[PATCH 17/24] x86/amd_gart: remove the mapping_error dma_map_ops method

Christoph Hellwig
2018-11-22T14:03:13Z

Return DMA_MAPPING_ERROR instead of the magic bad_dma_addr on a dma
mapping failure and let the core dma-mapping code handle the rest.

Remove the magic EMERGENCY_PAGES that the bad_dma_addr gets redirected to.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/x86/kernel/amd_gart_64.c | 39 ++++++-----------------------------
1 file changed, 6 insertions(+), 33 deletions(-)

diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index 3f9d1b4019bb..4e733de93f41 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -50,8 +50,6 @@ static unsigned long iommu_pages; /* .. and in pages */

static u32 *iommu_gatt_base; /* Remapping table */

-static dma_addr_t bad_dma_addr;
-
/*
* If this is disabled the IOMMU will use an optimized flushing strategy
* of only flushing when an mapping is reused. With it true the GART is
@@ -74,8 +72,6 @@ static u32 gart_unmapped_entry;
(((x) & 0xfffff000) | (((x) >> 32) << 4) | GPTE_VALID | GPTE_COHERENT)
#define GPTE_DECODE(x) (((x) & 0xfffff000) | (((u64)(x) & 0xff0) << 28))

-#define EMERGENCY_PAGES 32 /* = 128KB */
-
#ifdef CONFIG_AGP
#define AGPEXTERN extern
#else
@@ -184,14 +180,6 @@ static void iommu_full(struct device *dev, size_t size, int dir)
*/

dev_err(dev, "PCI-DMA: Out of IOMMU space for %lu bytes\n", size);
-
- if (size > PAGE_SIZE*EMERGENCY_PAGES) {
- if (dir = PCI_DMA_FROMDEVICE || dir = PCI_DMA_BIDIRECTIONAL)
- panic("PCI-DMA: Memory would be corrupted\n");
- if (dir = PCI_DMA_TODEVICE || dir = PCI_DMA_BIDIRECTIONAL)
- panic(KERN_ERR
- "PCI-DMA: Random memory would be DMAed\n");
- }
#ifdef CONFIG_IOMMU_LEAK
dump_leak();
#endif
@@ -220,7 +208,7 @@ static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
int i;

if (unlikely(phys_mem + size > GART_MAX_PHYS_ADDR))
- return bad_dma_addr;
+ return DMA_MAPPING_ERROR;

iommu_page = alloc_iommu(dev, npages, align_mask);
if (iommu_page = -1) {
@@ -229,7 +217,7 @@ static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
if (panic_on_overflow)
panic("dma_map_area overflow %lu bytes\n", size);
iommu_full(dev, size, dir);
- return bad_dma_addr;
+ return DMA_MAPPING_ERROR;
}

for (i = 0; i < npages; i++) {
@@ -271,7 +259,7 @@ static void gart_unmap_page(struct device *dev, dma_addr_t dma_addr,
int npages;
int i;

- if (dma_addr < iommu_bus_base + EMERGENCY_PAGES*PAGE_SIZE ||
+ if (dma_addr = DMA_MAPPING_ERROR ||
dma_addr >= iommu_bus_base + iommu_size)
return;

@@ -315,7 +303,7 @@ static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,

if (nonforced_iommu(dev, addr, s->length)) {
addr = dma_map_area(dev, addr, s->length, dir, 0);
- if (addr = bad_dma_addr) {
+ if (addr = DMA_MAPPING_ERROR) {
if (i > 0)
gart_unmap_sg(dev, sg, i, dir, 0);
nents = 0;
@@ -471,7 +459,7 @@ static int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents,

iommu_full(dev, pages << PAGE_SHIFT, dir);
for_each_sg(sg, s, nents, i)
- s->dma_address = bad_dma_addr;
+ s->dma_address = DMA_MAPPING_ERROR;
return 0;
}

@@ -490,7 +478,7 @@ gart_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr,
*dma_addr = dma_map_area(dev, virt_to_phys(vaddr), size,
DMA_BIDIRECTIONAL, (1UL << get_order(size)) - 1);
flush_gart();
- if (unlikely(*dma_addr = bad_dma_addr))
+ if (unlikely(*dma_addr = DMA_MAPPING_ERROR))
goto out_free;
return vaddr;
out_free:
@@ -507,11 +495,6 @@ gart_free_coherent(struct device *dev, size_t size, void *vaddr,
dma_direct_free_pages(dev, size, vaddr, dma_addr, attrs);
}

-static int gart_mapping_error(struct device *dev, dma_addr_t dma_addr)
-{
- return (dma_addr = bad_dma_addr);
-}
-
static int no_agp;

static __init unsigned long check_iommu_size(unsigned long aper, u64 aper_size)
@@ -695,7 +678,6 @@ static const struct dma_map_ops gart_dma_ops = {
.unmap_page = gart_unmap_page,
.alloc = gart_alloc_coherent,
.free = gart_free_coherent,
- .mapping_error = gart_mapping_error,
.dma_supported = dma_direct_supported,
};

@@ -784,19 +766,12 @@ int __init gart_iommu_init(void)
}
#endif

- /*
- * Out of IOMMU space handling.
- * Reserve some invalid pages at the beginning of the GART.
- */
- bitmap_set(iommu_gart_bitmap, 0, EMERGENCY_PAGES);
-
pr_info("PCI-DMA: Reserving %luMB of IOMMU area in the AGP aperture\n",
iommu_size >> 20);

agp_memory_reserved = iommu_size;
iommu_start = aper_size - iommu_size;
iommu_bus_base = info.aper_base + iommu_start;
- bad_dma_addr = iommu_bus_base;
iommu_gatt_base = agp_gatt_table + (iommu_start>>PAGE_SHIFT);

/*
@@ -838,8 +813,6 @@ int __init gart_iommu_init(void)
if (!scratch)
panic("Cannot allocate iommu scratch page");
gart_unmapped_entry = GPTE_ENCODE(__pa(scratch));
- for (i = EMERGENCY_PAGES; i < iommu_pages; i++)
- iommu_gatt_base[i] = gart_unmapped_entry;

flush_gart();
dma_ops = &gart_dma_ops;
--
2.19.1