[PATCH AUTOSEL 4.14 02/34] pvcalls-back: set -ENOTCONN in pvcalls_conn_back_read

Sasha Levin
2019-02-13T02:40:09Z

From: Stefano Stabellini <sstabellini@kernel.org>

[ Upstream commit e6587cdbd732eacb4c7ce592ed46f7bbcefb655f ]

When a connection is closing we receive on pvcalls_sk_state_change
notification. Instead of setting the connection as closed immediately
(-ENOTCONN), let's read one more time from it: pvcalls_conn_back_read
will set the connection as closed when necessary.

That way, we avoid races between pvcalls_sk_state_change and
pvcalls_back_ioworker.

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>
---
drivers/xen/pvcalls-back.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
index 169293c25a91..7185ebb63bd5 100644
--- a/drivers/xen/pvcalls-back.c
+++ b/drivers/xen/pvcalls-back.c
@@ -164,9 +164,10 @@ static void pvcalls_conn_back_read(void *opaque)

/* write the data, then modify the indexes */
virt_wmb();
- if (ret < 0)
+ if (ret < 0) {
+ atomic_set(&map->read, 0);
intf->in_error = ret;
- else
+ } else
intf->in_prod = prod + ret;
/* update the indexes, then notify the other end */
virt_wmb();
@@ -296,7 +297,7 @@ static void pvcalls_sk_state_change(struct sock *sock)
return;

intf = map->ring;
- intf->in_error = -ENOTCONN;
+ atomic_inc(&map->read);
notify_remote_via_irq(map->irq);
}

--
2.19.1