iommu/exynos: Change rwlock to spinlock

Since acquiring read_lock is not more frequent than write_lock, it is
not beneficial to use rwlock, this commit changes rwlock to spinlock.

Reviewed-by: Grant Grundler <grundler@chromium.org>
Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

1 files changed, 14 insertions, 13 deletions

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index c1be65fd0af5..d89ad5f8747c 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -164,7 +164,7 @@ struct sysmmu_drvdata {
         struct clk *clk;
         struct clk *clk_master;
         int activations;
-        rwlock_t lock;
+        spinlock_t lock;
         struct iommu_domain *domain;
         phys_addr_t pgtable;
 };
@@ -263,12 +263,13 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
         unsigned long addr = -1;
         int ret = -ENOSYS;
 
-        read_lock(&data->lock);
-
         WARN_ON(!is_sysmmu_active(data));
 
+        spin_lock(&data->lock);
+
         if (!IS_ERR(data->clk_master))
                 clk_enable(data->clk_master);
+
         itype = (enum exynos_sysmmu_inttype)
                 __ffs(__raw_readl(data->sfrbase + REG_INT_STATUS));
         if (WARN_ON(!((itype >= 0) && (itype < SYSMMU_FAULT_UNKNOWN))))
@@ -302,7 +303,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
         if (!IS_ERR(data->clk_master))
                 clk_disable(data->clk_master);
 
-        read_unlock(&data->lock);
+        spin_unlock(&data->lock);
 
         return IRQ_HANDLED;
 }
@@ -312,7 +313,7 @@ static bool __exynos_sysmmu_disable(struct sysmmu_drvdata *data)
         unsigned long flags;
         bool disabled = false;
 
-        write_lock_irqsave(&data->lock, flags);
+        spin_lock_irqsave(&data->lock, flags);
 
         if (!set_sysmmu_inactive(data))
                 goto finish;
@@ -330,7 +331,7 @@ static bool __exynos_sysmmu_disable(struct sysmmu_drvdata *data)
         data->pgtable = 0;
         data->domain = NULL;
 finish:
-        write_unlock_irqrestore(&data->lock, flags);
+        spin_unlock_irqrestore(&data->lock, flags);
 
         if (disabled)
                 dev_dbg(data->sysmmu, "Disabled\n");
@@ -353,7 +354,7 @@ static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
         int ret = 0;
         unsigned long flags;
 
-        write_lock_irqsave(&data->lock, flags);
+        spin_lock_irqsave(&data->lock, flags);
 
         if (!set_sysmmu_active(data)) {
                 if (WARN_ON(pgtable != data->pgtable)) {
@@ -384,7 +385,7 @@ static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
 
         dev_dbg(data->sysmmu, "Enabled\n");
 finish:
-        write_unlock_irqrestore(&data->lock, flags);
+        spin_unlock_irqrestore(&data->lock, flags);
 
         return ret;
 }
@@ -431,7 +432,7 @@ static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova,
         unsigned long flags;
         struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
 
-        read_lock_irqsave(&data->lock, flags);
+        spin_lock_irqsave(&data->lock, flags);
 
         if (is_sysmmu_active(data)) {
                 unsigned int maj;
@@ -465,7 +466,7 @@ static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova,
                 dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
         }
 
-        read_unlock_irqrestore(&data->lock, flags);
+        spin_unlock_irqrestore(&data->lock, flags);
 }
 
 void exynos_sysmmu_tlb_invalidate(struct device *dev)
@@ -473,7 +474,7 @@ void exynos_sysmmu_tlb_invalidate(struct device *dev)
         unsigned long flags;
         struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
 
-        read_lock_irqsave(&data->lock, flags);
+        spin_lock_irqsave(&data->lock, flags);
 
         if (is_sysmmu_active(data)) {
                 if (!IS_ERR(data->clk_master))
@@ -488,7 +489,7 @@ void exynos_sysmmu_tlb_invalidate(struct device *dev)
                 dev_dbg(data->sysmmu, "Disabled. Skipping invalidating TLB.\n");
         }
 
-        read_unlock_irqrestore(&data->lock, flags);
+        spin_unlock_irqrestore(&data->lock, flags);
 }
 
 static int exynos_sysmmu_probe(struct platform_device *pdev)
@@ -543,7 +544,7 @@ static int exynos_sysmmu_probe(struct platform_device *pdev)
         }
 
         data->sysmmu = dev;
-        rwlock_init(&data->lock);
+        spin_lock_init(&data->lock);
         INIT_LIST_HEAD(&data->node);
 
         platform_set_drvdata(pdev, data);