From: Juliet Kim Date: Fri, 20 Sep 2019 20:11:22 +0000 (-0400) Subject: net/ibmvnic: unlock rtnl_lock in reset so linkwatch_event can run X-Git-Tag: v5.4-rc1~14^2~55^2~1 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=b27507bb59ed504d7fa4d6a35f25a8cc39903b54;p=linux.git net/ibmvnic: unlock rtnl_lock in reset so linkwatch_event can run Commit a5681e20b541 ("net/ibmnvic: Fix deadlock problem in reset") made the change to hold the RTNL lock during a reset to avoid deadlock but linkwatch_event is fired during the reset and needs the RTNL lock. That keeps linkwatch_event process from proceeding until the reset is complete. The reset process cannot tolerate the linkwatch_event processing after reset completes, so release the RTNL lock during the process to allow a chance for linkwatch_event to run during reset. This does not guarantee that the linkwatch_event will be processed as soon as link state changes, but is an improvement over the current code where linkwatch_event processing is always delayed, which prevents transmissions on the device from being deactivated leading transmit watchdog timer to time-out. Release the RTNL lock before link state change and re-acquire after the link state change to allow linkwatch_event to grab the RTNL lock and run during the reset. Fixes: a5681e20b541 ("net/ibmnvic: Fix deadlock problem in reset") Signed-off-by: Juliet Kim Signed-off-by: David S. Miller --- diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c index 3816fff75bb5..d7db5cc51f6a 100644 --- a/drivers/net/ethernet/ibm/ibmvnic.c +++ b/drivers/net/ethernet/ibm/ibmvnic.c @@ -1723,6 +1723,86 @@ static int ibmvnic_set_mac(struct net_device *netdev, void *p) return rc; } +/** + * do_change_param_reset returns zero if we are able to keep processing reset + * events, or non-zero if we hit a fatal error and must halt. + */ +static int do_change_param_reset(struct ibmvnic_adapter *adapter, + struct ibmvnic_rwi *rwi, + u32 reset_state) +{ + struct net_device *netdev = adapter->netdev; + int i, rc; + + netdev_dbg(adapter->netdev, "Change param resetting driver (%d)\n", + rwi->reset_reason); + + netif_carrier_off(netdev); + adapter->reset_reason = rwi->reset_reason; + + ibmvnic_cleanup(netdev); + + if (reset_state == VNIC_OPEN) { + rc = __ibmvnic_close(netdev); + if (rc) + return rc; + } + + release_resources(adapter); + release_sub_crqs(adapter, 1); + release_crq_queue(adapter); + + adapter->state = VNIC_PROBED; + + rc = init_crq_queue(adapter); + + if (rc) { + netdev_err(adapter->netdev, + "Couldn't initialize crq. rc=%d\n", rc); + return rc; + } + + rc = ibmvnic_reset_init(adapter); + if (rc) + return IBMVNIC_INIT_FAILED; + + /* If the adapter was in PROBE state prior to the reset, + * exit here. + */ + if (reset_state == VNIC_PROBED) + return 0; + + rc = ibmvnic_login(netdev); + if (rc) { + adapter->state = reset_state; + return rc; + } + + rc = init_resources(adapter); + if (rc) + return rc; + + ibmvnic_disable_irqs(adapter); + + adapter->state = VNIC_CLOSED; + + if (reset_state == VNIC_CLOSED) + return 0; + + rc = __ibmvnic_open(netdev); + if (rc) + return IBMVNIC_OPEN_FAILED; + + /* refresh device's multicast list */ + ibmvnic_set_multi(netdev); + + /* kick napi */ + for (i = 0; i < adapter->req_rx_queues; i++) + napi_schedule(&adapter->napi[i]); + + return 0; +} + /** * do_reset returns zero if we are able to keep processing reset events, or * non-zero if we hit a fatal error and must halt. @@ -1738,6 +1818,8 @@ static int