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Message-ID: <1310606206.2756.25.camel@bwh-desktop>
Date: Thu, 14 Jul 2011 02:16:46 +0100
From: Ben Hutchings <bhutchings@...arflare.com>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org, linux-net-drivers@...arflare.com
Subject: [PATCH net-next-2.6 2/7] sfc: Allow resets to be upgraded; use
atomic ops for safety
Currently an attempt to schedule any reset is ignored if a reset
is already pending. This ignores the relative scopes - if the
requested reset is greater in scope then the scheduled reset should
be upgraded accordingly.
There are also some race conditions which could lead to a reset
request being lost. Deal with them by using atomic operations on a
bitmask. This also makes tests on reset_pending easier to get right.
Signed-off-by: Ben Hutchings <bhutchings@...arflare.com>
---
drivers/net/sfc/efx.c | 38 +++++++++++++++++---------------------
drivers/net/sfc/enum.h | 3 ++-
drivers/net/sfc/falcon.c | 2 +-
drivers/net/sfc/net_driver.h | 4 ++--
4 files changed, 22 insertions(+), 25 deletions(-)
diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index c914729..9b4cfdb 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -229,8 +229,7 @@ static int efx_process_channel(struct efx_channel *channel, int budget)
struct efx_nic *efx = channel->efx;
int spent;
- if (unlikely(efx->reset_pending != RESET_TYPE_NONE ||
- !channel->enabled))
+ if (unlikely(efx->reset_pending || !channel->enabled))
return 0;
spent = efx_nic_process_eventq(channel, budget);
@@ -1461,7 +1460,7 @@ static void efx_start_all(struct efx_nic *efx)
* reset_pending [modified from an atomic context], we instead guarantee
* that efx_mcdi_mode_poll() isn't reverted erroneously */
efx_mcdi_mode_event(efx);
- if (efx->reset_pending != RESET_TYPE_NONE)
+ if (efx->reset_pending)
efx_mcdi_mode_poll(efx);
/* Start the hardware monitor if there is one. Otherwise (we're link
@@ -2118,8 +2117,10 @@ int efx_reset(struct efx_nic *efx, enum reset_type method)
goto out;
}
- /* Allow resets to be rescheduled. */
- efx->reset_pending = RESET_TYPE_NONE;
+ /* Clear flags for the scopes we covered. We assume the NIC and
+ * driver are now quiescent so that there is no race here.
+ */
+ efx->reset_pending &= -(1 << (method + 1));
/* Reinitialise bus-mastering, which may have been turned off before
* the reset was scheduled. This is still appropriate, even in the
@@ -2154,12 +2155,13 @@ out:
static void efx_reset_work(struct work_struct *data)
{
struct efx_nic *efx = container_of(data, struct efx_nic, reset_work);
+ unsigned long pending = ACCESS_ONCE(efx->reset_pending);
- if (efx->reset_pending == RESET_TYPE_NONE)
+ if (!pending)
return;
/* If we're not RUNNING then don't reset. Leave the reset_pending
- * flag set so that efx_pci_probe_main will be retried */
+ * flags set so that efx_pci_probe_main will be retried */
if (efx->state != STATE_RUNNING) {
netif_info(efx, drv, efx->net_dev,
"scheduled reset quenched. NIC not RUNNING\n");
@@ -2167,7 +2169,7 @@ static void efx_reset_work(struct work_struct *data)
}
rtnl_lock();
- (void)efx_reset(efx, efx->reset_pending);
+ (void)efx_reset(efx, fls(pending) - 1);
rtnl_unlock();
}
@@ -2175,12 +2177,6 @@ void efx_schedule_reset(struct efx_nic *efx, enum reset_type type)
{
enum reset_type method;
- if (efx->reset_pending != RESET_TYPE_NONE) {
- netif_info(efx, drv, efx->net_dev,
- "quenching already scheduled reset\n");
- return;
- }
-
switch (type) {
case RESET_TYPE_INVISIBLE:
case RESET_TYPE_ALL:
@@ -2208,7 +2204,7 @@ void efx_schedule_reset(struct efx_nic *efx, enum reset_type type)
netif_dbg(efx, drv, efx->net_dev, "scheduling %s reset\n",
