firewire: fw-ohci: fix IOMMU resource exhaustion

There is a DMA map/ unmap imbalance whenever a block write request
packet is sent and then dequeued with ohci_cancel_packet.  The latter
may happen frequently if the AR resp tasklet is executed before the AT
req tasklet for the same transaction.

Add the missing dma_unmap_single.  This fixes
https://bugzilla.redhat.com/show_bug.cgi?id=475156

Reported-by: Emmanuel Kowalski
Tested-by: Emmanuel Kowalski
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

1 files changed, 7 insertions, 4 deletions

diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index 46610b090415..ab9c01e462ef 100644
--- a/drivers/firewire/fw-ohci.c
+++ b/drivers/firewire/fw-ohci.c
@@ -974,6 +974,7 @@ at_context_queue_packet(struct context *ctx, struct fw_packet *packet)
                         packet->ack = RCODE_SEND_ERROR;
                         return -1;
                 }
+                packet->payload_bus = payload_bus;
 
                 d[2].req_count    = cpu_to_le16(packet->payload_length);
                 d[2].data_address = cpu_to_le32(payload_bus);
@@ -1025,7 +1026,6 @@ static int handle_at_packet(struct context *context,
         struct driver_data *driver_data;
         struct fw_packet *packet;
         struct fw_ohci *ohci = context->ohci;
-        dma_addr_t payload_bus;
         int evt;
 
         if (last->transfer_status == 0)
@@ -1038,9 +1038,8 @@ static int handle_at_packet(struct context *context,
                 /* This packet was cancelled, just continue. */
                 return 1;
 
-        payload_bus = le32_to_cpu(last->data_address);
-        if (payload_bus != 0)
-                dma_unmap_single(ohci->card.device, payload_bus,
+        if (packet->payload_bus)
+                dma_unmap_single(ohci->card.device, packet->payload_bus,
                                  packet->payload_length, DMA_TO_DEVICE);
 
         evt = le16_to_cpu(last->transfer_status) & 0x1f;
@@ -1697,6 +1696,10 @@ static int ohci_cancel_packet(struct fw_card *card, struct fw_packet *packet)
         if (packet->ack != 0)
                 goto out;
 
+        if (packet->payload_bus)
+                dma_unmap_single(ohci->card.device, packet->payload_bus,
+                                 packet->payload_length, DMA_TO_DEVICE);
+
         log_ar_at_event('T', packet->speed, packet->header, 0x20);
         driver_data->packet = NULL;
         packet->ack = RCODE_CANCELLED;