Re: [PATCH net-next] liquidio: Remove unneeded cast from memory allocation

[Joe Perches]

On Fri, 2020-07-24 at 21:00 +0800, Wang Hai wrote:
> Remove casting the values returned by memory allocation function.
> 
> Coccinelle emits WARNING:
> 
> ./drivers/net/ethernet/cavium/liquidio/octeon_device.c:1155:14-36: WARNING:
>  casting value returned by memory allocation function to (struct octeon_dispatch *) is useless.
[]
> diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_device.c b/drivers/net/ethernet/cavium/liquidio/octeon_device.c
[]
> @@ -1152,8 +1152,7 @@ octeon_register_dispatch_fn(struct octeon_device *oct,
>  
>  		dev_dbg(&oct->pci_dev->dev,
>  			"Adding opcode to dispatch list linked list\n");
> -		dispatch = (struct octeon_dispatch *)
> -			   vmalloc(sizeof(struct octeon_dispatch));
> +		dispatch = vmalloc(sizeof(struct octeon_dispatch));

More the question is why this is vmalloc at all
as the structure size is very small.

Likely this should just be kmalloc.

drivers/net/ethernet/cavium/liquidio/octeon_device.h:struct octeon_dispatch {
drivers/net/ethernet/cavium/liquidio/octeon_device.h-   /** List head for this entry */
drivers/net/ethernet/cavium/liquidio/octeon_device.h-   struct list_head list;
drivers/net/ethernet/cavium/liquidio/octeon_device.h-
drivers/net/ethernet/cavium/liquidio/octeon_device.h-   /** The opcode for which the dispatch function & arg should be used */
drivers/net/ethernet/cavium/liquidio/octeon_device.h-   u16 opcode;
drivers/net/ethernet/cavium/liquidio/octeon_device.h-
drivers/net/ethernet/cavium/liquidio/octeon_device.h-   /** The function to be called for a packet received by the driver */
drivers/net/ethernet/cavium/liquidio/octeon_device.h-   octeon_dispatch_fn_t dispatch_fn;
drivers/net/ethernet/cavium/liquidio/octeon_device.h-
drivers/net/ethernet/cavium/liquidio/octeon_device.h-   /* The application specified argument to be passed to the above
drivers/net/ethernet/cavium/liquidio/octeon_device.h-    * function along with the received packet
drivers/net/ethernet/cavium/liquidio/octeon_device.h-    */
drivers/net/ethernet/cavium/liquidio/octeon_device.h-   void *arg;
drivers/net/ethernet/cavium/liquidio/octeon_device.h-}

>  		if (!dispatch) {
>  			dev_err(&oct->pci_dev->dev,
>  				"No memory to add dispatch function\n");

And this dev_err is unnecessary.