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>

diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index 46610b0..ab9c01e 100644 (file)
--- 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;

diff --git a/drivers/firewire/fw-transaction.c b/drivers/firewire/fw-transaction.c
index 022ac4f..2884f87 100644 (file)
--- a/drivers/firewire/fw-transaction.c
+++ b/drivers/firewire/fw-transaction.c
@@ -207,6 +207,7 @@ fw_fill_request(struct fw_packet *packet, int tcode, int tlabel,
        packet->speed = speed;
        packet->generation = generation;
        packet->ack = 0;
+       packet->payload_bus = 0;
 }
 
 /**
@@ -581,6 +582,8 @@ fw_fill_response(struct fw_packet *response, u32 *request_header,
                BUG();
                return;
        }
+
+       response->payload_bus = 0;
 }
 EXPORT_SYMBOL(fw_fill_response);
 

diff --git a/drivers/firewire/fw-transaction.h b/drivers/firewire/fw-transaction.h
index aed7dbb..839466f 100644 (file)
--- a/drivers/firewire/fw-transaction.h
+++ b/drivers/firewire/fw-transaction.h
@@ -27,6 +27,7 @@
 #include <linux/list.h>
 #include <linux/spinlock_types.h>
 #include <linux/timer.h>
+#include <linux/types.h>
 #include <linux/workqueue.h>
 
 #define TCODE_IS_READ_REQUEST(tcode)   (((tcode) & ~1) == 4)
@@ -153,6 +154,7 @@ struct fw_packet {
        size_t header_length;
        void *payload;
        size_t payload_length;
+       dma_addr_t payload_bus;
        u32 timestamp;
 
        /*