linux-kernel - Re: [PATCH 2/5] misc: fastrpc: Add secure device node support

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Date:   Thu, 25 Nov 2021 16:45:51 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Jeya R <jeyr@...eaurora.org>
Cc:     linux-arm-msm@...r.kernel.org, srinivas.kandagatla@...aro.org,
        linux-kernel@...r.kernel.org, fastrpc.upstream@....qualcomm.com
Subject: Re: [PATCH 2/5] misc: fastrpc: Add secure device node support

On Thu, Nov 25, 2021 at 07:45:41PM +0530, Jeya R wrote:
> Register and deregister secure device node. Check for device name during
> device open get proper channel context.
> 
> Signed-off-by: Jeya R <jeyr@...eaurora.org>
> ---
>  drivers/misc/fastrpc.c | 33 +++++++++++++++++++++++++++++++--
>  1 file changed, 31 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index 39aca77..0775554e 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -79,6 +79,7 @@
>  #define SENSORS_PD	(2)
>  
>  #define miscdev_to_cctx(d) container_of(d, struct fastrpc_channel_ctx, miscdev)
> +#define securedev_to_cctx(d) container_of(d, struct fastrpc_channel_ctx, securedev)
>  
>  static const char *domains[FASTRPC_DEV_MAX] = { "adsp", "mdsp",
>  						"sdsp", "cdsp"};
> @@ -213,6 +214,7 @@ struct fastrpc_channel_ctx {
>  	struct idr ctx_idr;
>  	struct list_head users;
>  	struct miscdevice miscdev;
> +	struct miscdevice securedev;
>  	struct kref refcount;

Wow, you now have 3 structures with reference counts all trying to
manage the same structure.  That's 2 more than you need.

This is not ok, please do not do that.

greg k-h