[V2,11/36] net: ionic: Replace in_interrupt() usage.

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

The in_interrupt() usage in this driver tries to figure out which context
may sleep and which context may not sleep. in_interrupt() is not really
suitable as it misses both preemption disabled and interrupt disabled
invocations from task context.

Conditionals like that in driver code are frowned upon in general because
invocations of functions from invalid contexts might not be detected
as the conditional papers over it.

ionic_lif_addr() and _ionoc_lif_rx_mode() can be called from:

 1) ->ndo_set_rx_mode() which is under netif_addr_lock_bh()) so it must not
    sleep.

 2) Init and setup functions which are in fully preemptible task context.

ionic_link_status_check_request() has two call paths:

 1) NAPI which obviously cannot sleep

 2) Setup which is again fully preemptible task context

Add arguments which convey the execution context to the affected functions
and let the callers provide the context instead of letting the functions
deduce it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V2: Treat _ionoc_lif_rx_mode() correclty (Shannon)
---
 drivers/net/ethernet/pensando/ionic/ionic_dev.c |    2 
 drivers/net/ethernet/pensando/ionic/ionic_lif.c |   64 ++++++++++++++++--------
 drivers/net/ethernet/pensando/ionic/ionic_lif.h |    2 
 3 files changed, 47 insertions(+), 21 deletions(-)

On 9/29/20 1:25 PM, Thomas Gleixner wrote:
> From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
>
> The in_interrupt() usage in this driver tries to figure out which context
> may sleep and which context may not sleep. in_interrupt() is not really
> suitable as it misses both preemption disabled and interrupt disabled
> invocations from task context.
>
> Conditionals like that in driver code are frowned upon in general because
> invocations of functions from invalid contexts might not be detected
> as the conditional papers over it.
>
> ionic_lif_addr() and _ionoc_lif_rx_mode() can be called from:
>
>   1) ->ndo_set_rx_mode() which is under netif_addr_lock_bh()) so it must not
>      sleep.
>
>   2) Init and setup functions which are in fully preemptible task context.
>
> ionic_link_status_check_request() has two call paths:
>
>   1) NAPI which obviously cannot sleep
>
>   2) Setup which is again fully preemptible task context
>
> Add arguments which convey the execution context to the affected functions
> and let the callers provide the context instead of letting the functions
> deduce it.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> V2: Treat _ionoc_lif_rx_mode() correclty (Shannon)

Is it fair to poke at the comments?
s/ionoc/ionic/
s/correclty/correctly/

> ---
>   drivers/net/ethernet/pensando/ionic/ionic_dev.c |    2
>   drivers/net/ethernet/pensando/ionic/ionic_lif.c |   64 ++++++++++++++++--------
>   drivers/net/ethernet/pensando/ionic/ionic_lif.h |    2
>   3 files changed, 47 insertions(+), 21 deletions(-)
>
> --- a/drivers/net/ethernet/pensando/ionic/ionic_dev.c
> +++ b/drivers/net/ethernet/pensando/ionic/ionic_dev.c
> @@ -22,7 +22,7 @@ static void ionic_watchdog_cb(struct tim
>   	hb = ionic_heartbeat_check(ionic);
>   
>   	if (hb >= 0 && ionic->lif)
> -		ionic_link_status_check_request(ionic->lif);
> +		ionic_link_status_check_request(ionic->lif, false);
>   }
>   
>   void ionic_init_devinfo(struct ionic *ionic)
> --- a/drivers/net/ethernet/pensando/ionic/ionic_lif.c
> +++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
> @@ -151,7 +151,7 @@ static void ionic_link_status_check(stru
>   	clear_bit(IONIC_LIF_F_LINK_CHECK_REQUESTED, lif->state);
>   }
>   
> -void ionic_link_status_check_request(struct ionic_lif *lif)
> +void ionic_link_status_check_request(struct ionic_lif *lif, bool can_sleep)
>   {
>   	struct ionic_deferred_work *work;
>   
> @@ -159,7 +159,7 @@ void ionic_link_status_check_request(str
>   	if (test_and_set_bit(IONIC_LIF_F_LINK_CHECK_REQUESTED, lif->state))
>   		return;
>   
> -	if (in_interrupt()) {
> +	if (!can_sleep) {
>   		work = kzalloc(sizeof(*work), GFP_ATOMIC);
>   		if (!work)
>   			return;
> @@ -798,7 +798,7 @@ static bool ionic_notifyq_service(struct
>   
>   	switch (le16_to_cpu(comp->event.ecode)) {
>   	case IONIC_EVENT_LINK_CHANGE:
> -		ionic_link_status_check_request(lif);
> +		ionic_link_status_check_request(lif, false);
>   		break;
>   	case IONIC_EVENT_RESET:
>   		work = kzalloc(sizeof(*work), GFP_ATOMIC);
> @@ -981,7 +981,8 @@ static int ionic_lif_addr_del(struct ion
>   	return 0;
>   }
>   
> -static int ionic_lif_addr(struct ionic_lif *lif, const u8 *addr, bool add)
> +static int ionic_lif_addr(struct ionic_lif *lif, const u8 *addr, bool add,
> +			  bool can_sleep)
>   {
>   	struct ionic *ionic = lif->ionic;
>   	struct ionic_deferred_work *work;
> @@ -1010,7 +1011,7 @@ static int ionic_lif_addr(struct ionic_l
>   			lif->nucast--;
>   	}
>   
> -	if (in_interrupt()) {
> +	if (!can_sleep) {
>   		work = kzalloc(sizeof(*work), GFP_ATOMIC);
>   		if (!work) {
>   			netdev_err(lif->netdev, "%s OOM\n", __func__);
> @@ -1036,12 +1037,22 @@ static int ionic_lif_addr(struct ionic_l
>   
>   static int ionic_addr_add(struct net_device *netdev, const u8 *addr)
>   {
> -	return ionic_lif_addr(netdev_priv(netdev), addr, true);
> +	return ionic_lif_addr(netdev_priv(netdev), addr, true, true);
> +}
> +
> +static int ionic_ndo_addr_add(struct net_device *netdev, const u8 *addr)
> +{
> +	return ionic_lif_addr(netdev_priv(netdev), addr, true, false);
>   }
>   
>   static int ionic_addr_del(struct net_device *netdev, const u8 *addr)
>   {
> -	return ionic_lif_addr(netdev_priv(netdev), addr, false);
> +	return ionic_lif_addr(netdev_priv(netdev), addr, false, true);
> +}
> +
> +static int ionic_ndo_addr_del(struct net_device *netdev, const u8 *addr)
> +{
> +	return ionic_lif_addr(netdev_priv(netdev), addr, false, false);
>   }

