[PATCH 2/6] crypto: Fix scatterwalk_done() test.

[PATCH 2/6] crypto: Fix scatterwalk_done() test.

[David Miller]

We are done with the scattergather entry when the walk offset goes
past sg->offset + sg->length, not when it crosses a page boundary.

There is a similarly queer test in the second half of
scatterwalk_pagedone() that probably needs some scrutiny.

Signed-off-by: David S. Miller <davem@davemloft.net>
---
 crypto/scatterwalk.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 3de89a4..b3acf4f 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -68,7 +68,7 @@ static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
 
 void scatterwalk_done(struct scatter_walk *walk, int out, int more)
 {
-	if (!offset_in_page(walk->offset) || !more)
+	if (walk->offset >= walk->sg->offset + walk->sg->length || !more)
 		scatterwalk_pagedone(walk, out, more);
 }
 EXPORT_SYMBOL_GPL(scatterwalk_done);
-- 
1.7.0.4

Re: [PATCH 2/6] crypto: Fix scatterwalk_done() test.

[Herbert Xu]

On Mon, May 17, 2010 at 10:22:37PM -0700, David Miller wrote:
> 
> We are done with the scattergather entry when the walk offset goes
> past sg->offset + sg->length, not when it crosses a page boundary.

Thanks for catching this!

> There is a similarly queer test in the second half of
> scatterwalk_pagedone() that probably needs some scrutiny.

I double-checked that one but can't see any problems yet.
 
> diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
> index 3de89a4..b3acf4f 100644
> --- a/crypto/scatterwalk.c
> +++ b/crypto/scatterwalk.c
> @@ -68,7 +68,7 @@ static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
>  
>  void scatterwalk_done(struct scatter_walk *walk, int out, int more)
>  {
> -	if (!offset_in_page(walk->offset) || !more)
> +	if (walk->offset >= walk->sg->offset + walk->sg->length || !more)
>  		scatterwalk_pagedone(walk, out, more);

I think we need to keep the original test as well as otherwise
if we hit a page boundary while the sg spans over a page (that
can happen with a linearised jumbo skb->head for example) then
we'd be screwed.

So I'm going to commit this patch instead.  Let me know if you
see any other issues with it.

diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 3de89a4..41e529a 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -68,7 +68,7 @@ static void scatterwalk_pagedone(struct scatter_walk *walk, int out,
 
 void scatterwalk_done(struct scatter_walk *walk, int out, int more)
 {
-	if (!offset_in_page(walk->offset) || !more)
+	if (!(scatterwalk_pagelen(walk) & (PAGE_SIZE - 1)) || !more)
 		scatterwalk_pagedone(walk, out, more);
 }
 EXPORT_SYMBOL_GPL(scatterwalk_done);

Thanks,
-- 
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Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
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Re: [PATCH 2/6] crypto: Fix scatterwalk_done() test.

[David Miller]

From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Wed, 19 May 2010 14:05:13 +1000

> So I'm going to commit this patch instead.  Let me know if you
> see any other issues with it.

Looks good:

Acked-by: David S. Miller <davem@davemloft.net>