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>

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index c1be65f..d89ad5f 100644 (file)
--- 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);