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Subject[PATCH 2/3] x86: kill bad_dma_address variable
Date
This kills bad_dma_address variable, the old mechanism to enable IOMMU
drivers to make dma_mapping_error() work in IOMMU's specific way.

bad_dma_address variable was introduced to enable IOMMU drivers to
make dma_mapping_error() work in IOMMU's specific way. However, it
can't handle systems that use both swiotlb and HW IOMMU. SO we
introduced dma_map_ops->mapping_error to solve that case.

Intel VT-d, GART, and swiotlb already use
dma_map_ops->mapping_error. Calgary, AMD IOMMU, and nommu use zero for
an error dma address. This adds DMA_ERROR_CODE and converts them to
use it (as SPARC and POWER does).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
---
arch/x86/include/asm/dma-mapping.h | 5 +++--
arch/x86/kernel/amd_iommu.c | 21 ++++++++++-----------
arch/x86/kernel/pci-calgary_64.c | 22 ++++++++++------------
arch/x86/kernel/pci-dma.c | 3 ---
arch/x86/kernel/pci-nommu.c | 2 +-
5 files changed, 24 insertions(+), 29 deletions(-)

diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index 6a25d5d..0f6c02f 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -20,7 +20,8 @@
# define ISA_DMA_BIT_MASK DMA_BIT_MASK(32)
#endif

-extern dma_addr_t bad_dma_address;
+#define DMA_ERROR_CODE 0
+
extern int iommu_merge;
extern struct device x86_dma_fallback_dev;
extern int panic_on_overflow;
@@ -48,7 +49,7 @@ static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
if (ops->mapping_error)
return ops->mapping_error(dev, dma_addr);

- return (dma_addr == bad_dma_address);
+ return (dma_addr == DMA_ERROR_CODE);
}

#define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent(d, s, h, f)
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 66237fd..093bd52 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -928,7 +928,7 @@ static unsigned long dma_ops_alloc_addresses(struct device *dev,
}

if (unlikely(address == -1))
- address = bad_dma_address;
+ address = DMA_ERROR_CODE;

WARN_ON((address + (PAGE_SIZE*pages)) > dom->aperture_size);

@@ -1544,7 +1544,7 @@ static dma_addr_t dma_ops_domain_map(struct amd_iommu *iommu,

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

__pte = paddr | IOMMU_PTE_P | IOMMU_PTE_FC;

@@ -1625,7 +1625,7 @@ static dma_addr_t __map_single(struct device *dev,
retry:
address = dma_ops_alloc_addresses(dev, dma_dom, pages, align_mask,
dma_mask);
- if (unlikely(address == bad_dma_address)) {
+ if (unlikely(address == DMA_ERROR_CODE)) {
/*
* setting next_address here will let the address
* allocator only scan the new allocated range in the
@@ -1646,7 +1646,7 @@ retry:
start = address;
for (i = 0; i < pages; ++i) {
ret = dma_ops_domain_map(iommu, dma_dom, start, paddr, dir);
- if (ret == bad_dma_address)
+ if (ret == DMA_ERROR_CODE)
goto out_unmap;

paddr += PAGE_SIZE;
@@ -1674,7 +1674,7 @@ out_unmap:

dma_ops_free_addresses(dma_dom, address, pages);

- return bad_dma_address;
+ return DMA_ERROR_CODE;
}

/*
@@ -1690,7 +1690,7 @@ static void __unmap_single(struct amd_iommu *iommu,
dma_addr_t i, start;
unsigned int pages;

- if ((dma_addr == bad_dma_address) ||
+ if ((dma_addr == DMA_ERROR_CODE) ||
(dma_addr + size > dma_dom->aperture_size))
return;

@@ -1732,7 +1732,7 @@ static dma_addr_t map_page(struct device *dev, struct page *page,
INC_STATS_COUNTER(cnt_map_single);

if (!check_device(dev))
- return bad_dma_address;
+ return DMA_ERROR_CODE;

dma_mask = *dev->dma_mask;

@@ -1743,12 +1743,12 @@ static dma_addr_t map_page(struct device *dev, struct page *page,
return (dma_addr_t)paddr;

if (!dma_ops_domain(domain))
- return bad_dma_address;
+ return DMA_ERROR_CODE;

spin_lock_irqsave(&domain->lock, flags);
addr = __map_single(dev, iommu, domain->priv, paddr, size, dir, false,
dma_mask);
- if (addr == bad_dma_address)
+ if (addr == DMA_ERROR_CODE)
goto out;

iommu_completion_wait(iommu);
@@ -1957,7 +1957,7 @@ static void *alloc_coherent(struct device *dev, size_t size,
*dma_addr = __map_single(dev, iommu, domain->priv, paddr,
size, DMA_BIDIRECTIONAL, true, dma_mask);

