[PATCH AUTOSEL 5.13 149/219] iavf: use mutexes for locking of critical sections

Sasha Levin
2021-09-09T12:24:51Z

From: Stefan Assmann <sassmann@kpanic.de>

[ Upstream commit 5ac49f3c2702f269d31cc37eb9308bc557953c4d ]

As follow-up to the discussion with Jakub Kicinski about iavf locking
being insufficient [1] convert iavf to use mutexes instead of bitops.
The locking logic is kept as is, just a drop-in replacement of
enum iavf_critical_section_t with separate mutexes.
The only difference is that the mutexes will be destroyed before the
module is unloaded.

[1] https://lwn.net/ml/netdev/20210316150210.00007249%40intel.com/

Signed-off-by: Stefan Assmann <sassmann@kpanic.de>
Tested-by: Marek Szlosek <marek.szlosek@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/intel/iavf/iavf.h | 9 +-
.../net/ethernet/intel/iavf/iavf_ethtool.c | 10 +-
drivers/net/ethernet/intel/iavf/iavf_main.c | 100 +++++++++---------
3 files changed, 56 insertions(+), 63 deletions(-)

diff --git a/drivers/net/ethernet/intel/iavf/iavf.h b/drivers/net/ethernet/intel/iavf/iavf.h
index 90793b36126e..68c80f04113c 100644
--- a/drivers/net/ethernet/intel/iavf/iavf.h
+++ b/drivers/net/ethernet/intel/iavf/iavf.h
@@ -186,12 +186,6 @@ enum iavf_state_t {
__IAVF_RUNNING, /* opened, working */
};

-enum iavf_critical_section_t {
- __IAVF_IN_CRITICAL_TASK, /* cannot be interrupted */
- __IAVF_IN_CLIENT_TASK,
- __IAVF_IN_REMOVE_TASK, /* device being removed */
-};
-
#define IAVF_CLOUD_FIELD_OMAC 0x01
#define IAVF_CLOUD_FIELD_IMAC 0x02
#define IAVF_CLOUD_FIELD_IVLAN 0x04
@@ -236,6 +230,9 @@ struct iavf_adapter {
struct iavf_q_vector *q_vectors;
struct list_head vlan_filter_list;
struct list_head mac_filter_list;
+ struct mutex crit_lock;
+ struct mutex client_lock;
+ struct mutex remove_lock;
/* Lock to protect accesses to MAC and VLAN lists */
spinlock_t mac_vlan_list_lock;
char misc_vector_name[IFNAMSIZ + 9];
diff --git a/drivers/net/ethernet/intel/iavf/iavf_ethtool.c b/drivers/net/ethernet/intel/iavf/iavf_ethtool.c
index af43fbd8cb75..edbeb27213f8 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_ethtool.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_ethtool.c
@@ -1352,8 +1352,7 @@ static int iavf_add_fdir_ethtool(struct iavf_adapter *adapter, struct ethtool_rx
if (!fltr)
return -ENOMEM;

- while (test_and_set_bit(__IAVF_IN_CRITICAL_TASK,
- &adapter->crit_section)) {
+ while (!mutex_trylock(&adapter->crit_lock)) {
if (--count == 0) {
kfree(fltr);
return -EINVAL;
@@ -1378,7 +1377,7 @@ static int iavf_add_fdir_ethtool(struct iavf_adapter *adapter, struct ethtool_rx
if (err && fltr)
kfree(fltr);

- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);
return err;
}

@@ -1563,8 +1562,7 @@ iavf_set_adv_rss_hash_opt(struct iavf_adapter *adapter,
return -EINVAL;
}

- while (test_and_set_bit(__IAVF_IN_CRITICAL_TASK,
- &adapter->crit_section)) {
+ while (!mutex_trylock(&adapter->crit_lock)) {
if (--count == 0) {
kfree(rss_new);
return -EINVAL;
@@ -1600,7 +1598,7 @@ iavf_set_adv_rss_hash_opt(struct iavf_adapter *adapter,
if (!err)
mod_delayed_work(iavf_wq, &adapter->watchdog_task, 0);

- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);

if (!rss_new_add)
kfree(rss_new);
diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
index e5e6a5b11e6d..23762a7ef740 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_main.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
@@ -132,21 +132,18 @@ enum iavf_status iavf_free_virt_mem_d(struct iavf_hw *hw,
}

