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Commit 1974cc20 authored by Ben Hutchings's avatar Ben Hutchings Committed by David S. Miller
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sfc: Replace stats_enabled flag with a disable count 



Currently we use a spin-lock to serialise statistics fetches and also
to inhibit them for short periods of time, plus a flag to
enable/disable statistics fetches for longer periods of time, during
online reset.  This was apparently insufficient to deal with the several
reasons for stats being disabled.

Signed-off-by: default avatarBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent af4ad9bc

drivers/net/sfc/efx.c

+22 −11
Original line number Diff line number Diff line
@@ -685,7 +685,7 @@ static int efx_init_port(struct efx_nic *efx) 
	efx->mac_op->reconfigure(efx);



	efx->port_initialized = true;

	efx->stats_enabled = true;

	efx_stats_enable(efx);

	return 0;



fail:
@@ -734,6 +734,7 @@ static void efx_fini_port(struct efx_nic *efx) 
	if (!efx->port_initialized)

		return;



	efx_stats_disable(efx);

	efx->phy_op->fini(efx);

	efx->port_initialized = false;
@@ -1360,6 +1361,20 @@ static int efx_net_stop(struct net_device *net_dev) 
	return 0;

}



void efx_stats_disable(struct efx_nic *efx)

{

	spin_lock(&efx->stats_lock);

	++efx->stats_disable_count;

	spin_unlock(&efx->stats_lock);

}



void efx_stats_enable(struct efx_nic *efx)

{

	spin_lock(&efx->stats_lock);

	--efx->stats_disable_count;

	spin_unlock(&efx->stats_lock);

}



/* Context: process, dev_base_lock or RTNL held, non-blocking. */

static struct net_device_stats *efx_net_stats(struct net_device *net_dev)

{
@@ -1368,12 +1383,12 @@ static struct net_device_stats *efx_net_stats(struct net_device *net_dev) 
	struct net_device_stats *stats = &net_dev->stats;



	/* Update stats if possible, but do not wait if another thread

	 * is updating them (or resetting the NIC); slightly stale

	 * stats are acceptable.

	 * is updating them or if MAC stats fetches are temporarily

	 * disabled; slightly stale stats are acceptable.

	 */

	if (!spin_trylock(&efx->stats_lock))

		return stats;

	if (efx->stats_enabled) {

	if (!efx->stats_disable_count) {

		efx->mac_op->update_stats(efx);

		falcon_update_nic_stats(efx);

	}
@@ -1626,12 +1641,7 @@ void efx_reset_down(struct efx_nic *efx, enum reset_type method, 
{

	EFX_ASSERT_RESET_SERIALISED(efx);



	/* The net_dev->get_stats handler is quite slow, and will fail

	 * if a fetch is pending over reset. Serialise against it. */

	spin_lock(&efx->stats_lock);

	efx->stats_enabled = false;

	spin_unlock(&efx->stats_lock);



	efx_stats_disable(efx);

	efx_stop_all(efx);

	mutex_lock(&efx->mac_lock);

	mutex_lock(&efx->spi_lock);
@@ -1682,7 +1692,7 @@ int efx_reset_up(struct efx_nic *efx, enum reset_type method, 


	if (ok) {

		efx_start_all(efx);

		efx->stats_enabled = true;

		efx_stats_enable(efx);

	}

	return rc;

}
@@ -1888,6 +1898,7 @@ static int efx_init_struct(struct efx_nic *efx, struct efx_nic_type *type, 
	efx->rx_checksum_enabled = true;

	spin_lock_init(&efx->netif_stop_lock);

	spin_lock_init(&efx->stats_lock);

	efx->stats_disable_count = 1;

	mutex_init(&efx->mac_lock);

	efx->mac_op = &efx_dummy_mac_operations;

	efx->phy_op = &efx_dummy_phy_operations;

drivers/net/sfc/efx.h

+2 −0
Original line number Diff line number Diff line
@@ -36,6 +36,8 @@ extern void efx_process_channel_now(struct efx_channel *channel); 
extern void efx_flush_queues(struct efx_nic *efx);



/* Ports */

extern void efx_stats_disable(struct efx_nic *efx);

extern void efx_stats_enable(struct efx_nic *efx);

extern void efx_reconfigure_port(struct efx_nic *efx);

extern void __efx_reconfigure_port(struct efx_nic *efx);

drivers/net/sfc/falcon.c

+11 −4
Original line number Diff line number Diff line
@@ -1883,7 +1883,7 @@ static int falcon_reset_macs(struct efx_nic *efx) 


