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author | Volodymyr Babchuk <vlad.babchuk@gmail.com> | 2017-11-29 14:48:37 +0200 |
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committer | Jens Wiklander <jens.wiklander@linaro.org> | 2017-12-15 13:36:18 +0100 |
commit | 217e0250cccb9e54d457991446cd3fab413085e1 (patch) | |
tree | 42906632546d8fe35890ac41a019f641fc1055a2 | |
parent | f58e236c9d665ad0af99c908de4a9b6f07e74dda (diff) | |
download | linux-stable-217e0250cccb9e54d457991446cd3fab413085e1.tar.gz linux-stable-217e0250cccb9e54d457991446cd3fab413085e1.tar.bz2 linux-stable-217e0250cccb9e54d457991446cd3fab413085e1.zip |
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: Volodymyr Babchuk <vlad.babchuk@gmail.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
-rw-r--r-- | drivers/tee/tee_core.c | 40 | ||||
-rw-r--r-- | drivers/tee/tee_private.h | 3 | ||||
-rw-r--r-- | drivers/tee/tee_shm.c | 7 | ||||
-rw-r--r-- | include/linux/tee_drv.h | 7 |
4 files changed, 48 insertions, 9 deletions
diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index 295910f5cdd0..3d49ac2e3c84 100644 --- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -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 @@ err: 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; } diff --git a/drivers/tee/tee_private.h b/drivers/tee/tee_private.h index 2bc2b5ab1661..85d99d621603 100644 --- a/drivers/tee/tee_private.h +++ b/drivers/tee/tee_private.h @@ -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*/ diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c index 11d11a46d86e..ba02a15eefcb 100644 --- a/drivers/tee/tee_shm.c +++ b/drivers/tee/tee_shm.c @@ -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 @@ err: kfree(shm->pages); } kfree(shm); + teedev_ctx_put(ctx); tee_device_put(teedev); return ret; } diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h index 0f86a480c204..157e8d06bf49 100644 --- a/include/linux/tee_drv.h +++ b/include/linux/tee_drv.h @@ -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 { |