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Commit 525d9e82 authored by Daniel Pieczko's avatar Daniel Pieczko Committed by Ben Hutchings
Browse files

sfc: Work-around flush timeout when flushes have completed 



We sometimes hit a "failed to flush" timeout on some TX queues, but the
flushes have completed and the flush completion events seem to go missing.
In this case, we can check the TX_DESC_PTR_TBL register and drain the
queues if the flushes had finished.

[bwh: Minor fixes to coding style]
Signed-off-by: default avatarBen Hutchings <bhutchings@solarflare.com>
parent 876be083

drivers/net/ethernet/sfc/net_driver.h

+1 −0
Original line number Diff line number Diff line
@@ -200,6 +200,7 @@ struct efx_tx_queue { 
	/* Members shared between paths and sometimes updated */

	unsigned int empty_read_count ____cacheline_aligned_in_smp;

#define EFX_EMPTY_COUNT_VALID 0x80000000

	atomic_t flush_outstanding;

};



/**

drivers/net/ethernet/sfc/nic.c

+52 −4
Original line number Diff line number Diff line
@@ -73,6 +73,8 @@ 
	_EFX_CHANNEL_MAGIC(_EFX_CHANNEL_MAGIC_TX_DRAIN,			\

			   (_tx_queue)->queue)



static void efx_magic_event(struct efx_channel *channel, u32 magic);



/**************************************************************************

 *

 * Solarstorm hardware access
@@ -491,6 +493,9 @@ static void efx_flush_tx_queue(struct efx_tx_queue *tx_queue) 
	struct efx_nic *efx = tx_queue->efx;

	efx_oword_t tx_flush_descq;



	WARN_ON(atomic_read(&tx_queue->flush_outstanding));

	atomic_set(&tx_queue->flush_outstanding, 1);



	EFX_POPULATE_OWORD_2(tx_flush_descq,

			     FRF_AZ_TX_FLUSH_DESCQ_CMD, 1,

			     FRF_AZ_TX_FLUSH_DESCQ, tx_queue->queue);
@@ -666,6 +671,47 @@ static bool efx_flush_wake(struct efx_nic *efx) 
		 && atomic_read(&efx->rxq_flush_pending) > 0));

}



static bool efx_check_tx_flush_complete(struct efx_nic *efx)

{

	bool i = true;

	efx_oword_t txd_ptr_tbl;

	struct efx_channel *channel;

	struct efx_tx_queue *tx_queue;



	efx_for_each_channel(channel, efx) {

		efx_for_each_channel_tx_queue(tx_queue, channel) {

			efx_reado_table(efx, &txd_ptr_tbl,

					FR_BZ_TX_DESC_PTR_TBL, tx_queue->queue);

			if (EFX_OWORD_FIELD(txd_ptr_tbl,

					    FRF_AZ_TX_DESCQ_FLUSH) ||

			    EFX_OWORD_FIELD(txd_ptr_tbl,

					    FRF_AZ_TX_DESCQ_EN)) {

				netif_dbg(efx, hw, efx->net_dev,

					  "flush did not complete on TXQ %d\n",

					  tx_queue->queue);

				i = false;

			} else if (atomic_cmpxchg(&tx_queue->flush_outstanding,

						  1, 0)) {

				/* The flush is complete, but we didn't

				 * receive a flush completion event

				 */

				netif_dbg(efx, hw, efx->net_dev,

					  "flush complete on TXQ %d, so drain "

					  "the queue\n", tx_queue->queue);

				/* Don't need to increment drain_pending as it

				 * has already been incremented for the queues

				 * which did not drain

				 */

				efx_magic_event(channel,

						EFX_CHANNEL_MAGIC_TX_DRAIN(

							tx_queue));

			}

		}

	}



	return i;

}



/* Flush all the transmit queues, and continue flushing receive queues until

 * they're all flushed. Wait for the DRAIN events to be recieved so that there

 * are no more RX and TX events left on any channel. */
@@ -726,7 +772,8 @@ int efx_nic_flush_queues(struct efx_nic *efx) 
					     timeout);

	}



	if (atomic_read(&efx->drain_pending)) {

	if (atomic_read(&efx->drain_pending) &&

	    !efx_check_tx_flush_complete(efx)) {

		netif_err(efx, hw, efx->net_dev, "failed to flush %d queues "

			  "(rx %d+%d)\n", atomic_read(&efx->drain_pending),

			  atomic_read(&efx->rxq_flush_outstanding),
@@ -1018,11 +1065,12 @@ efx_handle_tx_flush_done(struct efx_nic *efx, efx_qword_t *event) 
	if (qid < EFX_TXQ_TYPES * efx->n_tx_channels) {

		tx_queue = efx_get_tx_queue(efx, qid / EFX_TXQ_TYPES,

					    qid % EFX_TXQ_TYPES);



		if (atomic_cmpxchg(&tx_queue->flush_outstanding, 1, 0)) {

			efx_magic_event(tx_queue->channel,

					EFX_CHANNEL_MAGIC_TX_DRAIN(tx_queue));

		}

	}

}



/* If this flush done event corresponds to a &struct efx_rx_queue: If the flush

 * was succesful then send an %EFX_CHANNEL_MAGIC_RX_DRAIN, otherwise add