These changes are reasonable, tho' I'm not fond of parameter lists of 
"true" and "false" with no context.  I'd prefer to have some constants like
#define can_sleep true
so the code can be a little more readable.

Yes, I know we have this problem already in the call to 
ionic_lif_addr(), which I'm annoyed with but haven't addressed yet.

So, if you want to deal with this now, fine, otherwise I'll take care of 
them both later.

Meanwhile,

Acked-by: Shannon Nelson <snelson@pensando.io>




>   
>   static void ionic_lif_rx_mode(struct ionic_lif *lif, unsigned int rx_mode)
> @@ -1081,11 +1092,12 @@ static void ionic_lif_rx_mode(struct ion
>   		lif->rx_mode = rx_mode;
>   }
>   
> -static void _ionic_lif_rx_mode(struct ionic_lif *lif, unsigned int rx_mode)
> +static void _ionic_lif_rx_mode(struct ionic_lif *lif, unsigned int rx_mode,
> +			       bool from_ndo)
>   {
>   	struct ionic_deferred_work *work;
>   
> -	if (in_interrupt()) {
> +	if (from_ndo) {
>   		work = kzalloc(sizeof(*work), GFP_ATOMIC);
>   		if (!work) {
>   			netdev_err(lif->netdev, "%s OOM\n", __func__);
> @@ -1100,7 +1112,16 @@ static void _ionic_lif_rx_mode(struct io
>   	}
>   }
>   
> -static void ionic_set_rx_mode(struct net_device *netdev)
> +static void ionic_dev_uc_sync(struct net_device *netdev, bool from_ndo)
> +{
> +	if (from_ndo)
> +		__dev_uc_sync(netdev, ionic_ndo_addr_add, ionic_ndo_addr_del);
> +	else
> +		__dev_uc_sync(netdev, ionic_addr_add, ionic_addr_del);
> +
> +}
> +
> +static void ionic_set_rx_mode(struct net_device *netdev, bool from_ndo)
>   {
>   	struct ionic_lif *lif = netdev_priv(netdev);
>   	struct ionic_identity *ident;
> @@ -1122,7 +1143,7 @@ static void ionic_set_rx_mode(struct net
>   	 *       we remove our overflow flag and check the netdev flags
>   	 *       to see if we can disable NIC PROMISC
>   	 */
> -	__dev_uc_sync(netdev, ionic_addr_add, ionic_addr_del);
> +	ionic_dev_uc_sync(netdev, from_ndo);
>   	nfilters = le32_to_cpu(ident->lif.eth.max_ucast_filters);
>   	if (netdev_uc_count(netdev) + 1 > nfilters) {
>   		rx_mode |= IONIC_RX_MODE_F_PROMISC;
> @@ -1134,7 +1155,7 @@ static void ionic_set_rx_mode(struct net
>   	}
>   
>   	/* same for multicast */
> -	__dev_mc_sync(netdev, ionic_addr_add, ionic_addr_del);
> +	ionic_dev_uc_sync(netdev, from_ndo);
>   	nfilters = le32_to_cpu(ident->lif.eth.max_mcast_filters);
>   	if (netdev_mc_count(netdev) > nfilters) {
>   		rx_mode |= IONIC_RX_MODE_F_ALLMULTI;
> @@ -1146,7 +1167,12 @@ static void ionic_set_rx_mode(struct net
>   	}
>   
>   	if (lif->rx_mode != rx_mode)
> -		_ionic_lif_rx_mode(lif, rx_mode);
> +		_ionic_lif_rx_mode(lif, rx_mode, from_ndo);
> +}
> +
> +static void ionic_ndo_set_rx_mode(struct net_device *netdev)
