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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Justin Chen <justinpopo6@gmail.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        linux-mips@linux-mips.org, James Hogan <jhogan@kernel.org>
Subject: [PATCH 4.4 13/63] MIPS: BMIPS: Do not mask IPIs during suspend
Date:   Fri, 16 Mar 2018 16:22:45 +0100
Message-Id: <20180316152301.507392406@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Justin Chen <justinpopo6@gmail.com>

commit 06a3f0c9f2725f5d7c63c4203839373c9bd00c28 upstream.

Commit a3e6c1eff548 ("MIPS: IRQ: Fix disable_irq on CPU IRQs") fixes an
issue where disable_irq did not actually disable the irq. The bug caused
our IPIs to not be disabled, which actually is the correct behavior.

With the addition of commit a3e6c1eff548 ("MIPS: IRQ: Fix disable_irq on
CPU IRQs"), the IPIs were getting disabled going into suspend, thus
schedule_ipi() was not being called. This caused deadlocks where
schedulable task were not being scheduled and other cpus were waiting
for them to do something.

Add the IRQF_NO_SUSPEND flag so an irq_disable will not be called on the
IPIs during suspend.

Signed-off-by: Justin Chen <justinpopo6@gmail.com>
Fixes: a3e6c1eff548 ("MIPS: IRQ: Fix disabled_irq on CPU IRQs")
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17385/
[jhogan@kernel.org: checkpatch: wrap long lines and fix commit refs]
Signed-off-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/mips/kernel/smp-bmips.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/arch/mips/kernel/smp-bmips.c
+++ b/arch/mips/kernel/smp-bmips.c
@@ -166,11 +166,11 @@ static void bmips_prepare_cpus(unsigned
 		return;
 	}
 
-	if (request_irq(IPI0_IRQ, bmips_ipi_interrupt, IRQF_PERCPU,
-			"smp_ipi0", NULL))
+	if (request_irq(IPI0_IRQ, bmips_ipi_interrupt,
+			IRQF_PERCPU | IRQF_NO_SUSPEND, "smp_ipi0", NULL))
 		panic("Can't request IPI0 interrupt");
-	if (request_irq(IPI1_IRQ, bmips_ipi_interrupt, IRQF_PERCPU,
-			"smp_ipi1", NULL))
+	if (request_irq(IPI1_IRQ, bmips_ipi_interrupt,
+			IRQF_PERCPU | IRQF_NO_SUSPEND, "smp_ipi1", NULL))
 		panic("Can't request IPI1 interrupt");
 }