kernel: cake: backport unused var patch to 5.4

This was backported to 4.19 and I clearly expected it to land in 5.4 but
it didn't (5.5) so backport it to 5.4 for consistency.

Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>

target/linux/generic/backport-5.4/393-v5.5-sch_cake-drop-unused-variable-tin_quantum_prio.patch

@@ -0,0 +1,158 @@
+From d7e1738f0a0b0573ac93cf570ba3df9dee61b68e Mon Sep 17 00:00:00 2001
+From: Kevin 'ldir' Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+Date: Wed, 18 Dec 2019 14:05:13 +0000
+Subject: [PATCH 2/2] sch_cake: drop unused variable tin_quantum_prio
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Turns out tin_quantum_prio isn't used anymore and is a leftover from a
+previous implementation of diffserv tins.  Since the variable isn't used
+in any calculations it can be eliminated.
+
+Drop variable and places where it was set.  Rename remaining variable
+and consolidate naming of intermediate variables that set it.
+
+Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
+Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ net/sched/sch_cake.c | 59 ++++++++++++++------------------------------
+ 1 file changed, 18 insertions(+), 41 deletions(-)
+
+--- a/net/sched/sch_cake.c
++++ b/net/sched/sch_cake.c
+@@ -173,8 +173,7 @@ struct cake_tin_data {
+ 	u64	tin_rate_bps;
+ 	u16	tin_rate_shft;
+ 
+-	u16	tin_quantum_prio;
+-	u16	tin_quantum_band;
++	u16	tin_quantum;
+ 	s32	tin_deficit;
+ 	u32	tin_backlog;
+ 	u32	tin_dropped;
+@@ -1916,7 +1915,7 @@ begin:
+ 		while (b->tin_deficit < 0 ||
+ 		       !(b->sparse_flow_count + b->bulk_flow_count)) {
+ 			if (b->tin_deficit <= 0)
+-				b->tin_deficit += b->tin_quantum_band;
++				b->tin_deficit += b->tin_quantum;
+ 			if (b->sparse_flow_count + b->bulk_flow_count)
+ 				empty = false;
+ 
+@@ -2237,8 +2236,7 @@ static int cake_config_besteffort(struct
+ 
+ 	cake_set_rate(b, rate, mtu,
+ 		      us_to_ns(q->target), us_to_ns(q->interval));
+-	b->tin_quantum_band = 65535;
+-	b->tin_quantum_prio = 65535;
++	b->tin_quantum = 65535;
+ 
+ 	return 0;
+ }
+@@ -2249,8 +2247,7 @@ static int cake_config_precedence(struct
+ 	struct cake_sched_data *q = qdisc_priv(sch);
+ 	u32 mtu = psched_mtu(qdisc_dev(sch));
+ 	u64 rate = q->rate_bps;
+-	u32 quantum1 = 256;
+-	u32 quantum2 = 256;
++	u32 quantum = 256;
+ 	u32 i;
+ 
+ 	q->tin_cnt = 8;
+@@ -2263,18 +2260,14 @@ static int cake_config_precedence(struct
+ 		cake_set_rate(b, rate, mtu, us_to_ns(q->target),
+ 			      us_to_ns(q->interval));
+ 
+-		b->tin_quantum_prio = max_t(u16, 1U, quantum1);
+-		b->tin_quantum_band = max_t(u16, 1U, quantum2);
++		b->tin_quantum = max_t(u16, 1U, quantum);
+ 
+ 		/* calculate next class's parameters */
+ 		rate  *= 7;
+ 		rate >>= 3;
+ 
+-		quantum1  *= 3;
+-		quantum1 >>= 1;
+-
+-		quantum2  *= 7;
+-		quantum2 >>= 3;
++		quantum  *= 7;
++		quantum >>= 3;
+ 	}
+ 
+ 	return 0;
+@@ -2343,8 +2336,7 @@ static int cake_config_diffserv8(struct
+ 	struct cake_sched_data *q = qdisc_priv(sch);
+ 	u32 mtu = psched_mtu(qdisc_dev(sch));
+ 	u64 rate = q->rate_bps;
+-	u32 quantum1 = 256;
+-	u32 quantum2 = 256;
++	u32 quantum = 256;
+ 	u32 i;
+ 
+ 	q->tin_cnt = 8;
+@@ -2360,18 +2352,14 @@ static int cake_config_diffserv8(struct
+ 		cake_set_rate(b, rate, mtu, us_to_ns(q->target),
+ 			      us_to_ns(q->interval));
+ 
+-		b->tin_quantum_prio = max_t(u16, 1U, quantum1);
+-		b->tin_quantum_band = max_t(u16, 1U, quantum2);
++		b->tin_quantum = max_t(u16, 1U, quantum);
+ 
+ 		/* calculate next class's parameters */
+ 		rate  *= 7;
+ 		rate >>= 3;
+ 
+-		quantum1  *= 3;
+-		quantum1 >>= 1;
+-
+-		quantum2  *= 7;
+-		quantum2 >>= 3;
++		quantum  *= 7;
++		quantum >>= 3;
+ 	}
+ 
+ 	return 0;
+@@ -2410,17 +2398,11 @@ static int cake_config_diffserv4(struct
+ 	cake_set_rate(&q->tins[3], rate >> 2, mtu,
+ 		      us_to_ns(q->target), us_to_ns(q->interval));
+ 
+-	/* priority weights */
+-	q->tins[0].tin_quantum_prio = quantum;
+-	q->tins[1].tin_quantum_prio = quantum >> 4;
+-	q->tins[2].tin_quantum_prio = quantum << 2;
+-	q->tins[3].tin_quantum_prio = quantum << 4;
+-
+ 	/* bandwidth-sharing weights */
+-	q->tins[0].tin_quantum_band = quantum;
+-	q->tins[1].tin_quantum_band = quantum >> 4;
+-	q->tins[2].tin_quantum_band = quantum >> 1;
+-	q->tins[3].tin_quantum_band = quantum >> 2;
++	q->tins[0].tin_quantum = quantum;
++	q->tins[1].tin_quantum = quantum >> 4;
++	q->tins[2].tin_quantum = quantum >> 1;
++	q->tins[3].tin_quantum = quantum >> 2;
+ 
+ 	return 0;
+ }
+@@ -2451,15 +2433,10 @@ static int cake_config_diffserv3(struct
+ 	cake_set_rate(&q->tins[2], rate >> 2, mtu,
+ 		      us_to_ns(q->target), us_to_ns(q->interval));
+ 
+-	/* priority weights */
+-	q->tins[0].tin_quantum_prio = quantum;
+-	q->tins[1].tin_quantum_prio = quantum >> 4;
+-	q->tins[2].tin_quantum_prio = quantum << 4;
+-
+ 	/* bandwidth-sharing weights */
+-	q->tins[0].tin_quantum_band = quantum;
+-	q->tins[1].tin_quantum_band = quantum >> 4;
+-	q->tins[2].tin_quantum_band = quantum >> 2;
++	q->tins[0].tin_quantum = quantum;
++	q->tins[1].tin_quantum = quantum >> 4;
++	q->tins[2].tin_quantum = quantum >> 2;
+ 
+ 	return 0;
+ }