From a7d529ae2158b5300e4aa16c21f1828bc864449b Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Fri, 24 Jun 2011 20:46:31 +0100 Subject: [PATCH] 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 --- 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 c914729f9554..9b4cfdb09516 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 384cfe3b1be1..d725a8fbe1a6 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 60176e873d62..a4c7830ec9b0 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 e8d5f03a89fe..c422eb2ce60a 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]; -- 2.39.2