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From: Leonardo Bras <leonardo@linux.ibm.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Leonardo Bras <leonardo@linux.ibm.com>,
	Allison Randal <allison@lohutok.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH 1/1] ppc/smp: Replace unnecessary 'while' by 'if'
Date: Thu, 26 Mar 2020 17:37:52 -0300	[thread overview]
Message-ID: <20200326203752.497029-1-leonardo@linux.ibm.com> (raw)

spin_until_cond() will wait until nmi_ipi_busy == false, and
nmi_ipi_lock_start() does not seem to change nmi_ipi_busy, so there is
no way this while will ever repeat.

Replace this 'while' by an 'if', so it does not look like it can repeat.

Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
---
 arch/powerpc/kernel/smp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index ea6adbf6a221..7c904d6fb4d2 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -473,7 +473,7 @@ static int __smp_send_nmi_ipi(int cpu, void (*fn)(struct pt_regs *),
 		return 0;
 
 	nmi_ipi_lock_start(&flags);
-	while (nmi_ipi_busy) {
+	if (nmi_ipi_busy) {
 		nmi_ipi_unlock_end(&flags);
 		spin_until_cond(!nmi_ipi_busy);
 		nmi_ipi_lock_start(&flags);
-- 
2.24.1


             reply	other threads:[~2020-03-26 20:41 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-26 20:37 Leonardo Bras [this message]
2020-03-26 21:40 ` [RFC PATCH 1/1] ppc/smp: Replace unnecessary 'while' by 'if' Paul Mackerras
2020-03-26 22:05   ` Leonardo Bras

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