diff mbox series

[net-next,v5,10/11] bnxt_en: Extend queue stop/start for TX rings

Message ID 20250213011240.1640031-11-michael.chan@broadcom.com (mailing list archive)
State Accepted
Commit fe96d717d38ecd8e6e8d710ebf88e82ac35a0032
Delegated to: Netdev Maintainers
Headers show
Series bnxt_en: Add NPAR 1.2 and TPH support | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang success Errors and warnings before: 2 this patch: 2
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 185 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 2 this patch: 2
netdev/source_inline success Was 0 now: 0

Commit Message

Michael Chan Feb. 13, 2025, 1:12 a.m. UTC 
From: Somnath Kotur <somnath.kotur@broadcom.com>

In order to use queue_stop/queue_start to support the new Steering
Tags, we need to free the TX ring and TX completion ring if it is a
combined channel with TX/RX sharing the same NAPI.  Otherwise
TX completions will not have the updated Steering Tag.  If TPH is
not enabled, we just stop the TX ring without freeing the TX/TX cmpl
rings.  With that we can now add napi_disable() and napi_enable()
during queue_stop()/ queue_start().  This will guarantee that NAPI
will stop processing the completion entries in case there are
additional pending entries in the completion rings after queue_stop().

There could be some NQEs sitting unprocessed while NAPI is disabled
thereby leaving the NQ unarmed.  Explicitly re-arm the NQ after
napi_enable() in queue start so that NAPI will resume properly.

Error handling in bnxt_queue_start() requires a reset.  If a TX
ring cannot be allocated or initialized properly, it will cause
TX timeout.  The reset will also free any partially allocated
rings.  We don't expect to hit this error path because re-allocating
previously reserved and allocated rings with the same parameters
should never fail.

Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
---
Cc: David Wei <dw@davidwei.uk>

v5:
Remove reset counter increment.
Add comments about napi_disable().
Add comments that ring alloc should always succed in this code path.

v3:
Fix build bot warning.
Only free TX/TX cmpl rings when TPH is enabled.

v2:
Add reset for error handling in queue_start().
Fix compile error.

Discussion about adding napi_disable()/napi_enable():

https://lore.kernel.org/netdev/5336d624-8d8b-40a6-b732-b020e4a119a2@davidwei.uk/#t
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 119 ++++++++++++++++++++--
 1 file changed, 110 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 2d0d9ac8e2c4..1997cdbd5801 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -11279,6 +11279,78 @@  int bnxt_reserve_rings(struct bnxt *bp, bool irq_re_init)
 	return 0;
 }
 
+static void bnxt_tx_queue_stop(struct bnxt *bp, int idx)
+{
+	struct bnxt_tx_ring_info *txr;
+	struct netdev_queue *txq;
+	struct bnxt_napi *bnapi;
+	int i;
+
+	bnapi = bp->bnapi[idx];
+	bnxt_for_each_napi_tx(i, bnapi, txr) {
+		WRITE_ONCE(txr->dev_state, BNXT_DEV_STATE_CLOSING);
+		synchronize_net();
+
+		if (!(bnapi->flags & BNXT_NAPI_FLAG_XDP)) {
+			txq = netdev_get_tx_queue(bp->dev, txr->txq_index);
+			if (txq) {
+				__netif_tx_lock_bh(txq);
+				netif_tx_stop_queue(txq);
+				__netif_tx_unlock_bh(txq);
+			}
+		}
+
+		if (!bp->tph_mode)
+			continue;
+
+		bnxt_hwrm_tx_ring_free(bp, txr, true);
+		bnxt_hwrm_cp_ring_free(bp, txr->tx_cpr);
+		bnxt_free_one_tx_ring_skbs(bp, txr, txr->txq_index);
+		bnxt_clear_one_cp_ring(bp, txr->tx_cpr);
+	}
+}
+
+static int bnxt_tx_queue_start(struct bnxt *bp, int idx)
+{
+	struct bnxt_tx_ring_info *txr;
+	struct netdev_queue *txq;
+	struct bnxt_napi *bnapi;
+	int rc, i;
+
+	bnapi = bp->bnapi[idx];
+	/* All rings have been reserved and previously allocated.
+	 * Reallocating with the same parameters should never fail.
+	 */
+	bnxt_for_each_napi_tx(i, bnapi, txr) {
+		if (!bp->tph_mode)
+			goto start_tx;
+
+		rc = bnxt_hwrm_cp_ring_alloc_p5(bp, txr->tx_cpr);
+		if (rc)
+			return rc;
+
+		rc = bnxt_hwrm_tx_ring_alloc(bp, txr, false);
+		if (rc)
+			return rc;
+
+		txr->tx_prod = 0;
+		txr->tx_cons = 0;
+		txr->tx_hw_cons = 0;
+start_tx:
+		WRITE_ONCE(txr->dev_state, 0);
+		synchronize_net();
+
+		if (bnapi->flags & BNXT_NAPI_FLAG_XDP)
+			continue;
+
+		txq = netdev_get_tx_queue(bp->dev, txr->txq_index);
+		if (txq)
+			netif_tx_start_queue(txq);
+	}
+
+	return 0;
+}
+
 static void bnxt_free_irq(struct bnxt *bp)
 {
 	struct bnxt_irq *irq;
@@ -15641,7 +15713,9 @@  static int bnxt_queue_start(struct net_device *dev, void *qmem, int idx)
 {
 	struct bnxt *bp = netdev_priv(dev);
 	struct bnxt_rx_ring_info *rxr, *clone;
+	struct bnxt_cp_ring_info *cpr;
 	struct bnxt_vnic_info *vnic;
+	struct bnxt_napi *bnapi;
 	int i, rc;
 
 	rxr = &bp->rx_ring[idx];
@@ -15659,27 +15733,39 @@  static int bnxt_queue_start(struct net_device *dev, void *qmem, int idx)
 
 	bnxt_copy_rx_ring(bp, rxr, clone);
 
