[PATCH 1/2] net/ibmvnic: unlock rtnl_lock in reset so linkwatch_event can run
Juliet Kim
julietk at linux.vnet.ibm.com
Wed Aug 21 07:31:19 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 | 144 +++++++++++++++++++++++++++----------
1 file changed, 108 insertions(+), 36 deletions(-)
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index cebd20f3128d..a3e2fbb9c5db 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1733,11 +1733,21 @@ static int do_reset(struct ibmvnic_adapter *adapter,
u64 old_num_rx_queues, old_num_tx_queues;
u64 old_num_rx_slots, old_num_tx_slots;
struct net_device *netdev = adapter->netdev;
+ bool we_lock_rtnl = false;
int i, rc;
netdev_dbg(adapter->netdev, "Re-setting driver (%d)\n",
rwi->reset_reason);
+ /* 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 && !we_lock_rtnl) {
+ rtnl_lock();
+ we_lock_rtnl = true;
+ }
+
netif_carrier_off(netdev);
adapter->reset_reason = rwi->reset_reason;
@@ -1751,9 +1761,27 @@ 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;
+ if (!adapter->wait_for_reset && we_lock_rtnl) {
+ we_lock_rtnl = false;
+ rtnl_unlock();
+ }
+
+ rc = set_link_state(adapter, IBMVNIC_LOGICAL_LNK_DN);
if (rc)
- return rc;
+ goto out;
+
+ if (!adapter->wait_for_reset && !we_lock_rtnl) {
+ rtnl_lock();
+ we_lock_rtnl = true;
+ }
+
+ if (adapter->state != VNIC_CLOSING) {
+ rc = -1;
+ goto out;
+ }
+
+ adapter->state = VNIC_CLOSED;
}
if (adapter->reset_reason == VNIC_RESET_CHANGE_PARAM ||
@@ -1783,30 +1811,34 @@ 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;
+ goto out;
} 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 !=
@@ -1820,23 +1852,25 @@ 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) {
@@ -1845,7 +1879,8 @@ static int do_reset(struct ibmvnic_adapter *adapter,
else
adapter->state = reset_state;
- return 0;
+ rc = 0;
+ goto out;
}
/* refresh device's multicast list */
@@ -1859,18 +1894,42 @@ static int do_reset(struct ibmvnic_adapter *adapter,
adapter->reset_reason != VNIC_RESET_CHANGE_PARAM)
call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, netdev);
+ if (!adapter->wait_for_reset && we_lock_rtnl) {
+ rtnl_unlock();
+ we_lock_rtnl = false;
+ }
+
return 0;
+
+out:
+ if (!adapter->wait_for_reset && we_lock_rtnl) {
+ rtnl_unlock();
+ we_lock_rtnl = false;
+ }
+
+ return rc;
}
static int do_hard_reset(struct ibmvnic_adapter *adapter,
struct ibmvnic_rwi *rwi, u32 reset_state)
{
struct net_device *netdev = adapter->netdev;
+ bool we_lock_rtnl = false;
int rc;
netdev_dbg(adapter->netdev, "Hard resetting driver (%d)\n",
rwi->reset_reason);
+ /* 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 && !we_lock_rtnl) {
+ rtnl_lock();
+ we_lock_rtnl = true;
+ }
+
+ adapter->force_reset_recovery = false;
netif_carrier_off(netdev);
adapter->reset_reason = rwi->reset_reason;
@@ -1889,34 +1948,39 @@ static int do_hard_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_init(adapter);
if (rc)
- return rc;
+ 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 = VNIC_PROBED;
- return 0;
+ rc = 0;
+ goto out;
}
rc = init_resources(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) {
@@ -1925,10 +1989,25 @@ static int do_hard_reset(struct ibmvnic_adapter *adapter,
else
adapter->state = reset_state;
- return 0;
+ rc = 0;
+ goto out;
+ }
+
+ if (!adapter->wait_for_reset && we_lock_rtnl) {
+ rtnl_unlock();
+ we_lock_rtnl = false;
}
return 0;
+
+out:
+ if (!adapter->wait_for_reset && we_lock_rtnl) {
+ rtnl_unlock();
+ we_lock_rtnl = false;
+ }
+
+ return rc;
+
}
static struct ibmvnic_rwi *get_next_rwi(struct ibmvnic_adapter *adapter)
@@ -1965,26 +2044,16 @@ 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);
while (rwi) {
if (adapter->force_reset_recovery) {
- adapter->force_reset_recovery = false;
rc = do_hard_reset(adapter, rwi, reset_state);
} else {
rc = do_reset(adapter, rwi, reset_state);
@@ -1995,6 +2064,11 @@ static void __ibmvnic_reset(struct work_struct *work)
break;
rwi = get_next_rwi(adapter);
+
+ if (rwi && (rwi->reset_reason == VNIC_RESET_FAILOVER ||
+ rwi->reset_reason == VNIC_RESET_MOBILITY) &&
+ !adapter->force_reset_recovery)
+ adapter->force_reset_recovery = true;
}
if (adapter->wait_for_reset) {
@@ -2009,8 +2083,6 @@ 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,
--
2.16.4
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