2013-07-26 11:30:47

by Cho KyongHo

Subject: [PATCH v8 11/12] 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.

Signed-off-by: Cho KyongHo <[email protected]>
---
drivers/iommu/exynos-iommu.c | 36 ++++++++++++++++++------------------
1 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index c62c244..51e5b35 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -187,7 +187,7 @@ struct sysmmu_drvdata {
struct clk *clk;
struct clk *clk_master;
int activations;
- rwlock_t lock;
+ spinlock_t lock;
struct iommu_domain *domain;
bool runtime_active;
unsigned long pgtable;
@@ -287,7 +287,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
BUG_ON((base0 + size0) <= base0);
BUG_ON((size1 > 0) && ((base1 + size1) <= base1));

- read_lock_irqsave(&data->lock, flags);
+ spin_lock_irqsave(&data->lock, flags);
if (!is_sysmmu_active(data))
goto finish;

@@ -319,7 +319,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
}
clk_disable(data->clk_master);
finish:
- read_unlock_irqrestore(&data->lock, flags);
+ spin_unlock_irqrestore(&data->lock, flags);
}

static void show_fault_information(const char *name,
@@ -371,7 +371,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)

if (client)
spin_lock(&client->lock);
- read_lock(&data->lock);
+ spin_lock(&data->lock);

if (i == data->nsfrs) {
itype = SYSMMU_FAULT_UNKNOWN;
@@ -402,7 +402,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
if (itype != SYSMMU_FAULT_UNKNOWN)
sysmmu_unblock(data->sfrbases[i]);

- read_unlock(&data->lock);
+ spin_unlock(&data->lock);
if (client)
spin_unlock(&client->lock);

@@ -429,7 +429,7 @@ static bool __sysmmu_disable(struct sysmmu_drvdata *data)
bool disabled;
unsigned long flags;

- write_lock_irqsave(&data->lock, flags);
+ spin_lock_irqsave(&data->lock, flags);

disabled = set_sysmmu_inactive(data);

@@ -446,7 +446,7 @@ static bool __sysmmu_disable(struct sysmmu_drvdata *data)
data->activations);
}

- write_unlock_irqrestore(&data->lock, flags);
+ spin_unlock_irqrestore(&data->lock, flags);

return disabled;
}
@@ -493,7 +493,7 @@ static int __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)) {
data->pgtable = pgtable;
data->domain = domain;
@@ -511,7 +511,7 @@ static int __sysmmu_enable(struct sysmmu_drvdata *data,
if (WARN_ON(ret < 0))
set_sysmmu_inactive(data); /* decrement count */

- write_unlock_irqrestore(&data->lock, flags);
+ spin_unlock_irqrestore(&data->lock, flags);

return ret;
}
@@ -602,7 +602,7 @@ static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)

data = dev_get_drvdata(client->sysmmu[i]);

- read_lock_irqsave(&data->lock, flags);
+ spin_lock_irqsave(&data->lock, flags);
if (is_sysmmu_active(data) && data->runtime_active) {
int i;
clk_enable(data->clk_master);
@@ -615,7 +615,7 @@ static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
"disabled. Skipping TLB invalidation @ %#lx\n",
iova);
}
- read_unlock_irqrestore(&data->lock, flags);
+ spin_unlock_irqrestore(&data->lock, flags);
}
}

@@ -630,7 +630,7 @@ void exynos_sysmmu_tlb_invalidate(struct device *dev)

data = dev_get_drvdata(client->sysmmu[i]);

- read_lock_irqsave(&data->lock, flags);
+ spin_lock_irqsave(&data->lock, flags);
if (is_sysmmu_active(data) &&
data->runtime_active) {
int i;
@@ -646,7 +646,7 @@ void exynos_sysmmu_tlb_invalidate(struct device *dev)
} else {
dev_dbg(dev, "disabled. Skipping TLB invalidation\n");
}
- read_unlock_irqrestore(&data->lock, flags);
+ spin_unlock_irqrestore(&data->lock, flags);
}
}

