pvcalls-front: don't return error when the ring is full

[ Upstream commit d90a1ca60a1eccb4383fe203c76223ab4c0799ed ]

When the ring is full, size == array_size. It is not an error condition,
so simply return 0 instead of an error.

Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c
index 3a144eecb6a728f639cbb82728d87b4fb993ac70..d7438fdc57061ef9b1479e4e39fc88540e1f5cd3 100644 (file)
--- a/drivers/xen/pvcalls-front.c
+++ b/drivers/xen/pvcalls-front.c
@@ -504,8 +504,10 @@ static int __write_ring(struct pvcalls_data_intf *intf,
        virt_mb();
 
        size = pvcalls_queued(prod, cons, array_size);
-       if (size >= array_size)
+       if (size > array_size)
                return -EINVAL;
+       if (size == array_size)
+               return 0;
        if (len > array_size - size)
                len = array_size - size;