netdev - [PATCH net-next 2/2] selftests: drv-net: fix RPS mask handling for high CPU numbers

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Message-ID: <20260111171658.179286-3-gal@nvidia.com>
Date: Sun, 11 Jan 2026 19:16:58 +0200
From: Gal Pressman <gal@...dia.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
	<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
	<pabeni@...hat.com>, Andrew Lunn <andrew+netdev@...n.ch>,
	<netdev@...r.kernel.org>
CC: Shuah Khan <shuah@...nel.org>, Willem de Bruijn <willemb@...gle.com>,
	"Petr Machata" <petrm@...dia.com>, Coco Li <lixiaoyan@...gle.com>,
	<linux-kselftest@...r.kernel.org>, Gal Pressman <gal@...dia.com>, Nimrod Oren
	<noren@...dia.com>
Subject: [PATCH net-next 2/2] selftests: drv-net: fix RPS mask handling for high CPU numbers

The RPS bitmask bounds check uses ~(RPS_MAX_CPUS - 1) which equals ~15 =
0xfff0, only allowing CPUs 0-3.

Change the mask to ~((1UL << RPS_MAX_CPUS) - 1) = ~0xffff to allow CPUs
0-15.

Fixes: 5ebfb4cc3048 ("selftests/net: toeplitz test")
Reviewed-by: Nimrod Oren <noren@...dia.com>
Signed-off-by: Gal Pressman <gal@...dia.com>
---
 tools/testing/selftests/drivers/net/hw/toeplitz.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/drivers/net/hw/toeplitz.c b/tools/testing/selftests/drivers/net/hw/toeplitz.c
index d23b3b0c20a3..285bb17df9c2 100644
--- a/tools/testing/selftests/drivers/net/hw/toeplitz.c
+++ b/tools/testing/selftests/drivers/net/hw/toeplitz.c
@@ -485,8 +485,8 @@ static void parse_rps_bitmap(const char *arg)
 
 	bitmap = strtoul(arg, NULL, 0);
 
-	if (bitmap & ~(RPS_MAX_CPUS - 1))
-		error(1, 0, "rps bitmap 0x%lx out of bounds 0..%lu",
+	if (bitmap & ~((1UL << RPS_MAX_CPUS) - 1))
+		error(1, 0, "rps bitmap 0x%lx out of bounds, max cpu %lu",
 		      bitmap, RPS_MAX_CPUS - 1);
 
 	for (i = 0; i < RPS_MAX_CPUS; i++)
-- 
2.40.1