bnx2x: Move statistics implementation into semaphores

Commit dff173de84958 ("bnx2x: Fix statistics locking scheme") changed the
bnx2x locking around statistics state into using a mutex - but the lock
is being accessed via a timer which is forbidden.

[If compiled with CONFIG_DEBUG_MUTEXES, logs show a warning about
accessing the mutex in interrupt context]

This moves the implementation into using a semaphore [with size '1']
instead.

Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
index a3b0f7a..1f82a04 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
@@ -1774,7 +1774,7 @@ struct bnx2x {
        int                     stats_state;
 
        /* used for synchronization of concurrent threads statistics handling */
-       struct mutex            stats_lock;
+       struct semaphore        stats_lock;
 
        /* used by dmae command loader */
        struct dmae_command     stats_dmae;

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
index fd52ce9..33501bc 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
@@ -12054,7 +12054,7 @@ static int bnx2x_init_bp(struct bnx2x *bp)
        mutex_init(&bp->port.phy_mutex);
        mutex_init(&bp->fw_mb_mutex);
        mutex_init(&bp->drv_info_mutex);
-       mutex_init(&bp->stats_lock);
+       sema_init(&bp->stats_lock, 1);
        bp->drv_info_mng_owner = false;
 
        INIT_DELAYED_WORK(&bp->sp_task, bnx2x_sp_task);
@@ -13690,9 +13690,10 @@ static int bnx2x_eeh_nic_unload(struct bnx2x *bp)
        cancel_delayed_work_sync(&bp->sp_task);
        cancel_delayed_work_sync(&bp->period_task);
 
-       mutex_lock(&bp->stats_lock);
-       bp->stats_state = STATS_STATE_DISABLED;
-       mutex_unlock(&bp->stats_lock);
+       if (!down_timeout(&bp->stats_lock, HZ / 10)) {
+               bp->stats_state = STATS_STATE_DISABLED;
+               up(&bp->stats_lock);
+       }
 
        bnx2x_save_statistics(bp);
 

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c
index 266b055..69d699f 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c
@@ -1372,19 +1372,23 @@ void bnx2x_stats_handle(struct bnx2x *bp, enum bnx2x_stats_event event)
         * that context in case someone is in the middle of a transition.
         * For other events, wait a bit until lock is taken.
         */
-       if (!mutex_trylock(&bp->stats_lock)) {
+       if (down_trylock(&bp->stats_lock)) {
                if (event == STATS_EVENT_UPDATE)
                        return;
 
                DP(BNX2X_MSG_STATS,
                   "Unlikely stats' lock contention [event %d]\n", event);
-               mutex_lock(&bp->stats_lock);
+               if (unlikely(down_timeout(&bp->stats_lock, HZ / 10))) {
+                       BNX2X_ERR("Failed to take stats lock [event %d]\n",
+                                 event);
+                       return;
+               }
        }
 
        bnx2x_stats_stm[state][event].action(bp);
        bp->stats_state = bnx2x_stats_stm[state][event].next_state;
 
-       mutex_unlock(&bp->stats_lock);
+       up(&bp->stats_lock);
 
        if ((event != STATS_EVENT_UPDATE) || netif_msg_timer(bp))
                DP(BNX2X_MSG_STATS, "state %d -> event %d -> state %d\n",
@@ -1970,7 +1974,11 @@ int bnx2x_stats_safe_exec(struct bnx2x *bp,
        /* Wait for statistics to end [while blocking further requests],
         * then run supplied function 'safely'.
         */
-       mutex_lock(&bp->stats_lock);
+       rc = down_timeout(&bp->stats_lock, HZ / 10);
+       if (unlikely(rc)) {
+               BNX2X_ERR("Failed to take statistics lock for safe execution\n");
+               goto out_no_lock;
+       }
 
        bnx2x_stats_comp(bp);
        while (bp->stats_pending && cnt--)
@@ -1988,7 +1996,7 @@ out:
        /* No need to restart statistics - if they're enabled, the timer
         * will restart the statistics.
         */
-       mutex_unlock(&bp->stats_lock);
-
+       up(&bp->stats_lock);
+out_no_lock:
        return rc;
 }