[PATCH v4 1/2] net/ibmvnic: unlock rtnl_lock in reset so linkwatch_event can run
Juliet Kim
julietk at linux.vnet.ibm.com
Sat Sep 21 06:11:22 AEST 2019
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 <julietk at linux.vnet.ibm.com>
---
drivers/net/ethernet/ibm/ibmvnic.c | 224 ++++++++++++++++++++++++++-----------
drivers/net/ethernet/ibm/ibmvnic.h | 1 +
2 files changed, 157 insertions(+), 68 deletions(-)
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 5cb55ea671e3..ba340aaff1b3 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
--
2.16.4
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