From: Stephen Hemminger <stephen@networkplumber.org>
Date: Mon, 10 Dec 2018 10:18:19 -0800
Patch-mainline: v4.20
Subject: uio_hv_generic: set callbacks on open
Git-commit: 5e3c420dcca53766dec57d5bf4df8eecdb953c03
References: fate#323887

This fixes the problem where uio application was unable to
use multple queues on restart. The root cause is that the callbacks
are cleared on disconnect. Change to setting up callbacks
everytime in open.

Fixes: cdfa835c6e5e ("uio_hv_generic: defer opening vmbus until first use")
Reported-by: Mohammed Gamal <mgamal@redhat.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Olaf Hering <ohering@suse.de>
---
 drivers/uio/uio_hv_generic.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
--- a/drivers/uio/uio_hv_generic.c
+++ b/drivers/uio/uio_hv_generic.c
@@ -204,9 +204,11 @@ hv_uio_open(struct uio_info *info, struct inode *inode)
 	if (atomic_inc_return(&pdata->refcnt) != 1)
 		return 0;
 
+	vmbus_set_chn_rescind_callback(dev->channel, hv_uio_rescind);
+	vmbus_set_sc_create_callback(dev->channel, hv_uio_new_channel);
+
 	ret = vmbus_connect_ring(dev->channel,
 				 hv_uio_channel_cb, dev->channel);
-
 	if (ret == 0)
 		dev->channel->inbound.ring_buffer->interrupt_mask = 1;
 	else
@@ -334,9 +336,6 @@ hv_uio_probe(struct hv_device *dev,
 		goto fail_close;
 	}
 
-	vmbus_set_chn_rescind_callback(channel, hv_uio_rescind);
-	vmbus_set_sc_create_callback(channel, hv_uio_new_channel);
-
 	ret = sysfs_create_bin_file(&channel->kobj, &ring_buffer_bin_attr);
 	if (ret)
 		dev_notice(&dev->device,