NTB: correct dmaengine_get/put usage

dmaengine_get() causes the initialization of the per-cpu channel tables.
It needs to be called prior to dma_find_channel().

Initial version by Dan Williams <dan.j.williams@intel.com>

Signed-off-by: Jon Mason <jon.mason@intel.com>

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 7010f23..172501d 100644 (file)
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -1419,11 +1419,12 @@ ntb_transport_create_queue(void *data, struct pci_dev *pdev,
        qp->tx_handler = handlers->tx_handler;
        qp->event_handler = handlers->event_handler;
 
+       dmaengine_get();
        qp->dma_chan = dma_find_channel(DMA_MEMCPY);
-       if (!qp->dma_chan)
+       if (!qp->dma_chan) {
+               dmaengine_put();
                dev_info(&pdev->dev, "Unable to allocate DMA channel, using CPU instead\n");
-       else
-               dmaengine_get();
+       }
 
        for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) {
                entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC);
@@ -1464,6 +1465,8 @@ err2:
 err1:
        while ((entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q)))
                kfree(entry);
+       if (qp->dma_chan)
+               dmaengine_put();
        set_bit(free_queue, &nt->qp_bitmap);
 err:
        return NULL;