Re: [PATCH 06/14] iwlwifi: rework iwl_scan_cancel_timeout

["Guy, Wey-Yi" <wey-yi.w.guy@intel.com>]

On Fri, 2010-09-10 at 07:26 -0700, Stanislaw Gruszka wrote:
> Since on timeout version of iwl_scan_cancel procedure we can sleep,
> do not have to schedule abort_scan work to begin and perform scanning,
> can do this directly. Also now, as we do not queue abort_scan from
> restart work anymore, we can queue abort_scan to priv->workqueue.
> 
> Don't drop mutex when waiting for scan complete. Use STATUS_HW_SCAN bit
> to check if scanning is currently pending, because STATUS_SCANNING will
> be cleared only with priv->mutex taken.
> 
> Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Wey-Yi W Guy <wey-yi.w.guy@intel.com>
> ---
>  drivers/net/wireless/iwlwifi/iwl-scan.c |   25 ++++++++++++-------------
>  1 files changed, 12 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/net/wireless/iwlwifi/iwl-scan.c b/drivers/net/wireless/iwlwifi/iwl-scan.c
> index dbb07e8..6d02f41 100644
> --- a/drivers/net/wireless/iwlwifi/iwl-scan.c
> +++ b/drivers/net/wireless/iwlwifi/iwl-scan.c
> @@ -126,7 +126,7 @@ static void iwl_do_scan_abort(struct iwl_priv *priv)
>  int iwl_scan_cancel(struct iwl_priv *priv)
>  {
>  	IWL_DEBUG_SCAN(priv, "Queuing abort scan\n");
> -	schedule_work(&priv->abort_scan);
> +	queue_work(priv->workqueue, &priv->abort_scan);
>  	return 0;
>  }
>  EXPORT_SYMBOL(iwl_scan_cancel);
> @@ -135,25 +135,24 @@ EXPORT_SYMBOL(iwl_scan_cancel);
>   * iwl_scan_cancel_timeout - Cancel any currently executing HW scan
>   * @ms: amount of time to wait (in milliseconds) for scan to abort
>   *
> - * NOTE: priv->mutex must be held before calling this function
>   */
>  int iwl_scan_cancel_timeout(struct iwl_priv *priv, unsigned long ms)
>  {
> -	unsigned long now = jiffies;
> -	int ret;
> +	unsigned long timeout = jiffies + msecs_to_jiffies(ms);
> +
> +	lockdep_assert_held(&priv->mutex);
>  
> -	ret = iwl_scan_cancel(priv);
> -	if (ret && ms) {
> -		mutex_unlock(&priv->mutex);
> -		while (!time_after(jiffies, now + msecs_to_jiffies(ms)) &&
> -				test_bit(STATUS_SCANNING, &priv->status))
> -			msleep(1);
> -		mutex_lock(&priv->mutex);
> +	IWL_DEBUG_SCAN(priv, "Scan cancel timeout\n");
>  
> -		return test_bit(STATUS_SCANNING, &priv->status);
> +	iwl_do_scan_abort(priv);
> +
> +	while (time_before_eq(jiffies, timeout)) {
> +		if (!test_bit(STATUS_SCAN_HW, &priv->status))
> +			break;
> +		msleep(20);
>  	}
>  
> -	return ret;
> +	return test_bit(STATUS_SCAN_HW, &priv->status);
>  }
>  EXPORT_SYMBOL(iwl_scan_cancel_timeout);
>