From 2f7c68cb55ecb7331f2381deb497c27155f32faf Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 03 Jan 2024 09:43:39 +0000
Subject: [PATCH] update kernel to 5.10.198

---
 kernel/drivers/net/dsa/sja1105/sja1105_main.c |   38 ++++++++++++++++++++++++++++++++------
 1 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/kernel/drivers/net/dsa/sja1105/sja1105_main.c b/kernel/drivers/net/dsa/sja1105/sja1105_main.c
index c03d76c..4362fe0 100644
--- a/kernel/drivers/net/dsa/sja1105/sja1105_main.c
+++ b/kernel/drivers/net/dsa/sja1105/sja1105_main.c
@@ -1691,6 +1691,18 @@
 
 #define BYTES_PER_KBIT (1000LL / 8)
 
+static int sja1105_find_cbs_shaper(struct sja1105_private *priv,
+				   int port, int prio)
+{
+	int i;
+
+	for (i = 0; i < priv->info->num_cbs_shapers; i++)
+		if (priv->cbs[i].port == port && priv->cbs[i].prio == prio)
+			return i;
+
+	return -1;
+}
+
 static int sja1105_find_unused_cbs_shaper(struct sja1105_private *priv)
 {
 	int i;
@@ -1725,14 +1737,20 @@
 {
 	struct sja1105_private *priv = ds->priv;
 	struct sja1105_cbs_entry *cbs;
+	s64 port_transmit_rate_kbps;
 	int index;
 
 	if (!offload->enable)
 		return sja1105_delete_cbs_shaper(priv, port, offload->queue);
 
-	index = sja1105_find_unused_cbs_shaper(priv);
-	if (index < 0)
-		return -ENOSPC;
+	/* The user may be replacing an existing shaper */
+	index = sja1105_find_cbs_shaper(priv, port, offload->queue);
+	if (index < 0) {
+		/* That isn't the case - see if we can allocate a new one */
+		index = sja1105_find_unused_cbs_shaper(priv);
+		if (index < 0)
+			return -ENOSPC;
+	}
 
 	cbs = &priv->cbs[index];
 	cbs->port = port;
@@ -1742,9 +1760,17 @@
 	 */
 	cbs->credit_hi = offload->hicredit;
 	cbs->credit_lo = abs(offload->locredit);
-	/* User space is in kbits/sec, hardware in bytes/sec */
-	cbs->idle_slope = offload->idleslope * BYTES_PER_KBIT;
-	cbs->send_slope = abs(offload->sendslope * BYTES_PER_KBIT);
+	/* User space is in kbits/sec, while the hardware in bytes/sec times
+	 * link speed. Since the given offload->sendslope is good only for the
+	 * current link speed anyway, and user space is likely to reprogram it
+	 * when that changes, don't even bother to track the port's link speed,
+	 * but deduce the port transmit rate from idleslope - sendslope.
+	 */
+	port_transmit_rate_kbps = offload->idleslope - offload->sendslope;
+	cbs->idle_slope = div_s64(offload->idleslope * BYTES_PER_KBIT,
+				  port_transmit_rate_kbps);
+	cbs->send_slope = div_s64(abs(offload->sendslope * BYTES_PER_KBIT),
+				  port_transmit_rate_kbps);
 	/* Convert the negative values from 64-bit 2's complement
 	 * to 32-bit 2's complement (for the case of 0x80000000 whose
 	 * negative is still negative).

--
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