On Jul 17, 2014, at 11:01 AM, Steve Wise <sw...@opengridcomputing.com> wrote:
> > > On 7/17/2014 9:01 AM, Devesh Sharma wrote: >> If verndor driver is attempted for removal while xprtrdma still has an >> active mount, the removal of driver may never complete and can cause >> unseen races or in worst case system crash. >> >> To solve this, xprtrdma module should get reference of struct ib_device >> structure for every mount. Reference is taken after local device address >> resolution is completed successfuly. >> >> reference to the struct ib_device pointer is put just before cm_id >> destruction. >> >> Signed-off-by: Devesh Sharma <devesh.sha...@emulex.com> > > This seems like an issue with the rdma-cm or rdma core, not xprtrdma. Good point. I was wondering if svcrdma might have a similar issue. Infrequently I see a hang during shutdown that appears to be related to the ordering of removal of one of the RDMA modules, but I’ve never had time to chase it. See also: https://bugzilla.linux-nfs.org/show_bug.cgi?id=252 > I see that user rdma applications cause a ref on the provider module here in > ib_uverbs_open(): > > if (!try_module_get(dev->ib_dev->owner)) { > ret = -ENODEV; > goto err; > > > Maybe kernel applications that allocate device resources should cause a ref > on the provider's module. > > Sean/Roland, is there some history here as to how rdma provider module > removal should be handled? > > Steve. -- Chuck Lever chuck[dot]lever[at]oracle[dot]com -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
