linux-kernel - [PATCH] kernel: x86: tboot: Replace mdelay with usleep_range in tboot_wait_for

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Date:   Wed, 24 Jan 2018 09:58:22 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     ning.sun@...el.com, tglx@...utronix.de, mingo@...hat.com,
        hpa@...or.com
Cc:     x86@...nel.org, tboot-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] kernel: x86: tboot: Replace mdelay with usleep_range in tboot_wait_for_aps

The function tboot_wait_for_aps is not called in atomic context.
Thus mdelay can be replaced with usleep_range, to reduce busy wait.

Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
---
 arch/x86/kernel/tboot.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index a4eb279..c1d523e 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -317,7 +317,7 @@ static int tboot_wait_for_aps(int num_aps)
 	timeout = AP_WAIT_TIMEOUT*HZ;
 	while (atomic_read((atomic_t *)&tboot->num_in_wfs) != num_aps &&
 	       timeout) {
-		mdelay(1);
+		usleep_range(1000, 2000);
 		timeout--;
 	}
 
-- 
1.7.9.5