Ack On Wed, Apr 19, 2023 at 7:17 PM Kui Liu <kui....@acronis.com> wrote: > > It looks like the new API iov_iter_get_pages is not safe for use > when trying to get a page from a bvec to be sent by kernel_sendpage(). > So just revert back our own implentation where we check the page > before making get_page(), if the page can't be sendpage, fall back > to copy mode. > > Affects: #PSBM-146821, #PSBM-146846 > https://jira.vzint.dev/browse/PSBM-146821 > https://jira.vzint.dev/browse/PSBM-146846 > Signed-off-by: Liu Kui <kui....@acronis.com> > --- > fs/fuse/kio/pcs/pcs_sock_io.c | 26 ++++++++++++++++++++------ > 1 file changed, 20 insertions(+), 6 deletions(-) > > diff --git a/fs/fuse/kio/pcs/pcs_sock_io.c b/fs/fuse/kio/pcs/pcs_sock_io.c > index 552b82ab398b..710940eafa34 100644 > --- a/fs/fuse/kio/pcs/pcs_sock_io.c > +++ b/fs/fuse/kio/pcs/pcs_sock_io.c > @@ -143,16 +143,30 @@ static int do_send_one_seg(struct socket *sock, struct > iov_iter *it, size_t left > } > > if (iov_iter_is_bvec(it)) { > - /* Zerocopy */ > size_t offset; > ssize_t len; > struct page *page; > > - len = iov_iter_get_pages(it, &page, size, 1, &offset); > - BUG_ON(len <= 0); > - > - ret = kernel_sendpage(sock, page, offset, len, flags); > - put_page(page); > + /* Only support single page bvec here */ > + page = it->bvec->bv_page; > + offset = it->bvec->bv_offset + it->iov_offset; > + len = min(size, it->bvec->bv_len - it->iov_offset); > + > + if (sendpage_ok(page)) { > + /* Zero copy */ > + get_page(page); > + ret = kernel_sendpage(sock, page, offset, len, flags); > + put_page(page); > + } else { > + /* Fall back to copy mode */ > + struct msghdr msg = { .msg_flags = flags }; > + struct kvec kv; > + > + kv.iov_base = kmap(page) + offset; > + kv.iov_len = len; > + ret = kernel_sendmsg(sock, &msg, &kv, 1, size); > + kunmap(page); > + } > } > > out: > -- > 2.32.0 (Apple Git-132) > > _______________________________________________ > Devel mailing list > Devel@openvz.org > https://lists.openvz.org/mailman/listinfo/devel
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