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>

1 files changed, 5 insertions, 13 deletions

diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index eaa213e21592..fcf59fcae1bc 100644
--- 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;