- if (*dma_addr == bad_dma_address) {
+ if (*dma_addr == DMA_ERROR_CODE) {
spin_unlock_irqrestore(&domain->lock, flags);
goto out_free;
}
@@ -2110,7 +2110,6 @@ int __init amd_iommu_init_dma_ops(void)
prealloc_protection_domains();

iommu_detected = 1;
- bad_dma_address = 0;
swiotlb = 0;
#ifdef CONFIG_GART_IOMMU
gart_iommu_aperture_disabled = 1;
diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c
index c84ad03..af9f436 100644
--- a/arch/x86/kernel/pci-calgary_64.c
+++ b/arch/x86/kernel/pci-calgary_64.c
@@ -245,7 +245,7 @@ static unsigned long iommu_range_alloc(struct device *dev,
if (panic_on_overflow)
panic("Calgary: fix the allocator.\n");
else
- return bad_dma_address;
+ return DMA_ERROR_CODE;
}
}

@@ -261,11 +261,11 @@ static dma_addr_t iommu_alloc(struct device *dev, struct iommu_table *tbl,
void *vaddr, unsigned int npages, int direction)
{
unsigned long entry;
- dma_addr_t ret = bad_dma_address;
+ dma_addr_t ret = DMA_ERROR_CODE;

entry = iommu_range_alloc(dev, tbl, npages);

- if (unlikely(entry == bad_dma_address))
+ if (unlikely(entry == DMA_ERROR_CODE))
goto error;

/* set the return dma address */
@@ -280,7 +280,7 @@ static dma_addr_t iommu_alloc(struct device *dev, struct iommu_table *tbl,
error:
printk(KERN_WARNING "Calgary: failed to allocate %u pages in "
"iommu %p\n", npages, tbl);
- return bad_dma_address;
+ return DMA_ERROR_CODE;
}

static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
@@ -291,8 +291,8 @@ static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
unsigned long flags;

/* were we called with bad_dma_address? */
- badend = bad_dma_address + (EMERGENCY_PAGES * PAGE_SIZE);
- if (unlikely((dma_addr >= bad_dma_address) && (dma_addr < badend))) {
+ badend = DMA_ERROR_CODE + (EMERGENCY_PAGES * PAGE_SIZE);
+ if (unlikely((dma_addr >= DMA_ERROR_CODE) && (dma_addr < badend))) {
WARN(1, KERN_ERR "Calgary: driver tried unmapping bad DMA "
"address 0x%Lx\n", dma_addr);
return;
@@ -374,7 +374,7 @@ static int calgary_map_sg(struct device *dev, struct scatterlist *sg,
npages = iommu_num_pages(vaddr, s->length, PAGE_SIZE);

entry = iommu_range_alloc(dev, tbl, npages);
- if (entry == bad_dma_address) {
+ if (entry == DMA_ERROR_CODE) {
/* makes sure unmap knows to stop */
s->dma_length = 0;
goto error;
@@ -392,7 +392,7 @@ static int calgary_map_sg(struct device *dev, struct scatterlist *sg,
error:
calgary_unmap_sg(dev, sg, nelems, dir, NULL);
for_each_sg(sg, s, nelems, i) {
- sg->dma_address = bad_dma_address;
+ sg->dma_address = DMA_ERROR_CODE;
sg->dma_length = 0;
}
return 0;
@@ -447,7 +447,7 @@ static void* calgary_alloc_coherent(struct device *dev, size_t size,

/* set up tces to cover the allocated range */
mapping = iommu_alloc(dev, tbl, ret, npages, DMA_BIDIRECTIONAL);
- if (mapping == bad_dma_address)
+ if (mapping == DMA_ERROR_CODE)
goto free;
*dma_handle = mapping;
return ret;
@@ -728,7 +728,7 @@ static void __init calgary_reserve_regions(struct pci_dev *dev)
struct iommu_table *tbl = pci_iommu(dev->bus);

/* reserve EMERGENCY_PAGES from bad_dma_address and up */
- iommu_range_reserve(tbl, bad_dma_address, EMERGENCY_PAGES);
+ iommu_range_reserve(tbl, DMA_ERROR_CODE, EMERGENCY_PAGES);

/* avoid the BIOS/VGA first 640KB-1MB region */
/* for CalIOC2 - avoid the entire first MB */
@@ -1359,8 +1359,6 @@ static int __init calgary_iommu_init(void)
return ret;
}

- bad_dma_address = 0x0;
-
return 0;
}

diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index bf621b9..afcc58b 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -43,9 +43,6 @@ int iommu_detected __read_mostly = 0;
*/
int iommu_pass_through __read_mostly;

-dma_addr_t bad_dma_address __read_mostly = 0;
-EXPORT_SYMBOL(bad_dma_address);
-
/* Dummy device used for NULL arguments (normally ISA). */
struct device x86_dma_fallback_dev = {
.init_name = "fallback device",
diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c
index 875e382..22be12b 100644
--- a/arch/x86/kernel/pci-nommu.c
+++ b/arch/x86/kernel/pci-nommu.c
@@ -33,7 +33,7 @@ static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
dma_addr_t bus = page_to_phys(page) + offset;
WARN_ON(size == 0);
if (!check_addr("map_single", dev, bus, size))
- return bad_dma_address;
+ return DMA_ERROR_CODE;
flush_write_buffers();
return bus;
}
--
1.5.6.5


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