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Commit a551ee94 authored by Michael Chan's avatar Michael Chan Committed by David S. Miller
Browse files

bnxt_en: Fix bnxt_reset() in the slow path task. 



In bnxt_sp_task(), we set a bit BNXT_STATE_IN_SP_TASK so that bnxt_close()
will synchronize and wait for bnxt_sp_task() to finish.  Some functions
in bnxt_sp_task() require us to clear BNXT_STATE_IN_SP_TASK and then
acquire rtnl_lock() to prevent race conditions.

There are some bugs related to this logic. This patch refactors the code
to have common bnxt_rtnl_lock_sp() and bnxt_rtnl_unlock_sp() to handle
the RTNL and the clearing/setting of the bit.  Multiple functions will
need the same logic.  We also need to move bnxt_reset() to the end of
bnxt_sp_task().  Functions that clear BNXT_STATE_IN_SP_TASK must be the
last functions to be called in bnxt_sp_task().  The common scheme will
handle the condition properly.

Signed-off-by: default avatarMichael Chan <michael.chan@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 56d80622

drivers/net/ethernet/broadcom/bnxt/bnxt.c

+25 −13
Original line number Diff line number Diff line
@@ -6200,23 +6200,32 @@ static void bnxt_timer(unsigned long data) 
	mod_timer(&bp->timer, jiffies + bp->current_interval);

}



/* Only called from bnxt_sp_task() */

static void bnxt_reset(struct bnxt *bp, bool silent)

static void bnxt_rtnl_lock_sp(struct bnxt *bp)

{

	/* bnxt_reset_task() calls bnxt_close_nic() which waits

	 * for BNXT_STATE_IN_SP_TASK to clear.

	 * If there is a parallel dev_close(), bnxt_close() may be holding

	/* We are called from bnxt_sp_task which has BNXT_STATE_IN_SP_TASK

	 * set.  If the device is being closed, bnxt_close() may be holding

	 * rtnl() and waiting for BNXT_STATE_IN_SP_TASK to clear.  So we

	 * must clear BNXT_STATE_IN_SP_TASK before holding rtnl().

	 */

	clear_bit(BNXT_STATE_IN_SP_TASK, &bp->state);

	rtnl_lock();

	if (test_bit(BNXT_STATE_OPEN, &bp->state))

		bnxt_reset_task(bp, silent);

}



static void bnxt_rtnl_unlock_sp(struct bnxt *bp)

{

	set_bit(BNXT_STATE_IN_SP_TASK, &bp->state);

	rtnl_unlock();

}



/* Only called from bnxt_sp_task() */

static void bnxt_reset(struct bnxt *bp, bool silent)

{

	bnxt_rtnl_lock_sp(bp);

	if (test_bit(BNXT_STATE_OPEN, &bp->state))

		bnxt_reset_task(bp, silent);

	bnxt_rtnl_unlock_sp(bp);

}



static void bnxt_cfg_ntp_filters(struct bnxt *);



static void bnxt_sp_task(struct work_struct *work)
@@ -6266,18 +6275,21 @@ static void bnxt_sp_task(struct work_struct *work) 
		bnxt_hwrm_tunnel_dst_port_free(

			bp, TUNNEL_DST_PORT_FREE_REQ_TUNNEL_TYPE_GENEVE);

	}

	if (test_and_clear_bit(BNXT_RESET_TASK_SP_EVENT, &bp->sp_event))

		bnxt_reset(bp, false);



	if (test_and_clear_bit(BNXT_RESET_TASK_SILENT_SP_EVENT, &bp->sp_event))

		bnxt_reset(bp, true);



	if (test_and_clear_bit(BNXT_HWRM_PORT_MODULE_SP_EVENT, &bp->sp_event))

		bnxt_get_port_module_status(bp);



	if (test_and_clear_bit(BNXT_PERIODIC_STATS_SP_EVENT, &bp->sp_event))

		bnxt_hwrm_port_qstats(bp);



	/* These functions below will clear BNXT_STATE_IN_SP_TASK.  They

	 * must be the last functions to be called before exiting.

	 */

	if (test_and_clear_bit(BNXT_RESET_TASK_SP_EVENT, &bp->sp_event))

		bnxt_reset(bp, false);



	if (test_and_clear_bit(BNXT_RESET_TASK_SILENT_SP_EVENT, &bp->sp_event))

		bnxt_reset(bp, true);



	smp_mb__before_atomic();

	clear_bit(BNXT_STATE_IN_SP_TASK, &bp->state);

}