@@ -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);
@@ -59,6 +59,7 @@ struct af_alg_sgl {
struct scatterlist sg[ALG_MAX_PAGES + 1];
struct page *pages[ALG_MAX_PAGES];
unsigned int npages;
+ bool need_unpin;
};
/* TX SGL entry */
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: linux-crypto@vger.kernel.org --- crypto/af_alg.c | 10 +++++++--- include/crypto/if_alg.h | 1 + 2 files changed, 8 insertions(+), 3 deletions(-)