uio_hv_generic: Set event for all channels on the device

uio_hv_generic: Set event for all channels on the device

commit d062463edf1770427dc2d637df4088df4835aa47 upstream.

Hyper-V may offer a non latency sensitive device with subchannels without
monitor bit enabled. The decision is entirely on the Hyper-V host not
configurable within guest.

When a device has subchannels, also signal events for the subchannel
if its monitor bit is disabled.

This patch also removes the memory barrier when monitor bit is enabled
as it is not necessary. The memory barrier is only needed between
setting up interrupt mask and calling vmbus_set_event() when monitor
bit is disabled.

Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Link: https://lore.kernel.org/r/1741644721-20389-1-git-send-email-longli@linuxonhyperv.com
Fixes: b15b7d2a1b09 ("uio_hv_generic: Let userspace take care of interrupt mask")
Closes: https://bugs.debian.org/1120602
Signed-off-by: Naman Jain <namjain@linux.microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>