linux-kernel - [PATCH] firewire: fw-ohci: fix DMA mapping for ar context

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Date:	Tue, 16 Oct 2007 19:25:10 +0200 (CEST)
From:	Stefan Richter <stefanr@...6.in-berlin.de>
To:	linux1394-devel@...ts.sourceforge.net
cc:	linux-kernel@...r.kernel.org,
	Kristian Høgsberg <krh@...hat.com>
Subject: [PATCH] firewire: fw-ohci: fix DMA mapping for ar context

The CPU must not touch the buffer after it was DMA-mapped.

Signed-off-by: Stefan Richter <stefanr@...6.in-berlin.de>
---
 drivers/firewire/fw-ohci.c |   12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

Index: linux/drivers/firewire/fw-ohci.c
===================================================================
--- linux.orig/drivers/firewire/fw-ohci.c
+++ linux/drivers/firewire/fw-ohci.c
@@ -253,12 +253,6 @@ static int ar_context_add_page(struct ar
 	if (ab == NULL)
 		return -ENOMEM;
 
-	ab_bus = dma_map_single(dev, ab, PAGE_SIZE, DMA_BIDIRECTIONAL);
-	if (dma_mapping_error(ab_bus)) {
-		free_page((unsigned long) ab);
-		return -ENOMEM;
-	}
-
 	memset(&ab->descriptor, 0, sizeof(ab->descriptor));
 	ab->descriptor.control        = cpu_to_le16(DESCRIPTOR_INPUT_MORE |
 						    DESCRIPTOR_STATUS |
@@ -269,7 +263,11 @@ static int ar_context_add_page(struct ar
 	ab->descriptor.res_count      = cpu_to_le16(PAGE_SIZE - offset);
 	ab->descriptor.branch_address = 0;
 
-	dma_sync_single_for_device(dev, ab_bus, PAGE_SIZE, DMA_BIDIRECTIONAL);
+	ab_bus = dma_map_single(dev, ab, PAGE_SIZE, DMA_BIDIRECTIONAL);
+	if (dma_mapping_error(ab_bus)) {
+		free_page((unsigned long) ab);
+		return -ENOMEM;
+	}
 
 	ctx->last_buffer->descriptor.branch_address = cpu_to_le32(ab_bus | 1);
 	ctx->last_buffer->next = ab;

-- 
Stefan Richter
-=====-=-=== =-=- =----
http://arcgraph.de/sr/

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