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Message-id: <009301ce8144$f1172c30$d3458490$@samsung.com>
Date: Mon, 15 Jul 2013 19:20:34 +0900
From: Cho KyongHo <pullip.cho@...sung.com>
To: 'Bartlomiej Zolnierkiewicz' <b.zolnierkie@...sung.com>
Cc: 'Linux ARM Kernel' <linux-arm-kernel@...ts.infradead.org>,
'Linux IOMMU' <iommu@...ts.linux-foundation.org>,
'Linux Kernel' <linux-kernel@...r.kernel.org>,
'Linux Samsung SOC' <linux-samsung-soc@...r.kernel.org>,
'Hyunwoong Kim' <khw0178.kim@...sung.com>,
'Joerg Roedel' <joro@...tes.org>,
'Kukjin Kim' <kgene.kim@...sung.com>,
'Prathyush' <prathyush.k@...sung.com>,
'Rahul Sharma' <rahul.sharma@...sung.com>,
'Subash Patel' <supash.ramaswamy@...aro.org>,
'Keyyoung Park' <keyyoung.park@...sung.com>,
'Grant Grundler' <grundler@...omium.org>
Subject: RE: [PATCH v7 5/9] iommu/exynos: change rwlock to spinlock
> From: Bartlomiej Zolnierkiewicz [mailto:b.zolnierkie@...sung.com]
> Sent: Saturday, July 13, 2013 12:31 AM
>
> Hi,
>
> On Friday, July 05, 2013 09:29:26 PM Cho KyongHo 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.
>
> This change is not of a "fix type" and is not required to make the driver
> work so it would probably be best to move it to the end of a patch series
> (IOW just making it the last patch in the series).
>
Thank you for advice.
I will do that in the next patchset :)
Cho KyongHo.
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
>
> > Signed-off-by: Cho KyongHo <pullip.cho@...sung.com>
> > ---
> > drivers/iommu/exynos-iommu.c | 32 ++++++++++++++++----------------
> > 1 files changed, 16 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> > index 390f8b7..6793661 100644
> > --- a/drivers/iommu/exynos-iommu.c
> > +++ b/drivers/iommu/exynos-iommu.c
> > @@ -175,7 +175,7 @@ struct sysmmu_drvdata {
> > void __iomem **sfrbases;
> > struct clk *clk[2];
> > int activations;
> > - rwlock_t lock;
> > + spinlock_t lock;
> > struct iommu_domain *domain;
> > sysmmu_fault_handler_t fault_handler;
> > unsigned long pgtable;
> > @@ -259,7 +259,7 @@ 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;
> >
> > @@ -289,7 +289,7 @@ void exynos_sysmmu_set_prefbuf(struct device *dev,
> > }
> > }
> > finish:
> > - read_unlock_irqrestore(&data->lock, flags);
> > + spin_unlock_irqrestore(&data->lock, flags);
> > }
> >
> > static void __set_fault_handler(struct sysmmu_drvdata *data,
> > @@ -297,9 +297,9 @@ static void __set_fault_handler(struct sysmmu_drvdata *data,
> > {
> > unsigned long flags;
> >
> > - write_lock_irqsave(&data->lock, flags);
> > + spin_lock_irqsave(&data->lock, flags);
> > data->fault_handler = handler;
> > - write_unlock_irqrestore(&data->lock, flags);
> > + spin_unlock_irqrestore(&data->lock, flags);
> > }
> >
> > void exynos_sysmmu_set_fault_handler(struct device *dev,
> > @@ -347,7 +347,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
> >
> > int i, ret = -ENOSYS;
> >
> > - read_lock(&data->lock);
> > + spin_lock(&data->lock);
> >
> > WARN_ON(!is_sysmmu_active(data));
> >
> > @@ -391,7 +391,7 @@ 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);
> >
> > return IRQ_HANDLED;
> > }
> > @@ -402,7 +402,7 @@ static bool __exynos_sysmmu_disable(struct sysmmu_drvdata *data)
> > bool disabled = false;
> > int i;
> >
> > - write_lock_irqsave(&data->lock, flags);
> > + spin_lock_irqsave(&data->lock, flags);
> >
> > if (!set_sysmmu_inactive(data))
> > goto finish;
> > @@ -419,7 +419,7 @@ 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, "(%s) Disabled\n", data->dbgname);
> > @@ -442,7 +442,7 @@ static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
> > int i, 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)) {
> > @@ -481,7 +481,7 @@ static int __exynos_sysmmu_enable(struct sysmmu_drvdata *data,
> >
> > dev_dbg(data->sysmmu, "(%s) Enabled\n", data->dbgname);
> > finish:
> > - write_unlock_irqrestore(&data->lock, flags);
> > + spin_unlock_irqrestore(&data->lock, flags);
> >
> > return ret;
> > }
> > @@ -528,7 +528,7 @@ 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)) {
> > int i;
> > @@ -545,7 +545,7 @@ static void sysmmu_tlb_invalidate_entry(struct device *dev, unsigned long iova)
> > data->dbgname);
> > }
> >
> > - read_unlock_irqrestore(&data->lock, flags);
> > + spin_unlock_irqrestore(&data->lock, flags);
> > }
> >
> > void exynos_sysmmu_tlb_invalidate(struct device *dev)
> > @@ -553,7 +553,7 @@ 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)) {
> > int i;
> > @@ -569,7 +569,7 @@ void exynos_sysmmu_tlb_invalidate(struct device *dev)
> > data->dbgname);
> > }
> >
> > - read_unlock_irqrestore(&data->lock, flags);
> > + spin_unlock_irqrestore(&data->lock, flags);
> > }
> >
> > static int exynos_sysmmu_probe(struct platform_device *pdev)
> > @@ -666,7 +666,7 @@ 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);
> >
> > __set_fault_handler(data, &default_fault_handler);
--
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