dma-mapping: don't store redundant offsets

A bus_dma_region necessarily stores both CPU and DMA base addresses for
a range, so there's no need to also store the difference between them.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 02bb2cce423f47d6bc1a1c4e6563a6de6369514d..ee88a727f20039b02db627cef9d3f854061fc161 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1532,7 +1532,6 @@ int acpi_dma_get_range(struct device *dev, const struct bus_dma_region **map)
                        r->cpu_start = rentry->res->start;
                        r->dma_start = rentry->res->start - rentry->offset;
                        r->size = resource_size(rentry->res);
-                       r->offset = rentry->offset;
                        r++;
                }
        }

diff --git a/drivers/of/address.c b/drivers/of/address.c
index b59956310f66454655197d779dc5689bfad22502..ae46a36059045ae39d768472960937f3d0d0651b 100644 (file)
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -955,7 +955,6 @@ int of_dma_get_range(struct device_node *np, const struct bus_dma_region **map)
                r->cpu_start = range.cpu_addr;
                r->dma_start = range.bus_addr;
                r->size = range.size;
-               r->offset = range.cpu_addr - range.bus_addr;
                r++;
        }
 out:

diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index 18aade195884d7b3e3899dc89175e300f58434e0..3eb3589ff43e9320d65f84a7ac0e22a73efd4118 100644 (file)
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -21,7 +21,6 @@ struct bus_dma_region {
        phys_addr_t     cpu_start;
        dma_addr_t      dma_start;
        u64             size;
-       u64             offset;
 };
 
 static inline dma_addr_t translate_phys_to_dma(struct device *dev,
@@ -29,9 +28,12 @@ static inline dma_addr_t translate_phys_to_dma(struct device *dev,
 {
        const struct bus_dma_region *m;
 
-       for (m = dev->dma_range_map; m->size; m++)
-               if (paddr >= m->cpu_start && paddr - m->cpu_start < m->size)
-                       return (dma_addr_t)paddr - m->offset;
+       for (m = dev->dma_range_map; m->size; m++) {
+               u64 offset = paddr - m->cpu_start;
+
+               if (paddr >= m->cpu_start && offset < m->size)
+                       return m->dma_start + offset;
+       }
 
        /* make sure dma_capable fails when no translation is available */
        return DMA_MAPPING_ERROR;
@@ -42,9 +44,12 @@ static inline phys_addr_t translate_dma_to_phys(struct device *dev,
 {
        const struct bus_dma_region *m;
 
-       for (m = dev->dma_range_map; m->size; m++)
-               if (dma_addr >= m->dma_start && dma_addr - m->dma_start < m->size)
-                       return (phys_addr_t)dma_addr + m->offset;
+       for (m = dev->dma_range_map; m->size; m++) {
+               u64 offset = dma_addr - m->dma_start;
+
+               if (dma_addr >= m->dma_start && offset < m->size)
+                       return m->cpu_start + offset;
+       }
 
        return (phys_addr_t)-1;
 }

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 73c95815789a0fd67f8b6d73d44586c48e0111fd..98b2e192fd6965be62e105333ba04a5cc5319f6b 100644 (file)
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -677,7 +677,6 @@ int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start,
                return -ENOMEM;
        map[0].cpu_start = cpu_start;
        map[0].dma_start = dma_start;
-       map[0].offset = offset;
        map[0].size = size;
        dev->dma_range_map = map;
        return 0;