Hi All, ib_unregister_device<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=ib_unregister_device>() is typically called as part of the rdma driver module unload for a given device. As part of execution of this function it loops through the following code:
ofed/drivers/inifiniband/core/device.c void ib_unregister_device<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=ib_unregister_device>(struct ib_device<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=ib_device> *device<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=device>) { : list_for_each_entry_reverse<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=list_for_each_entry_reverse>(client<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=client>, &client_list, list<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=list>) if (client<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=client>->remove) client<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=client>->remove(device<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=device>); : } For IB clients, client->remove(device) calls cma_remove_one() (ofed/drivers/inifiniband/core/cma.c) which ends up calling cma_process_remove(). cma_process_remove() calls wait_for_completion(&cma_dev->comp). Now wait_for_completion() can potentially cause the thread to sleep(). >From kern/kern_module.c: int module_unload<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=module_unload>(module_t<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=module_t> mod<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=mod>) { int error<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=error>; mtx_lock<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=mtx_lock>(&Giant<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=Giant>); error<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=error> = MOD_EVENT<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=MOD_EVENT>(mod<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=mod>, MOD_UNLOAD<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=MOD_UNLOAD>); mtx_unlock<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=mtx_unlock>(&Giant<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=Giant>); return (error<http://fxr.watson.org/fxr/ident?v=FREEBSD10;i=error>); } We see that module_unload() grabs the Gaint Lock prior to invoking UNLOAD. Isn't this a problem with cma_process_remove() or am I missing something? Thanks David S. ([email protected]<mailto:[email protected]>) _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[email protected]"
