Re: [PATCH v1] misc: fastrpc: Add support for multiple PD from one process

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Jul 03, 2024 at 12:22:00PM +0530, Ekansh Gupta wrote:
> @@ -268,6 +272,7 @@ struct fastrpc_channel_ctx {
>  	struct fastrpc_session_ctx session[FASTRPC_MAX_SESSIONS];
>  	spinlock_t lock;
>  	struct idr ctx_idr;
> +	struct ida dsp_pgid_ida;

You have an idr and an ida?  Why two different types for the same
driver?

>  	struct list_head users;
>  	struct kref refcount;
>  	/* Flag if dsp attributes are cached */
> @@ -299,6 +304,7 @@ struct fastrpc_user {
>  	struct fastrpc_buf *init_mem;
>  
>  	int tgid;
> +	int dsp_pgid;

Are you sure this fits in an int?

> +static int fastrpc_pgid_alloc(struct fastrpc_channel_ctx *cctx)
> +{
> +	int ret = -1;

No need to initialize this.

> +
> +	/* allocate unique id between MIN_FRPC_PGID and MAX_FRPC_PGID */
> +	ret = ida_alloc_range(&cctx->dsp_pgid_ida, MIN_FRPC_PGID,
> +					MAX_FRPC_PGID, GFP_ATOMIC);
> +	if (ret < 0)
> +		return -1;

Why is -1 a specific value here?  Return a real error please.
Or return 0 if that's not allowed.

v
> +
> +	return ret;
> +}
> +
>  static int fastrpc_device_open(struct inode *inode, struct file *filp)
>  {
>  	struct fastrpc_channel_ctx *cctx;
> @@ -1582,6 +1605,12 @@ static int fastrpc_device_open(struct inode *inode, struct file *filp)
>  	fl->cctx = cctx;
>  	fl->is_secure_dev = fdevice->secure;
>  
> +	fl->dsp_pgid = fastrpc_pgid_alloc(cctx);
> +	if (fl->dsp_pgid == -1) {
> +		dev_dbg(&cctx->rpdev->dev, "too many fastrpc clients, max %u allowed\n", MAX_DSP_PD);
> +		return -EUSERS;

Why -EUSERS?

And you obviously did not test this as you just leaked memory :(

thanks,

greg k-h