firewire: fw-ohci: use dma_alloc_coherent for ar_buffer

Currently, we do nothing to guarantee we have a consistent DMA buffer for
asynchronous receive packets. Rather than doing several sync's following a
dma_map_single() to get consistent buffers, just switch to using
dma_alloc_coherent().

Resolves constant buffer failures on my own x86_64 laptop w/4GB of RAM and
likely to fix a number of other failures witnessed on x86_64 systems with
4GB of RAM or more.

Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index eaa213e215926f281e14f55480cdab83e424b8d0..fcf59fcae1bc34e3820f7c34c8cd0e9118f2b2a2 100644 (file)
--- a/drivers/firewire/fw-ohci.c
+++ b/drivers/firewire/fw-ohci.c
@@ -284,16 +284,10 @@ static int ar_context_add_page(struct ar_context *ctx)
        dma_addr_t ab_bus;
        size_t offset;
 
-       ab = (struct ar_buffer *) __get_free_page(GFP_ATOMIC);
+       ab = dma_alloc_coherent(dev, PAGE_SIZE, &ab_bus, GFP_ATOMIC);
        if (ab == NULL)
                return -ENOMEM;
 
-       ab_bus = dma_map_single(dev, ab, PAGE_SIZE, DMA_BIDIRECTIONAL);
-       if (dma_mapping_error(ab_bus)) {
-               free_page((unsigned long) ab);
-               return -ENOMEM;
-       }
-
        memset(&ab->descriptor, 0, sizeof(ab->descriptor));
        ab->descriptor.control        = cpu_to_le16(DESCRIPTOR_INPUT_MORE |
                                                    DESCRIPTOR_STATUS |
@@ -304,8 +298,6 @@ static int ar_context_add_page(struct ar_context *ctx)
        ab->descriptor.res_count      = cpu_to_le16(PAGE_SIZE - offset);
        ab->descriptor.branch_address = 0;
 
-       dma_sync_single_for_device(dev, ab_bus, PAGE_SIZE, DMA_BIDIRECTIONAL);
-
        ctx->last_buffer->descriptor.branch_address = cpu_to_le32(ab_bus | 1);
        ctx->last_buffer->next = ab;
        ctx->last_buffer = ab;
@@ -409,6 +401,7 @@ static void ar_context_tasklet(unsigned long data)
 
        if (d->res_count == 0) {
                size_t size, rest, offset;
+               dma_addr_t buffer_bus;
 
                /*
                 * This descriptor is finished and we may have a
@@ -417,9 +410,7 @@ static void ar_context_tasklet(unsigned long data)
                 */
 
                offset = offsetof(struct ar_buffer, data);
-               dma_unmap_single(ohci->card.device,
-                       le32_to_cpu(ab->descriptor.data_address) - offset,
-                       PAGE_SIZE, DMA_BIDIRECTIONAL);
+               buffer_bus = le32_to_cpu(ab->descriptor.data_address) - offset;
 
                buffer = ab;
                ab = ab->next;
@@ -435,7 +426,8 @@ static void ar_context_tasklet(unsigned long data)
                while (buffer < end)
                        buffer = handle_ar_packet(ctx, buffer);
 
-               free_page((unsigned long)buffer);
+               dma_free_coherent(ohci->card.device, PAGE_SIZE,
+                                 buffer, buffer_bus);
                ar_context_add_page(ctx);
        } else {
                buffer = ctx->pointer;