1 files changed, 21 insertions, 14 deletions

diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 5826ae333b19..7570b71a2453 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -750,20 +750,19 @@ static void ar_context_tasklet(unsigned long data)
                  */
 
                 offset = offsetof(struct ar_buffer, data);
-                start = buffer = ab;
+                start = ab;
                 start_bus = le32_to_cpu(ab->descriptor.data_address) - offset;
+                buffer = ab->data;
 
                 ab = ab->next;
                 d = &ab->descriptor;
-                size = buffer + PAGE_SIZE - ctx->pointer;
+                size = start + PAGE_SIZE - ctx->pointer;
                 /* valid buffer data in the next page */
                 rest = le16_to_cpu(d->req_count) - le16_to_cpu(d->res_count);
                 /* what actually fits in this page */
-                size2 = min(rest, (size_t)PAGE_SIZE - size);
+                size2 = min(rest, (size_t)PAGE_SIZE - offset - size);
                 memmove(buffer, ctx->pointer, size);
                 memcpy(buffer + size, ab->data, size2);
-                ctx->current_buffer = ab;
-                ctx->pointer = (void *) ab->data + rest;
 
                 while (size > 0) {
                         void *next = handle_ar_packet(ctx, buffer);
@@ -782,22 +781,30 @@ static void ar_context_tasklet(unsigned long data)
                         size -= pktsize;
                         /* fill up this page again */
                         size3 = min(rest - size2,
-                                    (size_t)PAGE_SIZE - size - size2);
+                                    (size_t)PAGE_SIZE - offset - size - size2);
                         memcpy(buffer + size + size2,
                                (void *) ab->data + size2, size3);
                         size2 += size3;
                 }
 
-                /* handle the packets that are fully in the next page */
-                buffer = (void *) ab->data + (buffer - (start + size));
-                end = (void *) ab->data + rest;
+                if (rest > 0) {
+                        /* handle the packets that are fully in the next page */
+                        buffer = (void *) ab->data +
+                                        (buffer - (start + offset + size));
+                        end = (void *) ab->data + rest;
 
-                while (buffer < end)
-                        buffer = handle_ar_packet(ctx, buffer);
+                        while (buffer < end)
+                                buffer = handle_ar_packet(ctx, buffer);
+
+                        ctx->current_buffer = ab;
+                        ctx->pointer = end;
 
-                dma_free_coherent(ohci->card.device, PAGE_SIZE,
-                                  start, start_bus);
-                ar_context_add_page(ctx);
+                        dma_free_coherent(ohci->card.device, PAGE_SIZE,
+                                          start, start_bus);
+                        ar_context_add_page(ctx);
+                } else {
+                        ctx->pointer = start + PAGE_SIZE;
+                }
         } else {
                 buffer = ctx->pointer;
                 ctx->pointer = end =