Re: [PATCH 1/1] s390/ism: fix concurrency management in ism_cmd()

[Alexander Gordeev <agordeev@linux.ibm.com>]

On Sun, Jul 20, 2025 at 11:11:09PM +0200, Halil Pasic wrote:

Hi Halil,

...
> @@ -129,7 +129,9 @@ static int ism_cmd(struct ism_dev *ism, void *cmd)
>  {
>  	struct ism_req_hdr *req = cmd;
>  	struct ism_resp_hdr *resp = cmd;
> +	unsigned long flags;
>  
> +	spin_lock_irqsave(&ism->cmd_lock, flags);

I only found smcd_handle_irq() scheduling a tasklet, but no commands issued.
Do we really need disable interrupts?

>  	__ism_write_cmd(ism, req + 1, sizeof(*req), req->len - sizeof(*req));
>  	__ism_write_cmd(ism, req, 0, sizeof(*req));
>  
> @@ -143,6 +145,7 @@ static int ism_cmd(struct ism_dev *ism, void *cmd)
>  	}
>  	__ism_read_cmd(ism, resp + 1, sizeof(*resp), resp->len - sizeof(*resp));
>  out:
> +	spin_unlock_irqrestore(&ism->cmd_lock, flags);
>  	return resp->ret;
>  }
>  
...

Thanks!