	/* MAC stats will fail whilst the TX fifo is draining. Serialise

	 * the drain sequence with the statistics fetch */

	spin_lock(&efx->stats_lock);

	efx_stats_disable(efx);



	falcon_read(efx, &reg, MAC0_CTRL_REG_KER);

	EFX_SET_OWORD_FIELD(reg, TXFIFO_DRAIN_EN_B0, 1);
@@ -1913,7 +1913,7 @@ static int falcon_reset_macs(struct efx_nic *efx) 
		udelay(10);

	}



	spin_unlock(&efx->stats_lock);

	efx_stats_enable(efx);



	/* If we've reset the EM block and the link is up, then

	 * we'll have to kick the XAUI link so the PHY can recover */
@@ -2273,6 +2273,10 @@ int falcon_switch_mac(struct efx_nic *efx) 
	struct efx_mac_operations *old_mac_op = efx->mac_op;

	efx_oword_t nic_stat;

	unsigned strap_val;

	int rc = 0;



	/* Don't try to fetch MAC stats while we're switching MACs */

	efx_stats_disable(efx);



	/* Internal loopbacks override the phy speed setting */

	if (efx->loopback_mode == LOOPBACK_GMAC) {
@@ -2302,13 +2306,16 @@ int falcon_switch_mac(struct efx_nic *efx) 
	}



	if (old_mac_op == efx->mac_op)

		return 0;

		goto out;



	EFX_LOG(efx, "selected %cMAC\n", EFX_IS10G(efx) ? 'X' : 'G');

	/* Not all macs support a mac-level link state */

	efx->mac_up = true;



	return falcon_reset_macs(efx);

	rc = falcon_reset_macs(efx);

out:

	efx_stats_enable(efx);

	return rc;

}



/* This call is responsible for hooking in the MAC and PHY operations */

drivers/net/sfc/net_driver.h

+2 −3
Original line number Diff line number Diff line
@@ -754,8 +754,7 @@ union efx_multicast_hash { 
 *	&struct net_device_stats.

 * @stats_buffer: DMA buffer for statistics

 * @stats_lock: Statistics update lock. Serialises statistics fetches

 * @stats_enabled: Temporarily disable statistics fetches.

 *	Serialised by @stats_lock

 * @stats_disable_count: Nest count for disabling statistics fetches

 * @mac_op: MAC interface

 * @mac_address: Permanent MAC address

 * @phy_type: PHY type
@@ -837,7 +836,7 @@ struct efx_nic { 
	struct efx_mac_stats mac_stats;

	struct efx_buffer stats_buffer;

	spinlock_t stats_lock;

	bool stats_enabled;

	unsigned int stats_disable_count;



	struct efx_mac_operations *mac_op;

	unsigned char mac_address[ETH_ALEN];

drivers/net/sfc/sfe4001.c

+14 −1
Original line number Diff line number Diff line
@@ -235,12 +235,18 @@ static ssize_t set_phy_flash_cfg(struct device *dev, 
	} else if (efx->state != STATE_RUNNING || netif_running(efx->net_dev)) {

		err = -EBUSY;

	} else {

		/* Reset the PHY, reconfigure the MAC and enable/disable

		 * MAC stats accordingly. */

		efx->phy_mode = new_mode;

		if (new_mode & PHY_MODE_SPECIAL)

			efx_stats_disable(efx);

		if (efx->board_info.type == EFX_BOARD_SFE4001)

			err = sfe4001_poweron(efx);

		else

			err = sfn4111t_reset(efx);

		efx_reconfigure_port(efx);

		if (!(new_mode & PHY_MODE_SPECIAL))

			efx_stats_enable(efx);

	}

	rtnl_unlock();
@@ -329,6 +335,11 @@ int sfe4001_init(struct efx_nic *efx) 
	efx->board_info.monitor = sfe4001_check_hw;

	efx->board_info.fini = sfe4001_fini;



	if (efx->phy_mode & PHY_MODE_SPECIAL) {

		/* PHY won't generate a 156.25 MHz clock and MAC stats fetch

		 * will fail. */

		efx_stats_disable(efx);

	}

	rc = sfe4001_poweron(efx);

	if (rc)

		goto fail_ioexp;
@@ -405,8 +416,10 @@ int sfn4111t_init(struct efx_nic *efx) 
	if (rc)

		goto fail_hwmon;



	if (efx->phy_mode & PHY_MODE_SPECIAL)

	if (efx->phy_mode & PHY_MODE_SPECIAL) {

		efx_stats_disable(efx);

		sfn4111t_reset(efx);

	}



	return 0;