linux-kernel - [PATCH] mips: Fix using smp_processor

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Date:   Wed,  9 Aug 2017 16:25:50 -0500
From:   minyard@....org
To:     linux-mips@...ux-mips.org, ralf@...ux-mips.org,
        linux-kernel@...r.kernel.org
Cc:     Corey Minyard <cminyard@...sta.com>
Subject: [PATCH] mips: Fix using smp_processor_id() when preemptible

From: Corey Minyard <cminyard@...sta.com>

I was getting the following:

BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1
caller is pcibios_set_cache_line_size+0x10/0x58

pcibios_set_cache_line_size() used current_cpu_data outside of
an unpreemptible context.

Signed-off-by: Corey Minyard <cminyard@...sta.com>
---
 arch/mips/pci/pci.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c
index bd67ac7..afd2f8a 100644
--- a/arch/mips/pci/pci.c
+++ b/arch/mips/pci/pci.c
@@ -28,9 +28,11 @@ EXPORT_SYMBOL(PCIBIOS_MIN_MEM);
 
 static int __init pcibios_set_cache_line_size(void)
 {
-	struct cpuinfo_mips *c = &current_cpu_data;
+	struct cpuinfo_mips *c;
 	unsigned int lsize;
 
+	preempt_disable();
+	c = &current_cpu_data;
 	/*
 	 * Set PCI cacheline size to that of the highest level in the
 	 * cache hierarchy.
@@ -38,6 +40,7 @@ static int __init pcibios_set_cache_line_size(void)
 	lsize = c->dcache.linesz;
 	lsize = c->scache.linesz ? : lsize;
 	lsize = c->tcache.linesz ? : lsize;
+	preempt_enable();
 
 	BUG_ON(!lsize);
 
-- 
2.7.4