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From:   Yury Norov <yury.norov@gmail.com>
To:     linux-kernel@vger.kernel.org,
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        Yury Norov <yury.norov@gmail.com>, linux-mm@kvack.org,
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Subject: [PATCH 13/16] time: optimize tick_setup_device()
Date:   Mon, 18 Jul 2022 12:28:41 -0700
Message-Id: <20220718192844.1805158-14-yury.norov@gmail.com>
In-Reply-To: <20220718192844.1805158-1-yury.norov@gmail.com>
References: <20220718192844.1805158-1-yury.norov@gmail.com>
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tick_setup_device() calls cpumask_equal(newdev->cpumask, cpumask)
even if newdev->cpumask == cpumask. Fix it.

Caught with CONFIG_DEBUG_BITMAP:
[    0.070960] Call trace:
[    0.070974]  __bitmap_check_params+0x144/0x250
[    0.071008]  tick_setup_device+0x70/0x1a0
[    0.071040]  tick_check_new_device+0xc0/0x110
[    0.071066]  clockevents_register_device+0x74/0x1c0
[    0.071090]  clockevents_config_and_register+0x2c/0x3c
[    0.071114]  arch_timer_starting_cpu+0x170/0x470
[    0.071147]  cpuhp_invoke_callback+0x104/0x20c
[    0.071180]  cpuhp_invoke_callback_range+0x70/0xf0
[    0.071205]  notify_cpu_starting+0xac/0xcc
[    0.071229]  secondary_start_kernel+0xe4/0x154
[    0.071259]  __secondary_switched+0xa0/0xa4
[    0.071297] ---[ end trace 0000000000000000 ]---
[    0.071328] b1:	ffffa1f27323b890
[    0.071339] b2:	ffffa1f27323b890
[    0.071348] b3:	0
[    0.071356] nbits:	256
[    0.071366] start:	0
[    0.071374] off:	0
[    0.071383] Bitmap: parameters check failed
[    0.071390] include/linux/bitmap.h [419]: bitmap_equal

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
 kernel/time/tick-common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 7205f76f8d10..7b2da8ef09ef 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -255,7 +255,7 @@ static void tick_setup_device(struct tick_device *td,
 	 * When the device is not per cpu, pin the interrupt to the
 	 * current cpu:
 	 */
-	if (!cpumask_equal(newdev->cpumask, cpumask))
+	if (newdev->cpumask != cpumask && !cpumask_equal(newdev->cpumask, cpumask))
 		irq_set_affinity(newdev->irq, cpumask);
 
 	/*
-- 
2.34.1