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Date:   Wed, 7 Jun 2023 16:40:36 +0800
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     David Howells <dhowells@redhat.com>
Cc:     netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
        David Ahern <dsahern@kernel.org>,
        Matthew Wilcox <willy@infradead.org>,
        Jens Axboe <axboe@kernel.dk>, linux-crypto@vger.kernel.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next v3 05/10] crypto: af_alg: Pin pages rather than
 ref'ing if appropriate
Message-ID: <ZIBChFDNAIstvS6l@gondor.apana.org.au>
References: <20230606130856.1970660-1-dhowells@redhat.com>
 <20230606130856.1970660-6-dhowells@redhat.com>
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On Tue, Jun 06, 2023 at 02:08:51PM +0100, David Howells wrote:
> Convert AF_ALG to use iov_iter_extract_pages() instead of
> iov_iter_get_pages().  This will pin pages or leave them unaltered rather
> than getting a ref on them as appropriate to the iterator.
> 
> The pages need to be pinned for DIO-read rather than having refs taken on
> them to prevent VM copy-on-write from malfunctioning during a concurrent
> fork() (the result of the I/O would otherwise end up only visible to the
> child process and not the parent).
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Herbert Xu <herbert@gondor.apana.org.au>
> cc: "David S. Miller" <davem@davemloft.net>
> cc: Eric Dumazet <edumazet@google.com>
> cc: Jakub Kicinski <kuba@kernel.org>
> cc: Paolo Abeni <pabeni@redhat.com>
> cc: Jens Axboe <axboe@kernel.dk>
> cc: Matthew Wilcox <willy@infradead.org>
> cc: linux-crypto@vger.kernel.org
> cc: netdev@vger.kernel.org
> ---
>  crypto/af_alg.c         | 10 +++++++---
>  include/crypto/if_alg.h |  1 +
>  2 files changed, 8 insertions(+), 3 deletions(-)

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt