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>
diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 68a15a0..541d210 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -553,11 +553,11 @@
#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 @@
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 @@
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 @@
/* 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 @@
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 @@
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;
}