sch_cake: revise Diffserv docs

Documentation incorrectly stated that CS1 is equivalent to LE for
diffserv8. But when LE was added to the table, CS1 was pushed into tin
1, leaving only LE in tin 0.

Also "TOS1" no longer exists, as that is the same codepoint as LE.

Make other tweaks properly distinguishing codepoints from classes and
putting current Diffserve codepoints ahead of legacy ones.

Signed-off-by: Kevin Bracey <[email protected]>
Acked-by: Toke Høiland-Jørgensen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kjbracey2

net/sched/sch_cake.c

@@ -2342,16 +2342,15 @@ static int cake_config_precedence(struct Qdisc *sch)
 
 /*	List of known Diffserv codepoints:
  *
- *	Least Effort (CS1, LE)
- *	Best Effort (CS0)
- *	Max Reliability & LLT "Lo" (TOS1)
+ *	Default Forwarding (DF/CS0) - Best Effort
  *	Max Throughput (TOS2)
  *	Min Delay (TOS4)
  *	LLT "La" (TOS5)
  *	Assured Forwarding 1 (AF1x) - x3
  *	Assured Forwarding 2 (AF2x) - x3
  *	Assured Forwarding 3 (AF3x) - x3
  *	Assured Forwarding 4 (AF4x) - x3
+ *	Precedence Class 1 (CS1)
  *	Precedence Class 2 (CS2)
  *	Precedence Class 3 (CS3)
  *	Precedence Class 4 (CS4)
@@ -2360,8 +2359,9 @@ static int cake_config_precedence(struct Qdisc *sch)
  *	Precedence Class 7 (CS7)
  *	Voice Admit (VA)
  *	Expedited Forwarding (EF)
-
- *	Total 25 codepoints.
+ *	Lower Effort (LE)
+ *
+ *	Total 26 codepoints.
  */
 
 /*	List of traffic classes in RFC 4594, updated by RFC 8622:
@@ -2375,12 +2375,12 @@ static int cake_config_precedence(struct Qdisc *sch)
  *	Realtime Interactive (CS4)     - eg. games
  *	Multimedia Streaming (AF3x)    - eg. YouTube, NetFlix, Twitch
  *	Broadcast Video (CS3)
- *	Low Latency Data (AF2x,TOS4)      - eg. database
- *	Ops, Admin, Management (CS2,TOS1) - eg. ssh
- *	Standard Service (CS0 & unrecognised codepoints)
- *	High Throughput Data (AF1x,TOS2)  - eg. web traffic
- *	Low Priority Data (CS1,LE)        - eg. BitTorrent
-
+ *	Low-Latency Data (AF2x,TOS4)      - eg. database
+ *	Ops, Admin, Management (CS2)      - eg. ssh
+ *	Standard Service (DF & unrecognised codepoints)
+ *	High-Throughput Data (AF1x,TOS2)  - eg. web traffic
+ *	Low-Priority Data (LE,CS1)        - eg. BitTorrent
+ *
  *	Total 12 traffic classes.
  */
 
@@ -2390,12 +2390,12 @@ static int cake_config_diffserv8(struct Qdisc *sch)
  *
  *		Network Control          (CS6, CS7)
  *		Minimum Latency          (EF, VA, CS5, CS4)
- *		Interactive Shell        (CS2, TOS1)
+ *		Interactive Shell        (CS2)
  *		Low Latency Transactions (AF2x, TOS4)
  *		Video Streaming          (AF4x, AF3x, CS3)
- *		Bog Standard             (CS0 etc.)
- *		High Throughput          (AF1x, TOS2)
- *		Background Traffic       (CS1, LE)
+ *		Bog Standard             (DF etc.)
+ *		High Throughput          (AF1x, TOS2, CS1)
+ *		Background Traffic       (LE)
  *
  *		Total 8 traffic classes.
  */
@@ -2437,9 +2437,9 @@ static int cake_config_diffserv4(struct Qdisc *sch)
 /*  Further pruned list of traffic classes for four-class system:
  *
  *	    Latency Sensitive  (CS7, CS6, EF, VA, CS5, CS4)
- *	    Streaming Media    (AF4x, AF3x, CS3, AF2x, TOS4, CS2, TOS1)
- *	    Best Effort        (CS0, AF1x, TOS2, and those not specified)
- *	    Background Traffic (CS1, LE)
+ *	    Streaming Media    (AF4x, AF3x, CS3, AF2x, TOS4, CS2)
+ *	    Best Effort        (DF, AF1x, TOS2, and those not specified)
+ *	    Background Traffic (LE, CS1)
  *
  *		Total 4 traffic classes.
  */
@@ -2477,9 +2477,9 @@ static int cake_config_diffserv4(struct Qdisc *sch)
 static int cake_config_diffserv3(struct Qdisc *sch)
 {
 /*  Simplified Diffserv structure with 3 tins.
- *		Low Priority		(CS1, LE)
+ *		Latency Sensitive	(CS7, CS6, EF, VA, TOS4)
  *		Best Effort
- *		Latency Sensitive	(TOS4, VA, EF, CS6, CS7)
+ *		Low Priority		(LE, CS1)
  */
 	struct cake_sched_data *q = qdisc_priv(sch);
 	u32 mtu = psched_mtu(qdisc_dev(sch));