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Commit c6e36d8c authored by Yuval Mintz's avatar Yuval Mintz Committed by David S. Miller
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bnx2x: Move statistics implementation into semaphores 



Commit dff173de ("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: default avatarYuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: default avatarAriel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 31a41898

drivers/net/ethernet/broadcom/bnx2x/bnx2x.h

+1 −1
Original line number Diff line number Diff line
@@ -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;

drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c

+5 −4
Original line number Diff line number Diff line
@@ -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);

	if (!down_timeout(&bp->stats_lock, HZ / 10)) {

		bp->stats_state = STATS_STATE_DISABLED;

	mutex_unlock(&bp->stats_lock);

		up(&bp->stats_lock);

	}



	bnx2x_save_statistics(bp);

drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c

+14 −6
Original line number Diff line number Diff line
@@ -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 @@ int bnx2x_stats_safe_exec(struct bnx2x *bp, 
	/* 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;

}