linux-kernel - [PATCH] powerpc/kernel: Avoid preemption check during iommu_range

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Message-Id: <20170720172606.3811-1-victora@linux.vnet.ibm.com>
Date:   Thu, 20 Jul 2017 14:26:06 -0300
From:   Victor Aoqui <victora@...ux.vnet.ibm.com>
To:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        aneesh.kumar@...ux.vnet.ibm.com, mpe@...erman.id.au,
        khandual@...ux.vnet.ibm.com
Cc:     victora@...ibm.com, victora@...ux.vnet.ibm.com,
        mauricfo@...ux.vnet.ibm.com
Subject: [PATCH] powerpc/kernel: Avoid preemption check during iommu_range_alloc

Replaced __this_cpu_read function call by raw_cpu_read in
iommu_range_alloc function.
Preemption doesn't need to be disabled since any CPU can safely
use IOMMU pool.

Signed-off-by: Victor Aoqui <victora@...ux.vnet.ibm.com>
---
 arch/powerpc/kernel/iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 233ca3f..0e49a45 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -208,7 +208,7 @@ static unsigned long iommu_range_alloc(struct device *dev,
 	 * We don't need to disable preemption here because any CPU can
 	 * safely use any IOMMU pool.
 	 */
-	pool_nr = __this_cpu_read(iommu_pool_hash) & (tbl->nr_pools - 1);
+	pool_nr = raw_cpu_read(iommu_pool_hash) & (tbl->nr_pools - 1);
 
 	if (largealloc)
 		pool = &(tbl->large_pool);
-- 
1.8.3.1