linux-kernel - [PATCH 4.4 43/49] crypto: scatterwalk

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Message-Id: <20160814202304.858204489@linuxfoundation.org>
Date:	Sun, 14 Aug 2016 22:23:43 +0200
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Herbert Xu <herbert@...dor.apana.org.au>
Subject: [PATCH 4.4 43/49] crypto: scatterwalk - Fix test in scatterwalk_done

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Herbert Xu <herbert@...dor.apana.org.au>

commit 5f070e81bee35f1b7bd1477bb223a873ff657803 upstream.

When there is more data to be processed, the current test in
scatterwalk_done may prevent us from calling pagedone even when
we should.

In particular, if we're on an SG entry spanning multiple pages
where the last page is not a full page, we will incorrectly skip
calling pagedone on the second last page.

This patch fixes this by adding a separate test for whether we've
reached the end of a page.

Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 crypto/scatterwalk.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -72,7 +72,8 @@ static void scatterwalk_pagedone(struct
 
 void scatterwalk_done(struct scatter_walk *walk, int out, int more)
 {
-	if (!(scatterwalk_pagelen(walk) & (PAGE_SIZE - 1)) || !more)
+	if (!more || walk->offset >= walk->sg->offset + walk->sg->length ||
+	    !(walk->offset & (PAGE_SIZE - 1)))
 		scatterwalk_pagedone(walk, out, more);
 }
 EXPORT_SYMBOL_GPL(scatterwalk_done);