/**
- * iavf_lock_timeout - try to set bit but give up after timeout
- * @adapter: board private structure
- * @bit: bit to set
+ * iavf_lock_timeout - try to lock mutex but give up after timeout
+ * @lock: mutex that should be locked
* @msecs: timeout in msecs
*
* Returns 0 on success, negative on failure
**/
-static int iavf_lock_timeout(struct iavf_adapter *adapter,
- enum iavf_critical_section_t bit,
- unsigned int msecs)
+static int iavf_lock_timeout(struct mutex *lock, unsigned int msecs)
{
unsigned int wait, delay = 10;

for (wait = 0; wait < msecs; wait += delay) {
- if (!test_and_set_bit(bit, &adapter->crit_section))
+ if (mutex_trylock(lock))
return 0;

msleep(delay);
@@ -1940,7 +1937,7 @@ static void iavf_watchdog_task(struct work_struct *work)
struct iavf_hw *hw = &adapter->hw;
u32 reg_val;

- if (test_and_set_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section))
+ if (!mutex_trylock(&adapter->crit_lock))
goto restart_watchdog;

if (adapter->flags & IAVF_FLAG_PF_COMMS_FAILED)
@@ -1958,8 +1955,7 @@ static void iavf_watchdog_task(struct work_struct *work)
adapter->state = __IAVF_STARTUP;
adapter->flags &= ~IAVF_FLAG_PF_COMMS_FAILED;
queue_delayed_work(iavf_wq, &adapter->init_task, 10);
- clear_bit(__IAVF_IN_CRITICAL_TASK,
- &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);
/* Don't reschedule the watchdog, since we've restarted
* the init task. When init_task contacts the PF and
* gets everything set up again, it'll restart the
@@ -1969,14 +1965,13 @@ static void iavf_watchdog_task(struct work_struct *work)
}
adapter->aq_required = 0;
adapter->current_op = VIRTCHNL_OP_UNKNOWN;
- clear_bit(__IAVF_IN_CRITICAL_TASK,
- &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);
queue_delayed_work(iavf_wq,
&adapter->watchdog_task,
msecs_to_jiffies(10));
goto watchdog_done;
case __IAVF_RESETTING:
- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);
queue_delayed_work(iavf_wq, &adapter->watchdog_task, HZ * 2);
return;
case __IAVF_DOWN:
@@ -1999,7 +1994,7 @@ static void iavf_watchdog_task(struct work_struct *work)
}
break;
case __IAVF_REMOVE:
- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);
return;
default:
goto restart_watchdog;
@@ -2021,7 +2016,7 @@ static void iavf_watchdog_task(struct work_struct *work)
if (adapter->state == __IAVF_RUNNING ||
adapter->state == __IAVF_COMM_FAILED)
iavf_detect_recover_hung(&adapter->vsi);
- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);
restart_watchdog:
if (adapter->aq_required)
queue_delayed_work(iavf_wq, &adapter->watchdog_task,
@@ -2085,7 +2080,7 @@ static void iavf_disable_vf(struct iavf_adapter *adapter)
memset(adapter->vf_res, 0, IAVF_VIRTCHNL_VF_RESOURCE_SIZE);
iavf_shutdown_adminq(&adapter->hw);
adapter->netdev->flags &= ~IFF_UP;
- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);
adapter->flags &= ~IAVF_FLAG_RESET_PENDING;
adapter->state = __IAVF_DOWN;
wake_up(&adapter->down_waitqueue);
@@ -2118,15 +2113,14 @@ static void iavf_reset_task(struct work_struct *work)
/* When device is being removed it doesn't make sense to run the reset
* task, just return in such a case.
*/
- if (test_bit(__IAVF_IN_REMOVE_TASK, &adapter->crit_section))
+ if (mutex_is_locked(&adapter->remove_lock))
return;

- if (iavf_lock_timeout(adapter, __IAVF_IN_CRITICAL_TASK, 200)) {
+ if (iavf_lock_timeout(&adapter->crit_lock, 200)) {
schedule_work(&adapter->reset_task);
return;
}
- while (test_and_set_bit(__IAVF_IN_CLIENT_TASK,
- &adapter->crit_section))
+ while (!mutex_trylock(&adapter->client_lock))
usleep_range(500, 1000);
if (CLIENT_ENABLED(adapter)) {
adapter->flags &= ~(IAVF_FLAG_CLIENT_NEEDS_OPEN |
@@ -2178,7 +2172,7 @@ static void iavf_reset_task(struct work_struct *work)
dev_err(&adapter->pdev->dev, "Reset never finished (%x)\n",
reg_val);
iavf_disable_vf(adapter);
- clear_bit(__IAVF_IN_CLIENT_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->client_lock);
return; /* Do not attempt to reinit. It's dead, Jim. */
}

