Subject: [RFC PATCH net-next v2 2/6] net: xilinx: axienet: Report an error for bad coalesce settings

From: Sean Anderson <[email-masked]>
Date: Mon, 9 Sep 2024 19:52:04 -0400

Instead of silently ignoring invalid/unsupported settings, report an
error. Additionally, relax the check for non-zero usecs to apply only
when it will be used (i.e. when frames != 1).

Signed-off-by: Sean Anderson <[email-masked]>
---

Changes in v2:
- New

 .../net/ethernet/xilinx/xilinx_axienet_main.c | 27 +++++++++++++------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index cf67d455da48..bc987f7ca1ea 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -2048,14 +2048,25 @@ axienet_ethtools_set_coalesce(struct net_device *ndev,
 		return -EBUSY;
 	}
 
-	if (ecoalesce->rx_max_coalesced_frames)
-		lp->coalesce_count_rx = ecoalesce->rx_max_coalesced_frames;
-	if (ecoalesce->rx_coalesce_usecs)
-		lp->coalesce_usec_rx = ecoalesce->rx_coalesce_usecs;
-	if (ecoalesce->tx_max_coalesced_frames)
-		lp->coalesce_count_tx = ecoalesce->tx_max_coalesced_frames;
-	if (ecoalesce->tx_coalesce_usecs)
-		lp->coalesce_usec_tx = ecoalesce->tx_coalesce_usecs;
+	if (!ecoalesce->rx_max_coalesced_frames ||
+	    !ecoalesce->tx_max_coalesced_frames) {
+		NL_SET_ERR_MSG(extack, "frames must be non-zero");
+		return -EINVAL;
+	}
+
+	if ((ecoalesce->rx_max_coalesced_frames > 1 &&
+	     !ecoalesce->rx_coalesce_usecs) ||
+	    (ecoalesce->tx_max_coalesced_frames > 1 &&
+	     !ecoalesce->tx_coalesce_usecs)) {
+		NL_SET_ERR_MSG(extack,
+			       "usecs must be non-zero when frames is greater than one");
+		return -EINVAL;
+	}
+
+	lp->coalesce_count_rx = ecoalesce->rx_max_coalesced_frames;
+	lp->coalesce_usec_rx = ecoalesce->rx_coalesce_usecs;
+	lp->coalesce_count_tx = ecoalesce->tx_max_coalesced_frames;
+	lp->coalesce_usec_tx = ecoalesce->tx_coalesce_usecs;
 
 	return 0;
 }
-- 
2.35.1.1320.gc452695387.dirty