[Xen-devel] [PATCH 19/44] s390: implement ->mapping_error

[Christoph Hellwig <hch@xxxxxx>]

s390 can also use noop_dma_ops, and while that currently does not return
errors it will so in the future.  Implementing the mapping_error method
is the proper way to have per-ops error conditions.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 arch/s390/include/asm/dma-mapping.h |  2 --
 arch/s390/pci/pci_dma.c             | 18 +++++++++++++-----
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/arch/s390/include/asm/dma-mapping.h 
b/arch/s390/include/asm/dma-mapping.h
index 3108b8dbe266..512ad0eaa11a 100644
--- a/arch/s390/include/asm/dma-mapping.h
+++ b/arch/s390/include/asm/dma-mapping.h
@@ -8,8 +8,6 @@
 #include <linux/dma-debug.h>
 #include <linux/io.h>
 
-#define DMA_ERROR_CODE         (~(dma_addr_t) 0x0)
-
 extern const struct dma_map_ops s390_pci_dma_ops;
 
 static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index 9081a57fa340..ea623faab525 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -14,6 +14,8 @@
 #include <linux/pci.h>
 #include <asm/pci_dma.h>
 
+#define S390_MAPPING_ERROR             (~(dma_addr_t) 0x0)
+
 static struct kmem_cache *dma_region_table_cache;
 static struct kmem_cache *dma_page_table_cache;
 static int s390_iommu_strict;
@@ -281,7 +283,7 @@ static dma_addr_t dma_alloc_address(struct device *dev, int 
size)
 
 out_error:
        spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
-       return DMA_ERROR_CODE;
+       return S390_MAPPING_ERROR;
 }
 
 static void dma_free_address(struct device *dev, dma_addr_t dma_addr, int size)
@@ -329,7 +331,7 @@ static dma_addr_t s390_dma_map_pages(struct device *dev, 
struct page *page,
        /* This rounds up number of pages based on size and offset */
        nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
        dma_addr = dma_alloc_address(dev, nr_pages);
-       if (dma_addr == DMA_ERROR_CODE) {
+       if (dma_addr == S390_MAPPING_ERROR) {
                ret = -ENOSPC;
                goto out_err;
        }
@@ -352,7 +354,7 @@ static dma_addr_t s390_dma_map_pages(struct device *dev, 
struct page *page,
 out_err:
        zpci_err("map error:\n");
        zpci_err_dma(ret, pa);
-       return DMA_ERROR_CODE;
+       return S390_MAPPING_ERROR;
 }
 
 static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
@@ -429,7 +431,7 @@ static int __s390_dma_map_sg(struct device *dev, struct 
scatterlist *sg,
        int ret;
 
        dma_addr_base = dma_alloc_address(dev, nr_pages);
-       if (dma_addr_base == DMA_ERROR_CODE)
+       if (dma_addr_base == S390_MAPPING_ERROR)
                return -ENOMEM;
 
        dma_addr = dma_addr_base;
@@ -476,7 +478,7 @@ static int s390_dma_map_sg(struct device *dev, struct 
scatterlist *sg,
        for (i = 1; i < nr_elements; i++) {
                s = sg_next(s);
 
-               s->dma_address = DMA_ERROR_CODE;
+               s->dma_address = S390_MAPPING_ERROR;
                s->dma_length = 0;
 
                if (s->offset || (size & ~PAGE_MASK) ||
@@ -525,6 +527,11 @@ static void s390_dma_unmap_sg(struct device *dev, struct 
scatterlist *sg,
                s->dma_length = 0;
        }
 }
+       
+static int s390_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+       return dma_addr == S390_MAPPING_ERROR;
+}
 
 int zpci_dma_init_device(struct zpci_dev *zdev)
 {
@@ -657,6 +664,7 @@ const struct dma_map_ops s390_pci_dma_ops = {
        .unmap_sg       = s390_dma_unmap_sg,
        .map_page       = s390_dma_map_pages,
        .unmap_page     = s390_dma_unmap_pages,
+       .mapping_error  = s390_mapping_error,
        /* if we support direct DMA this must be conditional */
        .is_phys        = 0,
        /* dma_supported is unconditionally true without a callback */
-- 
2.11.0


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