From: Dexuan Cui <decui@xxxxxxxxxxxxx> Sent: Saturday, January 25, 2020 11:54 AM > > Add util_pre_suspend() and util_pre_resume() for some hv_utils devices > (e.g. kvp/vss/fcopy), because they need special handling before > util_suspend() calls vmbus_close(). > > For kvp, all the possible pending work items should be cancelled. > > For vss and fcopy, some extra clean-up needs to be done, i.e. fake a > THAW message for hv_vss_daemon and fake a CANCEL_FCOPY message for > hv_fcopy_daemon, otherwise when the VM resums back, the daemons > can end up in an inconsistent state (i.e. the file systems are > frozen but will never be thawed; the file transmitted via fcopy > may not be complete). Note: there is an extra patch for the daemons: > "Tools: hv: Reopen the devices if read() or write() returns errors", > because the hv_utils driver can not guarantee the whole transaction > finishes completely once util_suspend() starts to run (at this time, > all the userspace processes are frozen). > > util_probe() disables channel->callback_event to avoid the race with > the channel callback. > > Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx> > > --- > Changes in v2: > Handles fcopy/vss specially to avoid possible inconsistent states. > > Changes in v3 (I addressed Michael's comments): > Removed unneeded blank lines. > Simplified the error handling logic by allocating memory earlier. > Added a comment before util_suspend(): when we're in the function, > all the userspace processes have been frozen. > > drivers/hv/hv_fcopy.c | 54 +++++++++++++++++++++++++++++++++- > drivers/hv/hv_kvp.c | 43 +++++++++++++++++++++++++-- > drivers/hv/hv_snapshot.c | 55 ++++++++++++++++++++++++++++++++-- > drivers/hv/hv_util.c | 62 ++++++++++++++++++++++++++++++++++++++- > drivers/hv/hyperv_vmbus.h | 6 ++++ > include/linux/hyperv.h | 2 ++ > 6 files changed, 216 insertions(+), 6 deletions(-) > Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
