From 842fa69f3e0c9a178b294e7af7c07f4c9d9e7af2 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@linux-foundation.org>
Date: Wed, 2 Nov 2011 13:39:33 -0700
Subject: [PATCH] include/linux/dma-mapping.h: add dma_zalloc_coherent()
Lots of driver code does a dma_alloc_coherent() and then zeroes out the
memory with a memset. Make it easy for them.
Cc: Alexandre Bounine <alexandre.bounine@idt.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
Documentation/DMA-API.txt | 7 +++++++
include/linux/dma-mapping.h | 10 ++++++++++
2 files changed, 17 insertions(+)
diff --git a/Documentation/DMA-API.txt b/Documentation/DMA-API.txt
index fe2326906610d1..66bd97a95f10e1 100644
--- a/Documentation/DMA-API.txt
+++ b/Documentation/DMA-API.txt
@@ -50,6 +50,13 @@ specify the GFP_ flags (see kmalloc) for the allocation (the
implementation may choose to ignore flags that affect the location of
the returned memory, like GFP_DMA).
+void *
+dma_zalloc_coherent(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t flag)
+
+Wraps dma_alloc_coherent() and also zeroes the returned memory if the
+allocation attempt succeeded.
+
void
dma_free_coherent(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_handle)
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 347fdc32177a66..be86ae13893fce 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -1,6 +1,7 @@
#ifndef _LINUX_DMA_MAPPING_H
#define _LINUX_DMA_MAPPING_H
+#include <linux/string.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/dma-attrs.h>
@@ -117,6 +118,15 @@ static inline int dma_set_seg_boundary(struct device *dev, unsigned long mask)
return -EIO;
}
+static inline void *dma_zalloc_coherent(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t flag)
+{
+ void *ret = dma_alloc_coherent(dev, size, dma_handle, flag);
+ if (ret)
+ memset(ret, 0, size);
+ return ret;
+}
+
#ifdef CONFIG_HAS_DMA
static inline int dma_get_cache_alignment(void)
{
--
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