From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>,
        Michal Maloszewski <michal.maloszewski@intel.com>,
        Konrad Jankowski <konrad0.jankowski@intel.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>
Subject: [PATCH 5.15 049/171] iavf: Fix reporting when setting descriptor count
Date:   Mon, 13 Dec 2021 10:29:24 +0100
Message-Id: <20211213092946.735890059@linuxfoundation.org>
In-Reply-To: <20211213092945.091487407@linuxfoundation.org>
References: <20211213092945.091487407@linuxfoundation.org>
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From: Michal Maloszewski <michal.maloszewski@intel.com>

commit 1a1aa356ddf3f16539f5962c01c5f702686dfc15 upstream.

iavf_set_ringparams doesn't communicate to the user that

1. The user requested descriptor count is out of range. Instead it
   just quietly sets descriptors to the "clamped" value and calls it
   done. This makes it look an invalid value was successfully set as
   the descriptor count when this isn't actually true.

2. The user provided descriptor count needs to be inflated for alignment
   reasons.

This behavior is confusing. The ice driver has already addressed this
by rejecting invalid values for descriptor count and
messaging for alignment adjustments.
Do the same thing here by adding the error and info messages.

Fixes: fbb7ddfef253 ("i40evf: core ethtool functionality")
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Signed-off-by: Michal Maloszewski <michal.maloszewski@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/intel/iavf/iavf_ethtool.c |   45 ++++++++++++++++++-------
 1 file changed, 33 insertions(+), 12 deletions(-)

--- a/drivers/net/ethernet/intel/iavf/iavf_ethtool.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_ethtool.c
@@ -615,23 +615,44 @@ static int iavf_set_ringparam(struct net
 	if ((ring->rx_mini_pending) || (ring->rx_jumbo_pending))
 		return -EINVAL;
 
-	new_tx_count = clamp_t(u32, ring->tx_pending,
-			       IAVF_MIN_TXD,
-			       IAVF_MAX_TXD);
-	new_tx_count = ALIGN(new_tx_count, IAVF_REQ_DESCRIPTOR_MULTIPLE);
-
-	new_rx_count = clamp_t(u32, ring->rx_pending,
-			       IAVF_MIN_RXD,
-			       IAVF_MAX_RXD);
-	new_rx_count = ALIGN(new_rx_count, IAVF_REQ_DESCRIPTOR_MULTIPLE);
+	if (ring->tx_pending > IAVF_MAX_TXD ||
+	    ring->tx_pending < IAVF_MIN_TXD ||
+	    ring->rx_pending > IAVF_MAX_RXD ||
+	    ring->rx_pending < IAVF_MIN_RXD) {
+		netdev_err(netdev, "Descriptors requested (Tx: %d / Rx: %d) out of range [%d-%d] (increment %d)\n",
+			   ring->tx_pending, ring->rx_pending, IAVF_MIN_TXD,
+			   IAVF_MAX_RXD, IAVF_REQ_DESCRIPTOR_MULTIPLE);
+		return -EINVAL;
+	}
+
+	new_tx_count = ALIGN(ring->tx_pending, IAVF_REQ_DESCRIPTOR_MULTIPLE);
+	if (new_tx_count != ring->tx_pending)
+		netdev_info(netdev, "Requested Tx descriptor count rounded up to %d\n",
+			    new_tx_count);
+
+	new_rx_count = ALIGN(ring->rx_pending, IAVF_REQ_DESCRIPTOR_MULTIPLE);
+	if (new_rx_count != ring->rx_pending)
+		netdev_info(netdev, "Requested Rx descriptor count rounded up to %d\n",
+			    new_rx_count);
 
 	/* if nothing to do return success */
 	if ((new_tx_count == adapter->tx_desc_count) &&
-	    (new_rx_count == adapter->rx_desc_count))
+	    (new_rx_count == adapter->rx_desc_count)) {
+		netdev_dbg(netdev, "Nothing to change, descriptor count is same as requested\n");
 		return 0;
+	}
+
+	if (new_tx_count != adapter->tx_desc_count) {
+		netdev_dbg(netdev, "Changing Tx descriptor count from %d to %d\n",
+			   adapter->tx_desc_count, new_tx_count);
+		adapter->tx_desc_count = new_tx_count;
+	}
 
-	adapter->tx_desc_count = new_tx_count;
-	adapter->rx_desc_count = new_rx_count;
+	if (new_rx_count != adapter->rx_desc_count) {
+		netdev_dbg(netdev, "Changing Rx descriptor count from %d to %d\n",
+			   adapter->rx_desc_count, new_rx_count);
+		adapter->rx_desc_count = new_rx_count;
+	}
 
 	if (netif_running(netdev)) {
 		adapter->flags |= IAVF_FLAG_RESET_NEEDED;