netdev - Re: [PATCH net-next 2/3] net: mvmdio: Avoid excessive sleeps in polled mode

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Message-ID: <20231202124508.3ac34fcf@kernel.org>
Date: Sat, 2 Dec 2023 12:45:08 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: Tobias Waldekranz <tobias@...dekranz.com>
Cc: davem@...emloft.net, andrew@...n.ch, gregory.clement@...tlin.com,
 sebastian.hesselbarth@...il.com, robh+dt@...nel.org,
 krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
 netdev@...r.kernel.org
Subject: Re: [PATCH net-next 2/3] net: mvmdio: Avoid excessive sleeps in
 polled mode

On Fri,  1 Dec 2023 18:35:44 +0100 Tobias Waldekranz wrote:
> @@ -94,23 +88,24 @@ static int orion_mdio_wait_ready(const struct orion_mdio_ops *ops,
>  				 struct mii_bus *bus)
>  {
>  	struct orion_mdio_dev *dev = bus->priv;
> -	unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
> -	unsigned long end = jiffies + timeout;
> -	int timedout = 0;
> +	unsigned long end, timeout;
> +	int done, timedout;
>  
> -	while (1) {
> -	        if (ops->is_done(dev))
> +	if (dev->err_interrupt <= 0) {
> +		if (!read_poll_timeout_atomic(ops->is_done, done, done, 2,
> +					      MVMDIO_SMI_TIMEOUT, false, dev))
>  			return 0;
> -	        else if (timedout)
> -			break;
> -
> -	        if (dev->err_interrupt <= 0) {
> -			usleep_range(ops->poll_interval_min,
> -				     ops->poll_interval_max);
> +	} else {
> +		timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
> +		end = jiffies + timeout;
> +		timedout = 0;
> +
> +		while (1) {
> +			if (ops->is_done(dev))
> +				return 0;
> +			else if (timedout)
> +				break;
>  
> -			if (time_is_before_jiffies(end))
> -				++timedout;
> -	        } else {
>  			/* wait_event_timeout does not guarantee a delay of at
>  			 * least one whole jiffie, so timeout must be no less
>  			 * than two.

drivers/net/ethernet/marvell/mvmdio.c:91:16: warning: variable 'end' set but not used [-Wunused-but-set-variable]
   91 |         unsigned long end, timeout;
      |                       ^
-- 
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