Drivers: hv: vmbus: Fix rescind handling in uio_hv_generic

commit 6fd28941447bf2c8ca0f26fda612a1cabc41663f upstream.

Rescind offer handling relies on rescind callbacks for some of the
resources cleanup, if they are registered. It does not unregister
vmbus device for the primary channel closure, when callback is
registered. Without it, next onoffer does not come, rescind flag
remains set and device goes to unusable state.

Add logic to unregister vmbus for the primary channel in rescind callback
to ensure channel removal and relid release, and to ensure that next
onoffer can be received and handled properly.

Cc: stable@vger.kernel.org
Fixes: ca3cda6fcf1e ("uio_hv_generic: add rescind support")
Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Link: https://lore.kernel.org/r/20240829071312.1595-3-namjain@linux.microsoft.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index edbb38f6956b94514bcf93188df1bc0a6185f25f..756aebf324735f8740348acdf7dc507b8deb4137 100644 (file)
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1962,6 +1962,7 @@ void vmbus_device_unregister(struct hv_device *device_obj)
         */
        device_unregister(&device_obj->device);
 }
+EXPORT_SYMBOL_GPL(vmbus_device_unregister);
 
 #ifdef CONFIG_ACPI
 /*

diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
index 94a1fe82e4d519046badae30487dc4a3665587d9..a2c7abf8c289efa8b4a0f132a0e4f322ce126bf6 100644 (file)
--- a/drivers/uio/uio_hv_generic.c
+++ b/drivers/uio/uio_hv_generic.c
@@ -119,6 +119,14 @@ static void hv_uio_rescind(struct vmbus_channel *channel)
 
        /* Wake up reader */
        uio_event_notify(&pdata->info);
+
+       /*
+        * With rescind callback registered, rescind path will not unregister the device
+        * from vmbus when the primary channel is rescinded.
+        * Without it, rescind handling is incomplete and next onoffer msg does not come.
+        * Unregister the device from vmbus here.
+        */
+       vmbus_device_unregister(channel->device_obj);
 }
 
 /* Sysfs API to allow mmap of the ring buffers