linux-kernel - Re: [char-misc-next 6/6] mei: bus: add client dma interface

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Message-ID: <YB6sIi61X5p6Dq6y@kroah.com>
Date:   Sat, 6 Feb 2021 15:48:02 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Tomas Winkler <tomas.winkler@...el.com>
Cc:     Alexander Usyskin <alexander.usyskin@...el.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [char-misc-next 6/6] mei: bus: add client dma interface

On Sat, Feb 06, 2021 at 04:43:25PM +0200, Tomas Winkler wrote:
> From: Alexander Usyskin <alexander.usyskin@...el.com>
> 
> Expose the client dma mapping via mei client
> bus interface.
> 
> Signed-off-by: Alexander Usyskin <alexander.usyskin@...el.com>
> Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
> ---
>  drivers/misc/mei/bus.c     | 46 ++++++++++++++++++++++++++++++++++++++
>  drivers/misc/mei/hw.h      |  5 +++++
>  include/linux/mei_cl_bus.h |  3 +++
>  3 files changed, 54 insertions(+)
> 
> diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
> index 34fb5e541fe5..d430710a5fe5 100644
> --- a/drivers/misc/mei/bus.c
> +++ b/drivers/misc/mei/bus.c
> @@ -636,6 +636,52 @@ static void mei_cl_bus_vtag_free(struct mei_cl_device *cldev)
>  	kfree(cl_vtag);
>  }
>  
> +void *mei_cldev_dma_map(struct mei_cl_device *cldev, u8 buffer_id, size_t size)
> +{
> +	struct mei_device *bus;
> +	struct mei_cl *cl;
> +	int ret;
> +
> +	if (!cldev || !buffer_id || !size)
> +		return ERR_PTR(-EINVAL);
> +
> +	if (!IS_ALIGNED(size, MEI_FW_PAGE_SIZE)) {
> +		dev_err(&cldev->dev, "Map size should be aligned to %lu\n",
> +			MEI_FW_PAGE_SIZE);
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	cl = cldev->cl;
> +	bus = cldev->bus;
> +
> +	mutex_lock(&bus->device_lock);
> +	ret = mei_cl_dma_alloc_and_map(cl, NULL, buffer_id, size);
> +	mutex_unlock(&bus->device_lock);
> +	if (ret)
> +		return ERR_PTR(ret);
> +	return cl->dma.vaddr;
> +}
> +EXPORT_SYMBOL_GPL(mei_cldev_dma_map);

Why are you exporting symbols without a user of them?

That's a sure way to get them removed by someone right after this lands
in the tree :)

Please only add infrastructure for when you have a real user.

thanks,

greg k-h