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authorDavid Howells <dhowells@redhat.com>2023-06-06 16:08:51 +0300
committerPaolo Abeni <pabeni@redhat.com>2023-06-08 14:42:34 +0300
commitf9e7a5fa51fbb6fcb9c1c7e2c89dd7df9e7fe253 (patch)
tree6d2a6e60bbd02b449b4e2fa68e028e1d1f25a57a /crypto
parentf5f82cd18732d828bcd1ec308c4e8c55012e84b0 (diff)
downloadlinux-f9e7a5fa51fbb6fcb9c1c7e2c89dd7df9e7fe253.tar.xz
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.c10
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);