do_reset(struct ibmvnic_adapter *adapter, netdev_dbg(adapter->netdev, "Re-setting driver (%d)\n", rwi->reset_reason); + rtnl_lock(); + netif_carrier_off(netdev); adapter->reset_reason = rwi->reset_reason; @@ -1751,16 +1833,25 @@ static int do_reset(struct ibmvnic_adapter *adapter, if (reset_state == VNIC_OPEN && adapter->reset_reason != VNIC_RESET_MOBILITY && adapter->reset_reason != VNIC_RESET_FAILOVER) { - rc = __ibmvnic_close(netdev); + adapter->state = VNIC_CLOSING; + + /* Release the RTNL lock before link state change and + * re-acquire after the link state change to allow + * linkwatch_event to grab the RTNL lock and run during + * a reset. + */ + rtnl_unlock(); + rc = set_link_state(adapter, IBMVNIC_LOGICAL_LNK_DN); + rtnl_lock(); if (rc) - return rc; - } + goto out; - if (adapter->reset_reason == VNIC_RESET_CHANGE_PARAM || - adapter->wait_for_reset) { - release_resources(adapter); - release_sub_crqs(adapter, 1); - release_crq_queue(adapter); + if (adapter->state != VNIC_CLOSING) { + rc = -1; + goto out; + } + + adapter->state = VNIC_CLOSED; } if (adapter->reset_reason != VNIC_RESET_NON_FATAL) { @@ -1769,9 +1860,7 @@ static int do_reset(struct ibmvnic_adapter *adapter, */ adapter->state = VNIC_PROBED; - if (adapter->wait_for_reset) { - rc = init_crq_queue(adapter); - } else if (adapter->reset_reason == VNIC_RESET_MOBILITY) { + if (adapter->reset_reason == VNIC_RESET_MOBILITY) { rc = ibmvnic_reenable_crq_queue(adapter); release_sub_crqs(adapter, 1); } else { @@ -1783,36 +1872,35 @@ static int do_reset(struct ibmvnic_adapter *adapter, if (rc) { netdev_err(adapter->netdev, "Couldn't initialize crq. rc=%d\n", rc); - return rc; + goto out; } rc = ibmvnic_reset_init(adapter); - if (rc) - return IBMVNIC_INIT_FAILED; + if (rc) { + rc = IBMVNIC_INIT_FAILED; + goto out; + } /* If the adapter was in PROBE state prior to the reset, * exit here. */ - if (reset_state == VNIC_PROBED) - return 0; + if (reset_state == VNIC_PROBED) { + rc = 0; + goto out; + } rc = ibmvnic_login(netdev); if (rc) { adapter->state = reset_state; - return rc; + goto out; } - if (adapter->reset_reason == VNIC_RESET_CHANGE_PARAM || - adapter->wait_for_reset) { - rc = init_resources(adapter); - if (rc) - return rc; - } else if (adapter->req_rx_queues != old_num_rx_queues || - adapter->req_tx_queues != old_num_tx_queues || - adapter->req_rx_add_entries_per_subcrq != - old_num_rx_slots || - adapter->req_tx_entries_per_subcrq != - old_num_tx_slots) { + if (adapter->req_rx_queues != old_num_rx_queues || + adapter->req_tx_queues != old_num_tx_queues || + adapter->req_rx_add_entries_per_subcrq != + old_num_rx_slots || + adapter->req_tx_entries_per_subcrq != + old_num_tx_slots) { release_rx_pools(adapter); release_tx_pools(adapter); release_napi(adapter); @@ -1820,32 +1908,30 @@ static int do_reset(struct ibmvnic_adapter *adapter, rc = init_resources(adapter); if (rc) - return rc; + goto out; } else { rc = reset_tx_pools(adapter); if (rc) - return rc; + goto out; rc = reset_rx_pools(adapter); if (rc) - return rc; + goto out; } ibmvnic_disable_irqs(adapter); } adapter->state = VNIC_CLOSED; - if (reset_state == VNIC_CLOSED) - return 0; + if (reset_state == VNIC_CLOSED) { + rc = 0; + goto out; + } rc = __ibmvnic_open(netdev); if (rc) { - if (list_empty(&adapter->rwi_list)) - adapter->state = VNIC_CLOSED; - else - adapter->state = reset_state; - - return 0; + rc = IBMVNIC_OPEN_FAILED; + goto out; } /* refresh device's multicast list */ @@ -1855,11 +1941,15 @@ static int