On 12/8/19 3:51 PM, Mike Christie wrote:
This fixes a regression added with:
commit e9e006f5fcf2bab59149cb38a48a4817c1b538b4 Author: Mike Christie mchristi@redhat.com Date: Sun Aug 4 14:10:06 2019 -0500
nbd: fix max number of supported devswhere we can deadlock during device shutdown. The problem occurs if the recv_work's nbd_config_put occurs after nbd_start_device_ioctl has returned and the userspace app has droppped its reference via closing the device and running nbd_release. The recv_work nbd_config_put call would then drop the refcount to zero and try to destroy the config which would try to do destroy_workqueue from the recv work.
This patch just has nbd_start_device_ioctl do a flush_workqueue when it wakes so we know after the ioctl returns running works have exited. This also fixes a possible race where we could try to reuse the device while old recv_works are still running.
Applied, thanks Mike.