[PATCH 03/12] amd-iommu: handle page table allocation failures in dma_ops code

From: Joerg Roedel
Date: Fri May 22 2009 - 08:23:56 EST


[ impact: preperation for extended address allocator ]

The code will be required when the aperture size increases dynamically.

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
arch/x86/kernel/amd_iommu.c | 20 ++++++++++++++++++--
1 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index ded79f7..a467add 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -1193,6 +1193,8 @@ static dma_addr_t dma_ops_domain_map(struct amd_iommu *iommu,
paddr &= PAGE_MASK;

pte = dma_ops_get_pte(dom, address);
+ if (!pte)
+ return bad_dma_address;

__pte = paddr | IOMMU_PTE_P | IOMMU_PTE_FC;

@@ -1248,7 +1250,7 @@ static dma_addr_t __map_single(struct device *dev,
u64 dma_mask)
{
dma_addr_t offset = paddr & ~PAGE_MASK;
- dma_addr_t address, start;
+ dma_addr_t address, start, ret;
unsigned int pages;
unsigned long align_mask = 0;
int i;
@@ -1271,7 +1273,10 @@ static dma_addr_t __map_single(struct device *dev,

start = address;
for (i = 0; i < pages; ++i) {
- dma_ops_domain_map(iommu, dma_dom, start, paddr, dir);
+ ret = dma_ops_domain_map(iommu, dma_dom, start, paddr, dir);
+ if (ret == bad_dma_address)
+ goto out_unmap;
+
paddr += PAGE_SIZE;
start += PAGE_SIZE;
}
@@ -1287,6 +1292,17 @@ static dma_addr_t __map_single(struct device *dev,

out:
return address;
+
+out_unmap:
+
+ for (--i; i >= 0; --i) {
+ start -= PAGE_SIZE;
+ dma_ops_domain_unmap(iommu, dma_dom, start);
+ }
+
+ dma_ops_free_addresses(dma_dom, address, pages);
+
+ return bad_dma_address;
}

/*
--
1.6.3.1


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