[PATCH AUTOSEL 4.20 003/105] pvcalls-front: read all data before closing the connection

[Sasha Levin]

From: Stefano Stabellini <sstabell...@kernel.org>

[ Upstream commit b79470b64fa9266948d1ce8d825ced94c4f63293 ]

When a connection is closing in_error is set to ENOTCONN. There could
still be outstanding data on the ring left by the backend. Before
closing the connection on the frontend side, drain the ring.

Signed-off-by: Stefano Stabellini <stefa...@xilinx.com>
Reviewed-by: Boris Ostrovsky <boris.ostrov...@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrov...@oracle.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/xen/pvcalls-front.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 77224d8f3e6f..e5d95aab2cb8 100644
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -560,15 +560,13 @@ static int __read_ring(struct pvcalls_data_intf *intf,
        error = intf->in_error;
        /* get pointers before reading from the ring */
        virt_rmb();
-       if (error < 0)
-               return error;
 
        size = pvcalls_queued(prod, cons, array_size);
        masked_prod = pvcalls_mask(prod, array_size);
        masked_cons = pvcalls_mask(cons, array_size);
 
        if (size == 0)
-               return 0;
+               return error ?: size;
 
        if (len > size)
                len = size;
-- 
2.19.1