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iommu/amd: Use trylock to aquire bitmap_lock 

First search for a non-contended aperture with trylock
before spinning.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Joerg Roedel 2015-12-22 13:38:12 +01:00
parent 5f6bed5005
commit 7b5e25b84e
1 changed files with 17 additions and 3 deletions
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20
drivers/iommu/amd_iommu.c
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@ -1542,7 +1542,8 @@ static dma_addr_t dma_ops_aperture_alloc(struct dma_ops_domain *dom,
unsigned long pages,
unsigned long dma_mask,
unsigned long boundary_size,
unsigned long align_mask)
unsigned long align_mask,
bool trylock)
{
unsigned long offset, limit, flags;
dma_addr_t address;
@ -1552,7 +1553,13 @@ static dma_addr_t dma_ops_aperture_alloc(struct dma_ops_domain *dom,
limit = iommu_device_max_index(APERTURE_RANGE_PAGES, offset,
dma_mask >> PAGE_SHIFT);
spin_lock_irqsave(&range->bitmap_lock, flags);
if (trylock) {
if (!spin_trylock_irqsave(&range->bitmap_lock, flags))
return -1;
} else {
spin_lock_irqsave(&range->bitmap_lock, flags);
}
address = iommu_area_alloc(range->bitmap, limit, range->next_bit,
pages, offset, boundary_size, align_mask);
if (address == -1) {
@ -1584,12 +1591,14 @@ static unsigned long dma_ops_area_alloc(struct device *dev,
{
unsigned long boundary_size, mask;
unsigned long address = -1;
bool first = true;
u32 start, i;
preempt_disable();
mask = dma_get_seg_boundary(dev);
again:
start = this_cpu_read(*dom->next_index);
/* Sanity check - is it really necessary? */
@ -1614,7 +1623,7 @@ static unsigned long dma_ops_area_alloc(struct device *dev,
address = dma_ops_aperture_alloc(dom, range, pages,
dma_mask, boundary_size,
align_mask);
align_mask, first);
if (address != -1) {
address = range->offset + (address << PAGE_SHIFT);
this_cpu_write(*dom->next_index, index);
@ -1622,6 +1631,11 @@ static unsigned long dma_ops_area_alloc(struct device *dev,
}
}
if (address == -1 && first) {
first = false;
goto again;
}
preempt_enable();
return address;