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iommu/tegra: Don't call alloc_pdir with as->lock 

Instead of taking as->lock before calling alloc_pdir() and
releasing it in that function to allocate memory, just take
the lock only in the alloc_pdir function and run the loop
without any lock held. This simplifies the complicated
lock->unlock->alloc->lock->unlock sequence into
alloc->lock->unlock.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This commit is contained in:
Joerg Roedel 2012-07-17 11:47:14 +02:00
parent 9e971a03af
commit f9a4f063a8
1 changed files with 16 additions and 13 deletions
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29
drivers/iommu/tegra-smmu.c
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@ -553,11 +553,11 @@ static inline void put_signature(struct smmu_as *as,
#endif
/*
* Caller must lock/unlock as
* Caller must not hold as->lock
*/
static int alloc_pdir(struct smmu_as *as, unsigned long *flags)
static int alloc_pdir(struct smmu_as *as)
{
unsigned long *pdir;
unsigned long *pdir, flags;
int pdn, err = 0;
u32 val;
struct smmu_device *smmu = as->smmu;
@ -565,13 +565,14 @@ static int alloc_pdir(struct smmu_as *as, unsigned long *flags)
unsigned int *cnt;
/*
* do the allocation outside the as->lock
* do the allocation, then grab as->lock
*/
spin_unlock_irqrestore(&as->lock, *flags);
cnt = devm_kzalloc(smmu->dev,
sizeof(cnt[0]) * SMMU_PDIR_COUNT, GFP_KERNEL);
sizeof(cnt[0]) * SMMU_PDIR_COUNT,
GFP_KERNEL);
page = alloc_page(GFP_KERNEL | __GFP_DMA);
spin_lock_irqsave(&as->lock, *flags);
spin_lock_irqsave(&as->lock, flags);
if (as->pdir_page) {
/* We raced, free the redundant */
@ -603,9 +604,13 @@ static int alloc_pdir(struct smmu_as *as, unsigned long *flags)
smmu_write(smmu, val, SMMU_TLB_FLUSH);
FLUSH_SMMU_REGS(as->smmu);
spin_unlock_irqrestore(&as->lock, flags);
return 0;
err_out:
spin_unlock_irqrestore(&as->lock, flags);
devm_kfree(smmu->dev, cnt);
if (page)
__free_page(page);
@ -809,13 +814,11 @@ static int smmu_iommu_domain_init(struct iommu_domain *domain)
/* Look for a free AS with lock held */
for (i = 0; i < smmu->num_as; i++) {
as = &smmu->as[i];
spin_lock_irqsave(&as->lock, flags);
if (!as->pdir_page) {
err = alloc_pdir(as, &flags);
err = alloc_pdir(as);
if (!err)
goto found;
}
spin_unlock_irqrestore(&as->lock, flags);
if (err != -EAGAIN)
break;
}
@ -824,7 +827,7 @@ static int smmu_iommu_domain_init(struct iommu_domain *domain)
return err;
found:
spin_lock(&smmu->lock);
spin_lock_irqsave(&smmu->lock, flags);
/* Update PDIR register */
smmu_write(smmu, SMMU_PTB_ASID_CUR(as->asid), SMMU_PTB_ASID);
@ -832,12 +835,12 @@ found:
SMMU_MK_PDIR(as->pdir_page, as->pdir_attr), SMMU_PTB_DATA);
FLUSH_SMMU_REGS(smmu);
spin_unlock(&smmu->lock);
spin_unlock_irqrestore(&smmu->lock, flags);
spin_unlock_irqrestore(&as->lock, flags);
domain->priv = as;
dev_dbg(smmu->dev, "smmu_as@%p\n", as);
return 0;
}