[Xen-devel] [PATCH 18/24] x86/calgary: remove the mapping_error dma_map_ops method

[Christoph Hellwig <hch@xxxxxx>]

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@xxxxxx>
---
 arch/x86/kernel/pci-calgary_64.c | 29 +++++++----------------------
 1 file changed, 7 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c
index bbfc8b1e9104..e76ec1b8ed1f 100644
--- a/arch/x86/kernel/pci-calgary_64.c
+++ b/arch/x86/kernel/pci-calgary_64.c
@@ -51,8 +51,6 @@
 #include <asm/x86_init.h>
 #include <asm/iommu_table.h>
 
-#define CALGARY_MAPPING_ERROR  0
-
 #ifdef CONFIG_CALGARY_IOMMU_ENABLED_BY_DEFAULT
 int use_calgary __read_mostly = 1;
 #else
@@ -157,8 +155,6 @@ static const unsigned long phb_debug_offsets[] = {
 
 #define PHB_DEBUG_STUFF_OFFSET 0x0020
 
-#define EMERGENCY_PAGES 32 /* = 128KB */
-
 unsigned int specified_table_size = TCE_TABLE_SIZE_UNSPECIFIED;
 static int translate_empty_slots __read_mostly = 0;
 static int calgary_detected __read_mostly = 0;
@@ -255,7 +251,7 @@ static unsigned long iommu_range_alloc(struct device *dev,
                        if (panic_on_overflow)
                                panic("Calgary: fix the allocator.\n");
                        else
-                               return CALGARY_MAPPING_ERROR;
+                               return DMA_MAPPING_ERROR;
                }
        }
 
@@ -274,11 +270,10 @@ static dma_addr_t iommu_alloc(struct device *dev, struct 
iommu_table *tbl,
        dma_addr_t ret;
 
        entry = iommu_range_alloc(dev, tbl, npages);
-
-       if (unlikely(entry == CALGARY_MAPPING_ERROR)) {
+       if (unlikely(entry == DMA_MAPPING_ERROR)) {
                pr_warn("failed to allocate %u pages in iommu %p\n",
                        npages, tbl);
-               return CALGARY_MAPPING_ERROR;
+               return DMA_MAPPING_ERROR;
        }
 
        /* set the return dma address */
@@ -298,8 +293,7 @@ static void iommu_free(struct iommu_table *tbl, dma_addr_t 
dma_addr,
        unsigned long flags;
 
        /* were we called with bad_dma_address? */
-       badend = CALGARY_MAPPING_ERROR + (EMERGENCY_PAGES * PAGE_SIZE);
-       if (unlikely(dma_addr < badend)) {
+       if (unlikely(dma_addr == DMA_MAPPING_ERROR)) {
                WARN(1, KERN_ERR "Calgary: driver tried unmapping bad DMA "
                       "address 0x%Lx\n", dma_addr);
                return;
@@ -383,7 +377,7 @@ 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 == CALGARY_MAPPING_ERROR) {
+               if (entry == DMA_MAPPING_ERROR) {
                        /* makes sure unmap knows to stop */
                        s->dma_length = 0;
                        goto error;
@@ -401,7 +395,7 @@ static int calgary_map_sg(struct device *dev, struct 
scatterlist *sg,
 error:
        calgary_unmap_sg(dev, sg, nelems, dir, 0);
        for_each_sg(sg, s, nelems, i) {
-               sg->dma_address = CALGARY_MAPPING_ERROR;
+               sg->dma_address = DMA_MAPPING_ERROR;
                sg->dma_length = 0;
        }
        return 0;
@@ -454,7 +448,7 @@ 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 == CALGARY_MAPPING_ERROR)
+       if (mapping == DMA_MAPPING_ERROR)
                goto free;
        *dma_handle = mapping;
        return ret;
@@ -479,11 +473,6 @@ static void calgary_free_coherent(struct device *dev, 
size_t size,
        free_pages((unsigned long)vaddr, get_order(size));
 }
 
-static int calgary_mapping_error(struct device *dev, dma_addr_t dma_addr)
-{
-       return dma_addr == CALGARY_MAPPING_ERROR;
-}
-
 static const struct dma_map_ops calgary_dma_ops = {
        .alloc = calgary_alloc_coherent,
        .free = calgary_free_coherent,
@@ -491,7 +480,6 @@ static const struct dma_map_ops calgary_dma_ops = {
        .unmap_sg = calgary_unmap_sg,
        .map_page = calgary_map_page,
        .unmap_page = calgary_unmap_page,
-       .mapping_error = calgary_mapping_error,
        .dma_supported = dma_direct_supported,
 };
 
@@ -739,9 +727,6 @@ static void __init calgary_reserve_regions(struct pci_dev 
*dev)
        u64 start;
        struct iommu_table *tbl = pci_iommu(dev->bus);
 
-       /* reserve EMERGENCY_PAGES from bad_dma_address and up */
-       iommu_range_reserve(tbl, CALGARY_MAPPING_ERROR, EMERGENCY_PAGES);
-
        /* avoid the BIOS/VGA first 640KB-1MB region */
        /* for CalIOC2 - avoid the entire first MB */
        if (is_calgary(dev->device)) {
-- 
2.19.1


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