@@ -2305,13 +2299,13 @@ static void iavf_reset_task(struct work_struct *work)
adapter->state = __IAVF_DOWN;
wake_up(&adapter->down_waitqueue);
}
- clear_bit(__IAVF_IN_CLIENT_TASK, &adapter->crit_section);
- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->client_lock);
+ mutex_unlock(&adapter->crit_lock);

return;
reset_err:
- clear_bit(__IAVF_IN_CLIENT_TASK, &adapter->crit_section);
- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->client_lock);
+ mutex_unlock(&adapter->crit_lock);
dev_err(&adapter->pdev->dev, "failed to allocate resources during reinit\n");
iavf_close(netdev);
}
@@ -2339,7 +2333,7 @@ static void iavf_adminq_task(struct work_struct *work)
if (!event.msg_buf)
goto out;

- if (iavf_lock_timeout(adapter, __IAVF_IN_CRITICAL_TASK, 200))
+ if (iavf_lock_timeout(&adapter->crit_lock, 200))
goto freedom;
do {
ret = iavf_clean_arq_element(hw, &event, &pending);
@@ -2354,7 +2348,7 @@ static void iavf_adminq_task(struct work_struct *work)
if (pending != 0)
memset(event.msg_buf, 0, IAVF_MAX_AQ_BUF_SIZE);
} while (pending);
- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);

if ((adapter->flags &
(IAVF_FLAG_RESET_PENDING | IAVF_FLAG_RESET_NEEDED)) ||
@@ -2421,7 +2415,7 @@ static void iavf_client_task(struct work_struct *work)
* later.
*/

- if (test_and_set_bit(__IAVF_IN_CLIENT_TASK, &adapter->crit_section))
+ if (!mutex_trylock(&adapter->client_lock))
return;

if (adapter->flags & IAVF_FLAG_SERVICE_CLIENT_REQUESTED) {
@@ -2444,7 +2438,7 @@ static void iavf_client_task(struct work_struct *work)
adapter->flags &= ~IAVF_FLAG_CLIENT_NEEDS_OPEN;
}
out:
- clear_bit(__IAVF_IN_CLIENT_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->client_lock);
}

/**
@@ -3047,8 +3041,7 @@ static int iavf_configure_clsflower(struct iavf_adapter *adapter,
if (!filter)
return -ENOMEM;

- while (test_and_set_bit(__IAVF_IN_CRITICAL_TASK,
- &adapter->crit_section)) {
+ while (!mutex_trylock(&adapter->crit_lock)) {
if (--count == 0)
goto err;
udelay(1);
@@ -3079,7 +3072,7 @@ static int iavf_configure_clsflower(struct iavf_adapter *adapter,
if (err)
kfree(filter);

- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);
return err;
}

@@ -3226,8 +3219,7 @@ static int iavf_open(struct net_device *netdev)
return -EIO;
}

- while (test_and_set_bit(__IAVF_IN_CRITICAL_TASK,
- &adapter->crit_section))
+ while (!mutex_trylock(&adapter->crit_lock))
usleep_range(500, 1000);

if (adapter->state != __IAVF_DOWN) {
@@ -3262,7 +3254,7 @@ static int iavf_open(struct net_device *netdev)

iavf_irq_enable(adapter, true);

- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);

return 0;

@@ -3274,7 +3266,7 @@ static int iavf_open(struct net_device *netdev)
err_setup_tx:
iavf_free_all_tx_resources(adapter);
err_unlock:
- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);

return err;
}
@@ -3298,8 +3290,7 @@ static int iavf_close(struct net_device *netdev)
if (adapter->state <= __IAVF_DOWN_PENDING)
return 0;

- while (test_and_set_bit(__IAVF_IN_CRITICAL_TASK,
- &adapter->crit_section))
+ while (!mutex_trylock(&adapter->crit_lock))
usleep_range(500, 1000);

set_bit(__IAVF_VSI_DOWN, adapter->vsi.state);
@@ -3310,7 +3301,7 @@ static int iavf_close(struct net_device *netdev)
adapter->state = __IAVF_DOWN_PENDING;
iavf_free_traffic_irqs(adapter);

- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);

/* We explicitly don't free resources here because the hardware is
* still active and can DMA into memory. Resources are cleared in
@@ -3659,8 +3650,8 @@ static void iavf_init_task(struct work_struct *work)
init_task.work);
struct iavf_hw *hw = &adapter->hw;