@@ -735,7 +735,7 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)

data->runtime_active = !pm_runtime_enabled(dev);

- rwlock_init(&data->lock);
+ spin_lock_init(&data->lock);
INIT_LIST_HEAD(&data->node);

platform_set_drvdata(pdev, data);
@@ -749,11 +749,11 @@ static int sysmmu_suspend(struct device *dev)
{
struct sysmmu_drvdata *data = dev_get_drvdata(dev);
unsigned long flags;
- read_lock_irqsave(&data->lock, flags);
+ spin_lock_irqsave(&data->lock, flags);
if (is_sysmmu_active(data) &&
(!pm_runtime_enabled(dev) || data->runtime_active))
__sysmmu_disable_nocount(data);
- read_unlock_irqrestore(&data->lock, flags);
+ spin_unlock_irqrestore(&data->lock, flags);
return 0;
}

@@ -761,11 +761,11 @@ static int sysmmu_resume(struct device *dev)
{
struct sysmmu_drvdata *data = dev_get_drvdata(dev);
unsigned long flags;
- read_lock_irqsave(&data->lock, flags);
+ spin_lock_irqsave(&data->lock, flags);
if (is_sysmmu_active(data) &&
(!pm_runtime_enabled(dev) || data->runtime_active))
__sysmmu_enable_nocount(data);
- read_unlock_irqrestore(&data->lock, flags);
+ spin_unlock_irqrestore(&data->lock, flags);
return 0;
}
#endif
--
1.7.2.5

2013-07-26 17:16:53

by Grant Grundler

Subject: Re: [PATCH v8 11/12] iommu/exynos: change rwlock to spinlock

On Fri, Jul 26, 2013 at 4:30 AM, Cho KyongHo <[email protected]> wrote:
> Since acquiring read_lock is not more frequent than write_lock, it is
> not beneficial to use rwlock, this commit changes rwlock to spinlock.
>
> Signed-off-by: Cho KyongHo <[email protected]>

