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Message-ID: <20090130040007.GM15266@solarflare.com>
Date: Fri, 30 Jan 2009 04:00:07 +0000
From: Ben Hutchings <bhutchings@...arflare.com>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org, linux-net-drivers@...arflare.com
Subject: [PATCH 11/11] 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: Ben Hutchings <bhutchings@...arflare.com>
---
drivers/net/sfc/efx.c | 33 ++++++++++++++++++++++-----------
drivers/net/sfc/efx.h | 2 ++
drivers/net/sfc/falcon.c | 15 +++++++++++----
drivers/net/sfc/net_driver.h | 5 ++---
drivers/net/sfc/sfe4001.c | 15 ++++++++++++++-
drivers/net/sfc/tenxpress.c | 12 ++++++------
6 files changed, 57 insertions(+), 25 deletions(-)
diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index b0e5308..ab0e09b 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -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;
diff --git a/drivers/net/sfc/efx.h b/drivers/net/sfc/efx.h
index ac20158..55d0f13 100644
--- a/drivers/net/sfc/efx.h
+++ b/drivers/net/sfc/efx.h
@@ -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);
diff --git a/drivers/net/sfc/falcon.c b/drivers/net/sfc/falcon.c
index d9412f8..d5378e6 100644
--- a/drivers/net/sfc/falcon.c
+++ b/drivers/net/sfc/falcon.c
@@ -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, ®, 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 */
diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index 8eb411a..e019ad1 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -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];
diff --git a/drivers/net/sfc/sfe4001.c b/drivers/net/sfc/sfe4001.c
index 853057e..cb25ae5 100644
--- a/drivers/net/sfc/sfe4001.c
+++ b/drivers/net/sfc/sfe4001.c
@@ -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;
diff --git a/drivers/net/sfc/tenxpress.c b/drivers/net/sfc/tenxpress.c
index 412d209..f0efd24 100644
--- a/drivers/net/sfc/tenxpress.c
+++ b/drivers/net/sfc/tenxpress.c
@@ -370,8 +370,8 @@ static int tenxpress_special_reset(struct efx_nic *efx)
/* The XGMAC clock is driven from the SFC7101/SFT9001 312MHz clock, so
* a special software reset can glitch the XGMAC sufficiently for stats
- * requests to fail. Since we don't often special_reset, just lock. */
- spin_lock(&efx->stats_lock);
+ * requests to fail. */
+ efx_stats_disable(efx);
/* Initiate reset */
reg = mdio_clause45_read(efx, efx->mii.phy_id,
@@ -386,17 +386,17 @@ static int tenxpress_special_reset(struct efx_nic *efx)
rc = mdio_clause45_wait_reset_mmds(efx,
TENXPRESS_REQUIRED_DEVS);
if (rc < 0)
- goto unlock;
+ goto out;
/* Try and reconfigure the device */
rc = tenxpress_init(efx);
if (rc < 0)
- goto unlock;
+ goto out;
/* Wait for the XGXS state machine to churn */
mdelay(10);
-unlock:
- spin_unlock(&efx->stats_lock);
+out:
+ efx_stats_enable(efx);
return rc;
}
--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
--
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