virtiofsd: Remove useless code about send_notify_iov

The 'ch' will be NULL in the following stack:
send_notify_iov()->fuse_send_msg()->virtio_send_msg(), and
this may lead to NULL pointer dereferenced in virtio_send_msg().
But send_notify_iov() was never called, so remove the useless code
about send_notify_iov() to fix this problem.

Signed-off-by: Alex Chen <alex.chen@huawei.com>
Message-Id: <20201214121615.29967-1-alex.chen@huawei.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

tools/virtiofsd/fuse_lowlevel.c

@@ -2143,104 +2143,6 @@ static void do_destroy(fuse_req_t req, fuse_ino_t nodeid,
     send_reply_ok(req, NULL, 0);
 }
 
-static int send_notify_iov(struct fuse_session *se, int notify_code,
-                           struct iovec *iov, int count)
-{
-    struct fuse_out_header out = {
-        .error = notify_code,
-    };
-
-    if (!se->got_init) {
-        return -ENOTCONN;
-    }
-
-    iov[0].iov_base = &out;
-    iov[0].iov_len = sizeof(struct fuse_out_header);
-
-    return fuse_send_msg(se, NULL, iov, count);
-}
-
-int fuse_lowlevel_notify_poll(struct fuse_pollhandle *ph)
-{
-    if (ph != NULL) {
-        struct fuse_notify_poll_wakeup_out outarg = {
-            .kh = ph->kh,
-        };
-        struct iovec iov[2];
-
-        iov[1].iov_base = &outarg;
-        iov[1].iov_len = sizeof(outarg);
-
-        return send_notify_iov(ph->se, FUSE_NOTIFY_POLL, iov, 2);
-    } else {
-        return 0;
-    }
-}
-
-int fuse_lowlevel_notify_inval_inode(struct fuse_session *se, fuse_ino_t ino,
-                                     off_t off, off_t len)
-{
-    struct fuse_notify_inval_inode_out outarg = {
-        .ino = ino,
-        .off = off,
-        .len = len,
-    };
-    struct iovec iov[2];
-
-    if (!se) {
-        return -EINVAL;
-    }
-
-    iov[1].iov_base = &outarg;
-    iov[1].iov_len = sizeof(outarg);
-
-    return send_notify_iov(se, FUSE_NOTIFY_INVAL_INODE, iov, 2);
-}
-
-int fuse_lowlevel_notify_inval_entry(struct fuse_session *se, fuse_ino_t parent,
-                                     const char *name, size_t namelen)
-{
-    struct fuse_notify_inval_entry_out outarg = {
-        .parent = parent,
-        .namelen = namelen,
-    };
-    struct iovec iov[3];
-
-    if (!se) {
-        return -EINVAL;
-    }
-
-    iov[1].iov_base = &outarg;
-    iov[1].iov_len = sizeof(outarg);
-    iov[2].iov_base = (void *)name;
-    iov[2].iov_len = namelen + 1;
-
-    return send_notify_iov(se, FUSE_NOTIFY_INVAL_ENTRY, iov, 3);
-}
-
-int fuse_lowlevel_notify_delete(struct fuse_session *se, fuse_ino_t parent,
-                                fuse_ino_t child, const char *name,
-                                size_t namelen)
-{
-    struct fuse_notify_delete_out outarg = {
-        .parent = parent,
-        .child = child,
-        .namelen = namelen,
-    };
-    struct iovec iov[3];
-
-    if (!se) {
-        return -EINVAL;
-    }
-
-    iov[1].iov_base = &outarg;
-    iov[1].iov_len = sizeof(outarg);
-    iov[2].iov_base = (void *)name;
-    iov[2].iov_len = namelen + 1;
-
-    return send_notify_iov(se, FUSE_NOTIFY_DELETE, iov, 3);
-}
-
 int fuse_lowlevel_notify_store(struct fuse_session *se, fuse_ino_t ino,
                                off_t offset, struct fuse_bufvec *bufv)
 {