do_reset(struct ibmvnic_adapter *adapter, for (i = 0; i < adapter->req_rx_queues; i++) napi_schedule(&adapter->napi[i]); - if (adapter->reset_reason != VNIC_RESET_FAILOVER && - adapter->reset_reason != VNIC_RESET_CHANGE_PARAM) + if (adapter->reset_reason != VNIC_RESET_FAILOVER) call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, netdev); - return 0; + rc = 0; + +out: + rtnl_unlock(); + + return rc; } static int do_hard_reset(struct ibmvnic_adapter *adapter, @@ -1919,14 +2009,8 @@ static int do_hard_reset(struct ibmvnic_adapter *adapter, return 0; rc = __ibmvnic_open(netdev); - if (rc) { - if (list_empty(&adapter->rwi_list)) - adapter->state = VNIC_CLOSED; - else - adapter->state = reset_state; - - return 0; - } + if (rc) + return IBMVNIC_OPEN_FAILED; return 0; } @@ -1965,20 +2049,11 @@ static void __ibmvnic_reset(struct work_struct *work) { struct ibmvnic_rwi *rwi; struct ibmvnic_adapter *adapter; - bool we_lock_rtnl = false; u32 reset_state; int rc = 0; adapter = container_of(work, struct ibmvnic_adapter, ibmvnic_reset); - /* netif_set_real_num_xx_queues needs to take rtnl lock here - * unless wait_for_reset is set, in which case the rtnl lock - * has already been taken before initializing the reset - */ - if (!adapter->wait_for_reset) { - rtnl_lock(); - we_lock_rtnl = true; - } reset_state = adapter->state; rwi = get_next_rwi(adapter); @@ -1990,14 +2065,32 @@ static void __ibmvnic_reset(struct work_struct *work) break; } - if (adapter->force_reset_recovery) { - adapter->force_reset_recovery = false; - rc = do_hard_reset(adapter, rwi, reset_state); + if (rwi->reset_reason == VNIC_RESET_CHANGE_PARAM) { + /* CHANGE_PARAM requestor holds rtnl_lock */ + rc = do_change_param_reset(adapter, rwi, reset_state); + } else if (adapter->force_reset_recovery) { + /* Transport event occurred during previous reset */ + if (adapter->wait_for_reset) { + /* Previous was CHANGE_PARAM; caller locked */ + adapter->force_reset_recovery = false; + rc = do_hard_reset(adapter, rwi, reset_state); + } else { + rtnl_lock(); + adapter->force_reset_recovery = false; + rc = do_hard_reset(adapter, rwi, reset_state); + rtnl_unlock(); + } } else { rc = do_reset(adapter, rwi, reset_state); } kfree(rwi); - if (rc && rc != IBMVNIC_INIT_FAILED && + if (rc == IBMVNIC_OPEN_FAILED) { + if (list_empty(&adapter->rwi_list)) + adapter->state = VNIC_CLOSED; + else + adapter->state = reset_state; + rc = 0; + } else if (rc && rc != IBMVNIC_INIT_FAILED && !adapter->force_reset_recovery) break; @@ -2005,7 +2098,6 @@ static void __ibmvnic_reset(struct work_struct *work) } if (adapter->wait_for_reset) { - adapter->wait_for_reset = false; adapter->reset_done_rc = rc; complete(&adapter->reset_done); } @@ -2016,8 +2108,6 @@ static void __ibmvnic_reset(struct work_struct *work) } adapter->resetting = false; - if (we_lock_rtnl) - rtnl_unlock(); } static int ibmvnic_reset(struct ibmvnic_adapter *adapter, @@ -2078,8 +2168,6 @@ static int ibmvnic_reset(struct ibmvnic_adapter *adapter, return 0; err: - if (adapter->wait_for_reset) - adapter->wait_for_reset = false; return -ret; } diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h index 70bd286f8932..9d3d35cc91d6 100644 --- a/drivers/net/ethernet/ibm/ibmvnic.h +++ b/drivers/net/ethernet/ibm/ibmvnic.h @@ -20,6 +20,7 @@ #define IBMVNIC_INVALID_MAP -1 #define IBMVNIC_STATS_TIMEOUT 1 #define IBMVNIC_INIT_FAILED 2 +#define IBMVNIC_OPEN_FAILED 3 /* basic structures plus 100 2k buffers */ #define IBMVNIC_IO_ENTITLEMENT_DEFAULT 610305