libceph: Partially revert changes to support MSG_SPLICE_PAGES

[platform/kernel/linux-rpi.git] / net / ceph / messenger_v2.c

diff --git a/net/ceph/messenger_v2.c b/net/ceph/messenger_v2.c
index 87ac970..1a888b8 100644 (file)
--- a/net/ceph/messenger_v2.c
+++ b/net/ceph/messenger_v2.c
@@ -117,38 +117,90 @@ static int ceph_tcp_recv(struct ceph_connection *con)
        return ret;
 }
 
+static int do_sendmsg(struct socket *sock, struct iov_iter *it)
+{
+       struct msghdr msg = { .msg_flags = CEPH_MSG_FLAGS };
+       int ret;
+
+       msg.msg_iter = *it;
+       while (iov_iter_count(it)) {
+               ret = sock_sendmsg(sock, &msg);
+               if (ret <= 0) {
+                       if (ret == -EAGAIN)
+                               ret = 0;
+                       return ret;
+               }
+
+               iov_iter_advance(it, ret);
+       }
+
+       WARN_ON(msg_data_left(&msg));
+       return 1;
+}
+
+static int do_try_sendpage(struct socket *sock, struct iov_iter *it)
+{
+       struct msghdr msg = { .msg_flags = CEPH_MSG_FLAGS };
+       struct bio_vec bv;
+       int ret;
+
+       if (WARN_ON(!iov_iter_is_bvec(it)))
+               return -EINVAL;
+
+       while (iov_iter_count(it)) {
+               /* iov_iter_iovec() for ITER_BVEC */
+               bvec_set_page(&bv, it->bvec->bv_page,
+                             min(iov_iter_count(it),
+                                 it->bvec->bv_len - it->iov_offset),
+                             it->bvec->bv_offset + it->iov_offset);
+
+               /*
+                * MSG_SPLICE_PAGES cannot properly handle pages with
+                * page_count == 0, we need to fall back to sendmsg if
+                * that's the case.
+                *
+                * Same goes for slab pages: skb_can_coalesce() allows
+                * coalescing neighboring slab objects into a single frag
+                * which triggers one of hardened usercopy checks.
+                */
+               if (sendpage_ok(bv.bv_page))
+                       msg.msg_flags |= MSG_SPLICE_PAGES;
+               else
+                       msg.msg_flags &= ~MSG_SPLICE_PAGES;
+
+               iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bv, 1, bv.bv_len);
+               ret = sock_sendmsg(sock, &msg);
+               if (ret <= 0) {
+                       if (ret == -EAGAIN)
+                               ret = 0;
+                       return ret;
+               }
+
+               iov_iter_advance(it, ret);
+       }
+
+       return 1;
+}
+
 /*
  * Write as much as possible.  The socket is expected to be corked,
  * so we don't bother with MSG_MORE here.
  *
  * Return:
- *  >0 - done, nothing (else) to write
+ *   1 - done, nothing (else) to write
  *   0 - socket is full, need to wait
  *  <0 - error
  */
 static int ceph_tcp_send(struct ceph_connection *con)
 {
-       struct msghdr msg = {
-               .msg_iter       = con->v2.out_iter,
-               .msg_flags      = CEPH_MSG_FLAGS,
-       };
        int ret;
 
-       if (WARN_ON(!iov_iter_is_bvec(&con->v2.out_iter)))
-               return -EINVAL;
-
-       if (con->v2.out_iter_sendpage)
-               msg.msg_flags |= MSG_SPLICE_PAGES;
-
        dout("%s con %p have %zu try_sendpage %d\n", __func__, con,
             iov_iter_count(&con->v2.out_iter), con->v2.out_iter_sendpage);
-
-       ret = sock_sendmsg(con->sock, &msg);
-       if (ret > 0)
-               iov_iter_advance(&con->v2.out_iter, ret);
-       else if (ret == -EAGAIN)
-               ret = 0;
-
+       if (con->v2.out_iter_sendpage)
+               ret = do_try_sendpage(con->sock, &con->v2.out_iter);
+       else
+               ret = do_sendmsg(con->sock, &con->v2.out_iter);
        dout("%s con %p ret %d left %zu\n", __func__, con, ret,
             iov_iter_count(&con->v2.out_iter));
        return ret;