linux-kernel - [PATCH] async_tx: use memchr

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Date:	Sun, 28 Oct 2012 00:49:33 +0900
From:	Akinobu Mita <akinobu.mita@...il.com>
To:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org
Cc:	Akinobu Mita <akinobu.mita@...il.com>,
	Vinod Koul <vinod.koul@...el.com>, Dan Williams <djbw@...com>
Subject: [PATCH] async_tx: use memchr_inv

Use memchr_inv() to check the specified page is filled with zero.

Signed-off-by: Akinobu Mita <akinobu.mita@...il.com>
Cc: Vinod Koul <vinod.koul@...el.com>
Cc: Dan Williams <djbw@...com>
---
 crypto/async_tx/async_xor.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c
index 154cc84..8ade0a0 100644
--- a/crypto/async_tx/async_xor.c
+++ b/crypto/async_tx/async_xor.c
@@ -230,9 +230,7 @@ EXPORT_SYMBOL_GPL(async_xor);
 
 static int page_is_zero(struct page *p, unsigned int offset, size_t len)
 {
-	char *a = page_address(p) + offset;
-	return ((*(u32 *) a) == 0 &&
-		memcmp(a, a + 4, len - 4) == 0);
+	return !memchr_inv(page_address(p) + offset, 0, len);
 }
 
 static inline struct dma_chan *
-- 
1.7.11.7

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