+	bnapi = rxr->bnapi;
+	cpr = &bnapi->cp_ring;
+
 	/* All rings have been reserved and previously allocated.
 	 * Reallocating with the same parameters should never fail.
 	 */
 	rc = bnxt_hwrm_rx_ring_alloc(bp, rxr);
 	if (rc)
-		return rc;
+		goto err_reset;
 
 	if (bp->tph_mode) {
 		rc = bnxt_hwrm_cp_ring_alloc_p5(bp, rxr->rx_cpr);
 		if (rc)
-			goto err_free_hwrm_rx_ring;
+			goto err_reset;
 	}
 
 	rc = bnxt_hwrm_rx_agg_ring_alloc(bp, rxr);
 	if (rc)
-		goto err_free_hwrm_cp_ring;
+		goto err_reset;
 
 	bnxt_db_write(bp, &rxr->rx_db, rxr->rx_prod);
 	if (bp->flags & BNXT_FLAG_AGG_RINGS)
 		bnxt_db_write(bp, &rxr->rx_agg_db, rxr->rx_agg_prod);
 
+	if (bp->flags & BNXT_FLAG_SHARED_RINGS) {
+		rc = bnxt_tx_queue_start(bp, idx);
+		if (rc)
+			goto err_reset;
+	}
+
+	napi_enable(&bnapi->napi);
+	bnxt_db_nq_arm(bp, &cpr->cp_db, cpr->cp_raw_cons);
+
 	for (i = 0; i <= BNXT_VNIC_NTUPLE; i++) {
 		vnic = &bp->vnic_info[i];
 
@@ -15696,11 +15782,12 @@  static int bnxt_queue_start(struct net_device *dev, void *qmem, int idx)
 
 	return 0;
 
-err_free_hwrm_cp_ring:
-	if (bp->tph_mode)
-		bnxt_hwrm_cp_ring_free(bp, rxr->rx_cpr);
-err_free_hwrm_rx_ring:
-	bnxt_hwrm_rx_ring_free(bp, rxr, false);
+err_reset:
+	netdev_err(bp->dev, "Unexpected HWRM error during queue start rc: %d\n",
+		   rc);
+	napi_enable(&bnapi->napi);
+	bnxt_db_nq_arm(bp, &cpr->cp_db, cpr->cp_raw_cons);
+	bnxt_reset_task(bp, true);
 	return rc;
 }
 
@@ -15708,7 +15795,9 @@  static int bnxt_queue_stop(struct net_device *dev, void *qmem, int idx)
 {
 	struct bnxt *bp = netdev_priv(dev);
 	struct bnxt_rx_ring_info *rxr;
+	struct bnxt_cp_ring_info *cpr;
 	struct bnxt_vnic_info *vnic;
+	struct bnxt_napi *bnapi;
 	int i;
 
 	for (i = 0; i <= BNXT_VNIC_NTUPLE; i++) {
@@ -15720,17 +15809,29 @@  static int bnxt_queue_stop(struct net_device *dev, void *qmem, int idx)
 	/* Make sure NAPI sees that the VNIC is disabled */
 	synchronize_net();
 	rxr = &bp->rx_ring[idx];
-	cancel_work_sync(&rxr->bnapi->cp_ring.dim.work);
+	bnapi = rxr->bnapi;
+	cpr = &bnapi->cp_ring;
+	cancel_work_sync(&cpr->dim.work);
 	bnxt_hwrm_rx_ring_free(bp, rxr, false);
 	bnxt_hwrm_rx_agg_ring_free(bp, rxr, false);
 	page_pool_disable_direct_recycling(rxr->page_pool);
 	if (bnxt_separate_head_pool())
 		page_pool_disable_direct_recycling(rxr->head_pool);
 
+	if (bp->flags & BNXT_FLAG_SHARED_RINGS)
+		bnxt_tx_queue_stop(bp, idx);
+
+	/* Disable NAPI now after freeing the rings because HWRM_RING_FREE
+	 * completion is handled in NAPI to guarantee no more DMA on that ring
+	 * after seeing the completion.
+	 */
+	napi_disable(&bnapi->napi);
+
 	if (bp->tph_mode) {
 		bnxt_hwrm_cp_ring_free(bp, rxr->rx_cpr);
 		bnxt_clear_one_cp_ring(bp, rxr->rx_cpr);
 	}
+	bnxt_db_nq(bp, &cpr->cp_db, cpr->cp_raw_cons);
 
 	memcpy(qmem, rxr, sizeof(*rxr));
 	bnxt_init_rx_ring_struct(bp, qmem);