[PATCH v2 1/4] net/gve: fix DQO descriptor cleaning loop bound

[Tathagat Priyadarshi <tathagat.dpdk@gmail.com>]

In gve_tx_clean_descs_dqo(), the loop condition "while (--nb_descs)"
causes an off-by-one error:
- When nb_descs == 1, --nb_descs decrements to 0 on the first check,
  executing 0 iterations instead of 1.
- When nb_descs == 0, --nb_descs underflows uint16_t to 65535,
  executing 65535 iterations.

Change the condition to "while (nb_descs--)" so that exactly nb_descs
iterations are executed for any input value.

Additionally, in gve_tx_clean_dqo(), handle unrecognized completion
types by breaking from the switch rather than returning immediately,
allowing complq_tail to advance past unknown descriptors rather than
stalling the completion ring at the same entry.

Fixes: 4022f9999f56 ("net/gve: support basic Tx data path for DQO")
Cc: stable@dpdk.org

Signed-off-by: Tathagat Priyadarshi <tathagat.dpdk@gmail.com>
Acked-by: Joshua Washington <joshwash@google.com>
---
 drivers/net/gve/gve_tx_dqo.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/gve/gve_tx_dqo.c b/drivers/net/gve/gve_tx_dqo.c
index 5c03d3d1a2..c864d722d9 100644
--- a/drivers/net/gve/gve_tx_dqo.c
+++ b/drivers/net/gve/gve_tx_dqo.c
@@ -108,8 +108,8 @@ gve_tx_clean_dqo(struct gve_tx_queue *txq)
 		PMD_DRV_DP_LOG(DEBUG, "GVE_COMPL_TYPE_DQO_MISS ignored !!!");
 		break;
 	default:
-		PMD_DRV_DP_LOG(ERR, "unknown completion type.");
-		return;
+		PMD_DRV_DP_LOG(ERR, "unknown completion type %u", compl_desc->type);
+		break;
 	}
 
 	next++;
@@ -122,7 +122,7 @@ gve_tx_clean_dqo(struct gve_tx_queue *txq)
 
 static inline void
 gve_tx_clean_descs_dqo(struct gve_tx_queue *txq, uint16_t nb_descs) {
-	while (--nb_descs)
+	while (nb_descs--)
 		gve_tx_clean_dqo(txq);
 }
 
-- 
2.43.0