linux-kernel - [PATCH 5/9] NTB: correct dmaengine

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Message-Id: <1384993290-10107-6-git-send-email-jon.mason@intel.com>
Date:	Wed, 20 Nov 2013 17:21:26 -0700
From:	Jon Mason <jon.mason@...el.com>
To:	linux-kernel@...r.kernel.org
Subject: [PATCH 5/9] 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@...el.com>

Signed-off-by: Jon Mason <jon.mason@...el.com>
---
 drivers/ntb/ntb_transport.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 7010f23..172501d 100644
--- 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;
-- 
1.7.9.5

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