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Commit 217e0250 authored by Volodymyr Babchuk's avatar Volodymyr Babchuk Committed by Jens Wiklander
Browse files

tee: use reference counting for tee_context 



We need to ensure that tee_context is present until last
shared buffer will be freed.

Signed-off-by: default avatarVolodymyr Babchuk <vlad.babchuk@gmail.com>
Signed-off-by: default avatarJens Wiklander <jens.wiklander@linaro.org>
parent f58e236c

drivers/tee/tee_core.c

+31 −9
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ static int tee_open(struct inode *inode, struct file *filp) 
		goto err;

	}



	kref_init(&ctx->refcount);

	ctx->teedev = teedev;

	INIT_LIST_HEAD(&ctx->list_shm);

	filp->private_data = ctx;
@@ -68,19 +69,40 @@ static int tee_open(struct inode *inode, struct file *filp) 
	return rc;

}



static int tee_release(struct inode *inode, struct file *filp)

void teedev_ctx_get(struct tee_context *ctx)

{

	struct tee_context *ctx = filp->private_data;

	struct tee_device *teedev = ctx->teedev;

	struct tee_shm *shm;

	if (ctx->releasing)

		return;



	kref_get(&ctx->refcount);

}



static void teedev_ctx_release(struct kref *ref)

{

	struct tee_context *ctx = container_of(ref, struct tee_context,

					       refcount);

	ctx->releasing = true;

	ctx->teedev->desc->ops->release(ctx);

	mutex_lock(&ctx->teedev->mutex);

	list_for_each_entry(shm, &ctx->list_shm, link)

		shm->ctx = NULL;

	mutex_unlock(&ctx->teedev->mutex);

	kfree(ctx);

	tee_device_put(teedev);

}



void teedev_ctx_put(struct tee_context *ctx)

{

	if (ctx->releasing)

		return;



	kref_put(&ctx->refcount, teedev_ctx_release);

}



static void teedev_close_context(struct tee_context *ctx)

{

	tee_device_put(ctx->teedev);

	teedev_ctx_put(ctx);

}



static int tee_release(struct inode *inode, struct file *filp)

{

	teedev_close_context(filp->private_data);

	return 0;

}

drivers/tee/tee_private.h

+3 −0
Original line number Diff line number Diff line
@@ -73,4 +73,7 @@ int tee_shm_get_fd(struct tee_shm *shm); 
bool tee_device_get(struct tee_device *teedev);

void tee_device_put(struct tee_device *teedev);



void teedev_ctx_get(struct tee_context *ctx);

void teedev_ctx_put(struct tee_context *ctx);



#endif /*TEE_PRIVATE_H*/

drivers/tee/tee_shm.c

+7 −0
Original line number Diff line number Diff line
@@ -53,6 +53,9 @@ static void tee_shm_release(struct tee_shm *shm) 
		kfree(shm->pages);

	}



	if (shm->ctx)

		teedev_ctx_put(shm->ctx);



	kfree(shm);



	tee_device_put(teedev);
@@ -187,6 +190,7 @@ struct tee_shm *__tee_shm_alloc(struct tee_context *ctx, 
	}



	if (ctx) {

		teedev_ctx_get(ctx);

		mutex_lock(&teedev->mutex);

		list_add_tail(&shm->link, &ctx->list_shm);

		mutex_unlock(&teedev->mutex);
@@ -253,6 +257,8 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr, 
		return ERR_PTR(-ENOTSUPP);

	}



	teedev_ctx_get(ctx);



	shm = kzalloc(sizeof(*shm), GFP_KERNEL);

	if (!shm) {

		ret = ERR_PTR(-ENOMEM);
@@ -334,6 +340,7 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr, 
		kfree(shm->pages);

	}

	kfree(shm);

	teedev_ctx_put(ctx);

	tee_device_put(teedev);

	return ret;

}

include/linux/tee_drv.h

+7 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 


#include <linux/types.h>

#include <linux/idr.h>

#include <linux/kref.h>

#include <linux/list.h>

#include <linux/tee.h>
@@ -42,11 +43,17 @@ struct tee_shm_pool; 
 * @teedev:	pointer to this drivers struct tee_device

 * @list_shm:	List of shared memory object owned by this context

 * @data:	driver specific context data, managed by the driver

 * @refcount:	reference counter for this structure

 * @releasing:  flag that indicates if context is being released right now.

 *		It is needed to break circular dependency on context during

 *              shared memory release.

 */

struct tee_context {

	struct tee_device *teedev;

	struct list_head list_shm;

	void *data;

	struct kref refcount;

	bool releasing;

};



struct tee_param_memref {