Re: [PATCH net-next v3 05/10] crypto: af_alg: Pin pages rather than ref'ing if appropriate

[Herbert Xu]

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@xxxxxxxxxx>
> cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
> cc: Eric Dumazet <edumazet@xxxxxxxxxx>
> cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> cc: Paolo Abeni <pabeni@xxxxxxxxxx>
> cc: Jens Axboe <axboe@xxxxxxxxx>
> cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> cc: linux-crypto@xxxxxxxxxxxxxxx
> cc: netdev@xxxxxxxxxxxxxxx
> ---
>  crypto/af_alg.c         | 10 +++++++---
>  include/crypto/if_alg.h |  1 +
>  2 files changed, 8 insertions(+), 3 deletions(-)

Acked-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
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