[PATCH] net: ieee8021q: fix insufficient table-size assertion

[PATCH] net: ieee8021q: fix insufficient table-size assertion

[RubenKelevra]

_Static_assert(ARRAY_SIZE(map) != IEEE8021Q_TT_MAX - 1) rejects only a
length of 7 and allows any other mismatch. Replace it with a strict
equality test via a helper macro so that every mapping table must have
exactly IEEE8021Q_TT_MAX (8) entries.

Signed-off-by: RubenKelevra <rubenkelevra@gmail.com>
---
 net/core/ieee8021q_helpers.c | 44 +++++++++++-------------------------
 1 file changed, 13 insertions(+), 31 deletions(-)

diff --git a/net/core/ieee8021q_helpers.c b/net/core/ieee8021q_helpers.c
index 759a9b9f3f898..669b357b73b2d 100644
--- a/net/core/ieee8021q_helpers.c
+++ b/net/core/ieee8021q_helpers.c
@@ -7,6 +7,11 @@
 #include <net/dscp.h>
 #include <net/ieee8021q.h>
 
+/* verify that table covers all 8 traffic types */
+#define TT_MAP_SIZE_OK(tbl)                                 \
+	compiletime_assert(ARRAY_SIZE(tbl) == IEEE8021Q_TT_MAX, \
+			   #tbl " size mismatch")
+
 /* The following arrays map Traffic Types (TT) to traffic classes (TC) for
  * different number of queues as shown in the example provided by
  * IEEE 802.1Q-2022 in Annex I "I.3 Traffic type to traffic class mapping" and
@@ -101,51 +106,28 @@ int ieee8021q_tt_to_tc(enum ieee8021q_traffic_type tt, unsigned int num_queues)
 
 	switch (num_queues) {
 	case 8:
-		compiletime_assert(ARRAY_SIZE(ieee8021q_8queue_tt_tc_map) !=
-				   IEEE8021Q_TT_MAX - 1,
-				   "ieee8021q_8queue_tt_tc_map != max - 1");
+		TT_MAP_SIZE_OK(ieee8021q_8queue_tt_tc_map);
 		return ieee8021q_8queue_tt_tc_map[tt];
 	case 7:
-		compiletime_assert(ARRAY_SIZE(ieee8021q_7queue_tt_tc_map) !=
-				   IEEE8021Q_TT_MAX - 1,
-				   "ieee8021q_7queue_tt_tc_map != max - 1");
-
+		TT_MAP_SIZE_OK(ieee8021q_7queue_tt_tc_map);
 		return ieee8021q_7queue_tt_tc_map[tt];
 	case 6:
-		compiletime_assert(ARRAY_SIZE(ieee8021q_6queue_tt_tc_map) !=
-				   IEEE8021Q_TT_MAX - 1,
-				   "ieee8021q_6queue_tt_tc_map != max - 1");
-
+		TT_MAP_SIZE_OK(ieee8021q_6queue_tt_tc_map);
 		return ieee8021q_6queue_tt_tc_map[tt];
 	case 5:
-		compiletime_assert(ARRAY_SIZE(ieee8021q_5queue_tt_tc_map) !=
-				   IEEE8021Q_TT_MAX - 1,
-				   "ieee8021q_5queue_tt_tc_map != max - 1");
-
+		TT_MAP_SIZE_OK(ieee8021q_5queue_tt_tc_map);
 		return ieee8021q_5queue_tt_tc_map[tt];
 	case 4:
-		compiletime_assert(ARRAY_SIZE(ieee8021q_4queue_tt_tc_map) !=
-				   IEEE8021Q_TT_MAX - 1,
-				   "ieee8021q_4queue_tt_tc_map != max - 1");
-
+		TT_MAP_SIZE_OK(ieee8021q_4queue_tt_tc_map);
 		return ieee8021q_4queue_tt_tc_map[tt];
 	case 3:
-		compiletime_assert(ARRAY_SIZE(ieee8021q_3queue_tt_tc_map) !=
-				   IEEE8021Q_TT_MAX - 1,
-				   "ieee8021q_3queue_tt_tc_map != max - 1");
-
+		TT_MAP_SIZE_OK(ieee8021q_3queue_tt_tc_map);
 		return ieee8021q_3queue_tt_tc_map[tt];
 	case 2:
-		compiletime_assert(ARRAY_SIZE(ieee8021q_2queue_tt_tc_map) !=
-				   IEEE8021Q_TT_MAX - 1,
-				   "ieee8021q_2queue_tt_tc_map != max - 1");
-
+		TT_MAP_SIZE_OK(ieee8021q_2queue_tt_tc_map);
 		return ieee8021q_2queue_tt_tc_map[tt];
 	case 1:
-		compiletime_assert(ARRAY_SIZE(ieee8021q_1queue_tt_tc_map) !=
-				   IEEE8021Q_TT_MAX - 1,
-				   "ieee8021q_1queue_tt_tc_map != max - 1");
-
+		TT_MAP_SIZE_OK(ieee8021q_1queue_tt_tc_map);
 		return ieee8021q_1queue_tt_tc_map[tt];
 	}
 
-- 
2.50.0

Re: [PATCH] net: ieee8021q: fix insufficient table-size assertion

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Thu, 26 Jun 2025 22:59:07 +0200 you wrote:
> _Static_assert(ARRAY_SIZE(map) != IEEE8021Q_TT_MAX - 1) rejects only a
> length of 7 and allows any other mismatch. Replace it with a strict
> equality test via a helper macro so that every mapping table must have
> exactly IEEE8021Q_TT_MAX (8) entries.
> 
> Signed-off-by: RubenKelevra <rubenkelevra@gmail.com>
> 
> [...]

Here is the summary with links:
  - net: ieee8021q: fix insufficient table-size assertion
    https://git.kernel.org/netdev/net-next/c/21deb2d96692

You are awesome, thank you!
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