> +{
> +	ionic_set_rx_mode(netdev, true);
>   }
>   
>   static __le64 ionic_netdev_features_to_nic(netdev_features_t features)
> @@ -1391,7 +1417,7 @@ static int ionic_start_queues_reconfig(s
>   	 */
>   	err = ionic_txrx_init(lif);
>   	mutex_unlock(&lif->queue_lock);
> -	ionic_link_status_check_request(lif);
> +	ionic_link_status_check_request(lif, true);
>   	netif_device_attach(lif->netdev);
>   
>   	return err;
> @@ -1720,7 +1746,7 @@ static int ionic_txrx_init(struct ionic_
>   	if (lif->netdev->features & NETIF_F_RXHASH)
>   		ionic_lif_rss_init(lif);
>   
> -	ionic_set_rx_mode(lif->netdev);
> +	ionic_set_rx_mode(lif->netdev, false);
>   
>   	return 0;
>   
> @@ -2093,7 +2119,7 @@ static const struct net_device_ops ionic
>   	.ndo_stop               = ionic_stop,
>   	.ndo_start_xmit		= ionic_start_xmit,
>   	.ndo_get_stats64	= ionic_get_stats64,
> -	.ndo_set_rx_mode	= ionic_set_rx_mode,
> +	.ndo_set_rx_mode	= ionic_ndo_set_rx_mode,
>   	.ndo_set_features	= ionic_set_features,
>   	.ndo_set_mac_address	= ionic_set_mac_address,
>   	.ndo_validate_addr	= eth_validate_addr,
> @@ -2521,7 +2547,7 @@ static void ionic_lif_handle_fw_up(struc
>   	}
>   
>   	clear_bit(IONIC_LIF_F_FW_RESET, lif->state);
> -	ionic_link_status_check_request(lif);
> +	ionic_link_status_check_request(lif, true);
>   	netif_device_attach(lif->netdev);
>   	dev_info(ionic->dev, "FW Up: LIFs restarted\n");
>   
> @@ -2713,7 +2739,7 @@ static int ionic_station_set(struct ioni
>   		 */
>   		if (!ether_addr_equal(ctx.comp.lif_getattr.mac,
>   				      netdev->dev_addr))
> -			ionic_lif_addr(lif, netdev->dev_addr, true);
> +			ionic_lif_addr(lif, netdev->dev_addr, true, true);
>   	} else {
>   		/* Update the netdev mac with the device's mac */
>   		memcpy(addr.sa_data, ctx.comp.lif_getattr.mac, netdev->addr_len);
> @@ -2730,7 +2756,7 @@ static int ionic_station_set(struct ioni
>   
>   	netdev_dbg(lif->netdev, "adding station MAC addr %pM\n",
>   		   netdev->dev_addr);
> -	ionic_lif_addr(lif, netdev->dev_addr, true);
> +	ionic_lif_addr(lif, netdev->dev_addr, true, true);
>   
>   	return 0;
>   }
> --- a/drivers/net/ethernet/pensando/ionic/ionic_lif.h
> +++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.h
> @@ -245,7 +245,7 @@ static inline u32 ionic_coal_usec_to_hw(
>   
>   typedef void (*ionic_reset_cb)(struct ionic_lif *lif, void *arg);
>   
> -void ionic_link_status_check_request(struct ionic_lif *lif);
> +void ionic_link_status_check_request(struct ionic_lif *lif, bool can_sleep);
>   void ionic_get_stats64(struct net_device *netdev,
>   		       struct rtnl_link_stats64 *ns);
>   void ionic_lif_deferred_enqueue(struct ionic_deferred *def,
>