diff options
| author | David Howells <dhowells@redhat.com> | 2023-06-06 14:08:51 +0100 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2023-06-08 13:42:34 +0200 |
| commit | f9e7a5fa51fbb6fcb9c1c7e2c89dd7df9e7fe253 (patch) | |
| tree | 6d2a6e60bbd02b449b4e2fa68e028e1d1f25a57a /crypto | |
| parent | f5f82cd18732d828bcd1ec308c4e8c55012e84b0 (diff) | |
crypto: af_alg: Pin pages rather than ref'ing if appropriate
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
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/af_alg.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 5f7252a5b7b4..7caff10df643 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -533,14 +533,17 @@ static const struct net_proto_family alg_family = { int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len) { + struct page **pages = sgl->pages; size_t off; ssize_t n; int npages, i; - n = iov_iter_get_pages2(iter, sgl->pages, len, ALG_MAX_PAGES, &off); + n = iov_iter_extract_pages(iter, &pages, len, ALG_MAX_PAGES, 0, &off); if (n < 0) return n; + sgl->need_unpin = iov_iter_extract_will_pin(iter); + npages = DIV_ROUND_UP(off + n, PAGE_SIZE); if (WARN_ON(npages == 0)) return -EINVAL; @@ -573,8 +576,9 @@ void af_alg_free_sg(struct af_alg_sgl *sgl) { int i; - for (i = 0; i < sgl->npages; i++) - put_page(sgl->pages[i]); + if (sgl->need_unpin) + for (i = 0; i < sgl->npages; i++) + unpin_user_page(sgl->pages[i]); } EXPORT_SYMBOL_GPL(af_alg_free_sg); |