- if (iavf_lock_timeout(adapter, __IAVF_IN_CRITICAL_TASK, 5000)) {
- dev_warn(&adapter->pdev->dev, "failed to set __IAVF_IN_CRITICAL_TASK in %s\n", __FUNCTION__);
+ if (iavf_lock_timeout(&adapter->crit_lock, 5000)) {
+ dev_warn(&adapter->pdev->dev, "failed to acquire crit_lock in %s\n", __FUNCTION__);
return;
}
switch (adapter->state) {
@@ -3695,7 +3686,7 @@ static void iavf_init_task(struct work_struct *work)
}
queue_delayed_work(iavf_wq, &adapter->init_task, HZ);
out:
- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);
}

/**
@@ -3712,12 +3703,12 @@ static void iavf_shutdown(struct pci_dev *pdev)
if (netif_running(netdev))
iavf_close(netdev);

- if (iavf_lock_timeout(adapter, __IAVF_IN_CRITICAL_TASK, 5000))
- dev_warn(&adapter->pdev->dev, "failed to set __IAVF_IN_CRITICAL_TASK in %s\n", __FUNCTION__);
+ if (iavf_lock_timeout(&adapter->crit_lock, 5000))
+ dev_warn(&adapter->pdev->dev, "failed to acquire crit_lock in %s\n", __FUNCTION__);
/* Prevent the watchdog from running. */
adapter->state = __IAVF_REMOVE;
adapter->aq_required = 0;
- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);

#ifdef CONFIG_PM
pci_save_state(pdev);
@@ -3811,6 +3802,9 @@ static int iavf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
/* set up the locks for the AQ, do this only once in probe
* and destroy them only once in remove
*/
+ mutex_init(&adapter->crit_lock);
+ mutex_init(&adapter->client_lock);
+ mutex_init(&adapter->remove_lock);
mutex_init(&hw->aq.asq_mutex);
mutex_init(&hw->aq.arq_mutex);

@@ -3862,8 +3856,7 @@ static int __maybe_unused iavf_suspend(struct device *dev_d)

netif_device_detach(netdev);

- while (test_and_set_bit(__IAVF_IN_CRITICAL_TASK,
- &adapter->crit_section))
+ while (!mutex_trylock(&adapter->crit_lock))
usleep_range(500, 1000);

if (netif_running(netdev)) {
@@ -3874,7 +3867,7 @@ static int __maybe_unused iavf_suspend(struct device *dev_d)
iavf_free_misc_irq(adapter);
iavf_reset_interrupt_capability(adapter);

- clear_bit(__IAVF_IN_CRITICAL_TASK, &adapter->crit_section);
+ mutex_unlock(&adapter->crit_lock);

return 0;
}
@@ -3936,7 +3929,7 @@ static void iavf_remove(struct pci_dev *pdev)
struct iavf_hw *hw = &adapter->hw;
int err;
/* Indicate we are in remove and not to run reset_task */
- set_bit(__IAVF_IN_REMOVE_TASK, &adapter->crit_section);
+ mutex_lock(&adapter->remove_lock);
cancel_delayed_work_sync(&adapter->init_task);
cancel_work_sync(&adapter->reset_task);
cancel_delayed_work_sync(&adapter->client_task);
@@ -3958,8 +3951,8 @@ static void iavf_remove(struct pci_dev *pdev)
iavf_request_reset(adapter);
msleep(50);
}
- if (iavf_lock_timeout(adapter, __IAVF_IN_CRITICAL_TASK, 5000))
- dev_warn(&adapter->pdev->dev, "failed to set __IAVF_IN_CRITICAL_TASK in %s\n", __FUNCTION__);
+ if (iavf_lock_timeout(&adapter->crit_lock, 5000))
+ dev_warn(&adapter->pdev->dev, "failed to acquire crit_lock in %s\n", __FUNCTION__);

/* Shut down all the garbage mashers on the detention level */
adapter->state = __IAVF_REMOVE;
@@ -3984,6 +3977,11 @@ static void iavf_remove(struct pci_dev *pdev)
/* destroy the locks only once, here */
mutex_destroy(&hw->aq.arq_mutex);
mutex_destroy(&hw->aq.asq_mutex);
+ mutex_destroy(&adapter->client_lock);
+ mutex_unlock(&adapter->crit_lock);
+ mutex_destroy(&adapter->crit_lock);
+ mutex_unlock(&adapter->remove_lock);
+ mutex_destroy(&adapter->remove_lock);

iounmap(hw->hw_addr);
pci_release_regions(pdev);
--
2.30.2