[net-next PATCH v3 3/4] net: stmmac: move TX timer arm after DMA enable

Christian Marangi
2023-10-14T09:30:42Z

Move TX timer arm call after DMA interrupt is enabled again.

The TX timer arm function changed logic and now is skipped if a napi is
already scheduled. By moving the TX timer arm call after DMA is enabled,
we permit to correctly skip if a DMA interrupt has been fired and a napi
has been scheduled again.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
.../net/ethernet/stmicro/stmmac/stmmac_main.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 5124ee87286c..240a18b97825 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2545,7 +2545,8 @@ static void stmmac_bump_dma_threshold(struct stmmac_priv *priv, u32 chan)
* @queue: TX queue index
* Description: it reclaims the transmit resources after transmission completes.
*/
-static int stmmac_tx_clean(struct stmmac_priv *priv, int budget, u32 queue)
+static int stmmac_tx_clean(struct stmmac_priv *priv, int budget, u32 queue,
+ bool *pending_packets)
{
struct stmmac_tx_queue *tx_q = &priv->dma_conf.tx_queue[queue];
struct stmmac_txq_stats *txq_stats = &priv->xstats.txq_stats[queue];
@@ -2706,7 +2707,7 @@ static int stmmac_tx_clean(struct stmmac_priv *priv, int budget, u32 queue)

/* We still have pending packets, let's call for a new scheduling */
if (tx_q->dirty_tx != tx_q->cur_tx)
- stmmac_tx_timer_arm(priv, queue);
+ *pending_packets = true;

flags = u64_stats_update_begin_irqsave(&txq_stats->syncp);
txq_stats->tx_packets += tx_packets;
@@ -5572,6 +5573,7 @@ static int stmmac_napi_poll_tx(struct napi_struct *napi, int budget)
container_of(napi, struct stmmac_channel, tx_napi);
struct stmmac_priv *priv = ch->priv_data;
struct stmmac_txq_stats *txq_stats;
+ bool pending_packets = false;
u32 chan = ch->index;
unsigned long flags;
int work_done;
@@ -5581,7 +5583,7 @@ static int stmmac_napi_poll_tx(struct napi_struct *napi, int budget)
txq_stats->napi_poll++;
u64_stats_update_end_irqrestore(&txq_stats->syncp, flags);

- work_done = stmmac_tx_clean(priv, budget, chan);
+ work_done = stmmac_tx_clean(priv, budget, chan, &pending_packets);
work_done = min(work_done, budget);

if (work_done < budget && napi_complete_done(napi, work_done)) {
@@ -5592,6 +5594,10 @@ static int stmmac_napi_poll_tx(struct napi_struct *napi, int budget)
spin_unlock_irqrestore(&ch->lock, flags);
}

+ /* TX still have packet to handle, check if we need to arm tx timer */
+ if (pending_packets)
+ stmmac_tx_timer_arm(priv, chan);
+
return work_done;
}

@@ -5600,6 +5606,7 @@ static int stmmac_napi_poll_rxtx(struct napi_struct *napi, int budget)
struct stmmac_channel *ch =
container_of(napi, struct stmmac_channel, rxtx_napi);
struct stmmac_priv *priv = ch->priv_data;
+ bool tx_pending_packets = false;
int rx_done, tx_done, rxtx_done;
struct stmmac_rxq_stats *rxq_stats;
struct stmmac_txq_stats *txq_stats;
@@ -5616,7 +5623,7 @@ static int stmmac_napi_poll_rxtx(struct napi_struct *napi, int budget)
txq_stats->napi_poll++;
u64_stats_update_end_irqrestore(&txq_stats->syncp, flags);

- tx_done = stmmac_tx_clean(priv, budget, chan);
+ tx_done = stmmac_tx_clean(priv, budget, chan, &tx_pending_packets);
tx_done = min(tx_done, budget);

rx_done = stmmac_rx_zc(priv, budget, chan);
@@ -5641,6 +5648,10 @@ static int stmmac_napi_poll_rxtx(struct napi_struct *napi, int budget)
spin_unlock_irqrestore(&ch->lock, flags);
}

+ /* TX still have packet to handle, check if we need to arm tx timer */
+ if (tx_pending_packets)
+ stmmac_tx_timer_arm(priv, chan);
+
return min(rxtx_done, budget - 1);
}

--
2.40.1