size of the buffer
@@ -377,6 +389,8 @@ struct dma_buf { 


		__poll_t active;

	} cb_excl, cb_shared;

	dma_buf_destructor dtor;

	void *dtor_data;

};



/**
@@ -486,4 +500,18 @@ int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *, 
void *dma_buf_vmap(struct dma_buf *);

void dma_buf_vunmap(struct dma_buf *, void *vaddr);

int dma_buf_get_flags(struct dma_buf *dmabuf, unsigned long *flags);



/**

 * dma_buf_set_destructor - set the dma-buf's destructor

 * @dmabuf:		[in]	pointer to dma-buf

 * @dma_buf_destructor	[in]	the destructor function

 * @dtor_data:		[in]	destructor data associated with this buffer

 */

static inline void dma_buf_set_destructor(struct dma_buf *dmabuf,

					  dma_buf_destructor dtor,

					  void *dtor_data)

{

	dmabuf->dtor = dtor;

	dmabuf->dtor_data = dtor_data;

}

#endif /* __DMA_BUF_H__ */