tee: remove linked list of struct tee_shm

mainline inclusion
from mainline-v5.7-rc1
commit 59a135f6
category: cleanup
bugzilla: NA
CVE: NA

Prepare for fixing CVE-2021-44733.
--------------------------------

Removes list_shm from struct tee_context since the linked list isn't used
any longer.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Conflicts:
  drivers/tee/tee_core.c
[yyl: adjust context]
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>

drivers/tee/tee_core.c

@@ -56,7 +56,6 @@ static int tee_open(struct inode *inode, struct file *filp)
 
 	kref_init(&ctx->refcount);
 	ctx->teedev = teedev;
-	INIT_LIST_HEAD(&ctx->list_shm);
 	filp->private_data = ctx;
 	rc = teedev->desc->ops->open(ctx);
 	if (rc)

drivers/tee/tee_shm.c

@@ -26,8 +26,6 @@ static void tee_shm_release(struct tee_shm *shm)
 
 	mutex_lock(&teedev->mutex);
 	idr_remove(&teedev->idr, shm->id);
-	if (shm->ctx)
-		list_del(&shm->link);
 	mutex_unlock(&teedev->mutex);
 
 	if (shm->flags & TEE_SHM_POOL) {
@@ -183,12 +181,8 @@ static struct tee_shm *__tee_shm_alloc(struct tee_context *ctx,
 		}
 	}
 
-	if (ctx) {
+	if (ctx)
 		teedev_ctx_get(ctx);
-		mutex_lock(&teedev->mutex);
-		list_add_tail(&shm->link, &ctx->list_shm);
-		mutex_unlock(&teedev->mutex);
-	}
 
 	return shm;
 err_rem:
@@ -315,10 +309,6 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
 		}
 	}
 
-	mutex_lock(&teedev->mutex);
-	list_add_tail(&shm->link, &ctx->list_shm);
-	mutex_unlock(&teedev->mutex);
-
 	return shm;
 err:
 	if (shm) {

include/linux/tee_drv.h

@@ -50,7 +50,6 @@ struct tee_shm_pool;
  */
 struct tee_context {
 	struct tee_device *teedev;
-	struct list_head list_shm;
 	void *data;
 	struct kref refcount;
 	bool releasing;
@@ -170,7 +169,6 @@ void tee_device_unregister(struct tee_device *teedev);
  * struct tee_shm - shared memory object
  * @teedev:	device used to allocate the object
  * @ctx:	context using the object, if NULL the context is gone
- * @link	link element
  * @paddr:	physical address of the shared memory
  * @kaddr:	virtual address of the shared memory
  * @size:	size of shared memory
@@ -187,7 +185,6 @@ void tee_device_unregister(struct tee_device *teedev);
 struct tee_shm {
 	struct tee_device *teedev;
 	struct tee_context *ctx;
-	struct list_head link;
 	phys_addr_t paddr;
 	void *kaddr;
 	size_t size;