Reviewed-by: Grant Grundler <[email protected]>

cheers,
grant

> ---
> drivers/iommu/exynos-iommu.c | 36 ++++++++++++++++++------------------
> 1 files changed, 18 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> index c62c244..51e5b35 100644
> --- a/drivers/iommu/exynos-iommu.c
> +++ b/drivers/iommu/exynos-iommu.c
> @@ -187,7 +187,7 @@ struct sysmmu_drvdata {
> struct clk *clk;
> struct clk *clk_master;
> int activations;
> - rwlock_t lock;
> + spinlock_t lock;
> struct iommu_domain *domain;
> bool runtime_active;
> unsigned long pgtable;
> @@ -287,7 +287,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
> BUG_ON((base0 + size0) <= base0);
> BUG_ON((size1 > 0) && ((base1 + size1) <= base1));
>
> - read_lock_irqsave(&data->lock, flags);
> + spin_lock_irqsave(&data->lock, flags);
> if (!is_sysmmu_active(data))
> goto finish;
>
> @@ -319,7 +319,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
> }
> clk_disable(data->clk_master);
> finish:
> - read_unlock_irqrestore(&data->lock, flags);
> + spin_unlock_irqrestore(&data->lock, flags);
> }
>
> static void show_fault_information(const char *name,
> @@ -371,7 +371,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
>
> if (client)
> spin_lock(&client->lock);
> - read_lock(&data->lock);
> + spin_lock(&data->lock);
>
> if (i == data->nsfrs) {
> itype = SYSMMU_FAULT_UNKNOWN;
> @@ -402,7 +402,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> if (itype != SYSMMU_FAULT_UNKNOWN)
> sysmmu_unblock(data->sfrbases[i]);
>
> - read_unlock(&data->lock);
> + spin_unlock(&data->lock);
> if (client)
> spin_unlock(&client->lock);
>
> @@ -429,7 +429,7 @@ static bool __sysmmu_disable(struct sysmmu_drvdata *data)
> bool disabled;
> unsigned long flags;
>
> - write_lock_irqsave(&data->lock, flags);
> + spin_lock_irqsave(&data->lock, flags);
>
> disabled = set_sysmmu_inactive(data);
>
> @@ -446,7 +446,7 @@ static bool __sysmmu_disable(struct sysmmu_drvdata *data)
> data->activations);
> }
>
> - write_unlock_irqrestore(&data->lock, flags);
> + spin_unlock_irqrestore(&data->lock, flags);
>
> return disabled;
> }
> @@ -493,7 +493,7 @@ static int __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)) {
> data->pgtable = pgtable;
> data->domain = domain;
> @@ -511,7 +511,7 @@ static int __sysmmu_enable(struct sysmmu_drvdata *data,
> if (WARN_ON(ret < 0))
> set_sysmmu_inactive(data); /* decrement count */
>
> - write_unlock_irqrestore(&data->lock, flags);
> + spin_unlock_irqrestore(&data->lock, flags);
>
> return ret;
> }
> @@ -602,7 +602,7 @@ static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
>
> data = dev_get_drvdata(client->sysmmu[i]);
>
> - read_lock_irqsave(&data->lock, flags);
> + spin_lock_irqsave(&data->lock, flags);
> if (is_sysmmu_active(data) && data->runtime_active) {
> int i;
> clk_enable(data->clk_master);
> @@ -615,7 +615,7 @@ static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
> "disabled. Skipping TLB invalidation @ %#lx\n",
> iova);
> }
> - read_unlock_irqrestore(&data->lock, flags);
> + spin_unlock_irqrestore(&data->lock, flags);
> }
> }
>
> @@ -630,7 +630,7 @@ void exynos_sysmmu_tlb_invalidate(struct device *dev)
>
> data = dev_get_drvdata(client->sysmmu[i]);
>
> - read_lock_irqsave(&data->lock, flags);
> + spin_lock_irqsave(&data->lock, flags);
> if (is_sysmmu_active(data) &&
> data->runtime_active) {
> int i;
> @@ -646,7 +646,7 @@ void exynos_sysmmu_tlb_invalidate(struct device *dev)
> } else {
> dev_dbg(dev, "disabled. Skipping TLB invalidation\n");
> }
> - read_unlock_irqrestore(&data->lock, flags);
> + spin_unlock_irqrestore(&data->lock, flags);
> }
> }
>
> @@ -735,7 +735,7 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
>
> data->runtime_active = !pm_runtime_enabled(dev);
>
> - rwlock_init(&data->lock);
> + spin_lock_init(&data->lock);
> INIT_LIST_HEAD(&data->node);
>
> platform_set_drvdata(pdev, data);
> @@ -749,11 +749,11 @@ static int sysmmu_suspend(struct device *dev)
> {
> struct sysmmu_drvdata *data = dev_get_drvdata(dev);
> unsigned long flags;
> - read_lock_irqsave(&data->lock, flags);
> + spin_lock_irqsave(&data->lock, flags);
> if (is_sysmmu_active(data) &&
> (!pm_runtime_enabled(dev) || data->runtime_active))
> __sysmmu_disable_nocount(data);
> - read_unlock_irqrestore(&data->lock, flags);
> + spin_unlock_irqrestore(&data->lock, flags);
> return 0;
> }
>
> @@ -761,11 +761,11 @@ static int sysmmu_resume(struct device *dev)
> {
> struct sysmmu_drvdata *data = dev_get_drvdata(dev);
> unsigned long flags;
> - read_lock_irqsave(&data->lock, flags);
> + spin_lock_irqsave(&data->lock, flags);
> if (is_sysmmu_active(data) &&
> (!pm_runtime_enabled(dev) || data->runtime_active))
> __sysmmu_enable_nocount(data);
> - read_unlock_irqrestore(&data->lock, flags);
> + spin_unlock_irqrestore(&data->lock, flags);
> return 0;
> }
> #endif
> --
> 1.7.2.5
>
>