RESET_TYPE(method));
- efx->reset_pending = method;
+ set_bit(method, &efx->reset_pending);
/* efx_process_channel() will no longer read events once a
* reset is scheduled. So switch back to poll'd MCDI completions. */
@@ -2288,7 +2284,6 @@ static int efx_init_struct(struct efx_nic *efx, const struct efx_nic_type *type,
efx->pci_dev = pci_dev;
efx->msg_enable = debug;
efx->state = STATE_INIT;
- efx->reset_pending = RESET_TYPE_NONE;
strlcpy(efx->name, pci_name(pci_dev), sizeof(efx->name));
efx->net_dev = net_dev;
@@ -2510,7 +2505,7 @@ static int __devinit efx_pci_probe(struct pci_dev *pci_dev,
cancel_work_sync(&efx->reset_work);
if (rc == 0) {
- if (efx->reset_pending != RESET_TYPE_NONE) {
+ if (efx->reset_pending) {
/* If there was a scheduled reset during
* probe, the NIC is probably hosed anyway */
efx_pci_remove_main(efx);
@@ -2521,11 +2516,12 @@ static int __devinit efx_pci_probe(struct pci_dev *pci_dev,
}
/* Retry if a recoverably reset event has been scheduled */
- if ((efx->reset_pending != RESET_TYPE_INVISIBLE) &&
- (efx->reset_pending != RESET_TYPE_ALL))
+ if (efx->reset_pending &
+ ~(1 << RESET_TYPE_INVISIBLE | 1 << RESET_TYPE_ALL) ||
+ !efx->reset_pending)
goto fail3;
- efx->reset_pending = RESET_TYPE_NONE;
+ efx->reset_pending = 0;
}
if (rc) {
@@ -2609,7 +2605,7 @@ static int efx_pm_poweroff(struct device *dev)
efx->type->fini(efx);
- efx->reset_pending = RESET_TYPE_NONE;
+ efx->reset_pending = 0;
pci_save_state(pci_dev);
return pci_set_power_state(pci_dev, PCI_D3hot);
diff --git a/drivers/net/sfc/enum.h b/drivers/net/sfc/enum.h
index 384cfe3..d725a8f 100644
--- a/drivers/net/sfc/enum.h
+++ b/drivers/net/sfc/enum.h
@@ -134,6 +134,8 @@ enum efx_loopback_mode {
* other valuesspecify reasons, which efx_schedule_reset() will choose
* a method for.
*
+ * Reset methods are numbered in order of increasing scope.
+ *
* @RESET_TYPE_INVISIBLE: don't reset the PHYs or interrupts
* @RESET_TYPE_ALL: reset everything but PCI core blocks
* @RESET_TYPE_WORLD: reset everything, save & restore PCI config
@@ -147,7 +149,6 @@ enum efx_loopback_mode {
* @RESET_TYPE_MC_FAILURE: MC reboot/assertion
*/
enum reset_type {
- RESET_TYPE_NONE = -1,
RESET_TYPE_INVISIBLE = 0,
RESET_TYPE_ALL = 1,
RESET_TYPE_WORLD = 2,
diff --git a/drivers/net/sfc/falcon.c b/drivers/net/sfc/falcon.c
index 60176e8..a4c7830 100644
--- a/drivers/net/sfc/falcon.c
+++ b/drivers/net/sfc/falcon.c
@@ -536,7 +536,7 @@ void falcon_reconfigure_mac_wrapper(struct efx_nic *efx)
efx_oword_t reg;
int link_speed, isolate;
- isolate = (efx->reset_pending != RESET_TYPE_NONE);
+ isolate = !!ACCESS_ONCE(efx->reset_pending);
switch (link_state->speed) {
case 10000: link_speed = 3; break;
diff --git a/drivers/net/sfc/net_driver.h b/drivers/net/sfc/net_driver.h
index e8d5f03..c422eb2 100644
--- a/drivers/net/sfc/net_driver.h
+++ b/drivers/net/sfc/net_driver.h
@@ -645,7 +645,7 @@ struct efx_filter_state;
* @irq_rx_moderation: IRQ moderation time for RX event queues
* @msg_enable: Log message enable flags
* @state: Device state flag. Serialised by the rtnl_lock.
- * @reset_pending: Pending reset method (normally RESET_TYPE_NONE)
+ * @reset_pending: Bitmask for pending resets
* @tx_queue: TX DMA queues
* @rx_queue: RX DMA queues
* @channel: Channels
@@ -728,7 +728,7 @@ struct efx_nic {
u32 msg_enable;
enum nic_state state;
- enum reset_type reset_pending;
+ unsigned long reset_pending;
struct efx_channel *channel[EFX_MAX_CHANNELS];
char channel_name[EFX_MAX_CHANNELS][IFNAMSIZ + 6];
--
1.7.4.4
--
Ben Hutchings, Senior Software Engineer, Solarflare
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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