Re: [PATCH 2/2] cxl/mbox: return appropriate error in cxl_payload_from_user_allowed()

[Jonathan Cameron <jonathan.cameron@huawei.com>]

On Thu, 19 Feb 2026 16:16:18 -0800
Davidlohr Bueso <dave@stgolabs.net> wrote:

> Make cxl_payload_from_user_allowed() return int such that the it can
> distinguish between different errors. The payload size failure is not
> well represented by EBUSY (exclusive access by the kernel).
> 
> Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Hi Davidlohr,

If you are going to sneak in a fix to quotation style, then I'd like to see
it mentioned in the commit message.

Anyhow either way
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>

> +static int cxl_payload_from_user_allowed(u16 opcode, void *payload_in,
> +					 size_t in_size)
>  {
>  	switch (opcode) {
>  	case CXL_MBOX_OP_SET_PARTITION_INFO: {
>  		struct cxl_mbox_set_partition_info *pi = payload_in;
>  
>  		if (in_size < sizeof(*pi))
> -			return false;
> +			return -EINVAL;
>  		if (pi->flags & CXL_SET_PARTITION_IMMEDIATE_FLAG)
> -			return false;
> +			return -EBUSY;
>  		break;
>  	}
>  	case CXL_MBOX_OP_CLEAR_LOG: {
>  		const uuid_t *uuid = (uuid_t *)payload_in;
>  
>  		if (in_size < sizeof(uuid_t))
> -			return false;
> +			return -EINVAL;
>  		/*
> -		 * Restrict the ‘Clear log’ action to only apply to
> +		 * Restrict the 'Clear log' action to only apply to
Unrelated change. I don't mind it but should at least be mentioned.
Maybe Dave can add something to the commit description when picking this up.


>  		 * Vendor debug logs.
>  		 */
> -		return uuid_equal(uuid, &DEFINE_CXL_VENDOR_DEBUG_UUID);
> +		if (!uuid_equal(uuid, &DEFINE_CXL_VENDOR_DEBUG_UUID))