ARM: dmabounce: separate out decision to bounce

Move the decision to perform DMA bouncing out of map_single() into its
own stand-alone function.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
index 3e0fa15..643e1d6 100644 (file)
--- a/arch/arm/common/dmabounce.c
+++ b/arch/arm/common/dmabounce.c
@@ -219,36 +219,46 @@ static struct safe_buffer *find_safe_buffer_dev(struct device *dev,
        return find_safe_buffer(dev->archdata.dmabounce, dma_addr);
 }
 
-static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
-               enum dma_data_direction dir)
+static int needs_bounce(struct device *dev, dma_addr_t dma_addr, size_t size)
 {
-       struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
-       dma_addr_t dma_addr;
-       int needs_bounce = 0;
-
-       if (device_info)
-               DO_STATS ( device_info->map_op_count++ );
-
-       dma_addr = virt_to_dma(dev, ptr);
+       if (!dev || !dev->archdata.dmabounce)
+               return 0;
 
        if (dev->dma_mask) {
-               unsigned long mask = *dev->dma_mask;
-               unsigned long limit;
+               unsigned long limit, mask = *dev->dma_mask;
 
                limit = (mask + 1) & ~mask;
                if (limit && size > limit) {
                        dev_err(dev, "DMA mapping too big (requested %#x "
                                "mask %#Lx)\n", size, *dev->dma_mask);
-                       return ~0;
+                       return -E2BIG;
                }
 
-               /*
-                * Figure out if we need to bounce from the DMA mask.
-                */
-               needs_bounce = (dma_addr | (dma_addr + size - 1)) & ~mask;
+               /* Figure out if we need to bounce from the DMA mask. */
+               if ((dma_addr | (dma_addr + size - 1)) & ~mask)
+                       return 1;
        }
 
-       if (device_info && (needs_bounce || dma_needs_bounce(dev, dma_addr, size))) {
+       return dma_needs_bounce(dev, dma_addr, size) ? 1 : 0;
+}
+
+static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size,
+               enum dma_data_direction dir)
+{
+       struct dmabounce_device_info *device_info = dev->archdata.dmabounce;
+       dma_addr_t dma_addr;
+       int ret;
+
+       if (device_info)
+               DO_STATS ( device_info->map_op_count++ );
+
+       dma_addr = virt_to_dma(dev, ptr);
+
+       ret = needs_bounce(dev, dma_addr, size);
+       if (ret < 0)
+               return ~0;
+
+       if (ret > 0) {
                struct safe_buffer *buf;
 
                buf = alloc_safe_buffer(device_info, ptr, size, dir);