On Wed, 2021-01-20 at 16:52 -0700, Shuah Khan wrote: > Hi Anna and Trond, > > I came across the following while reviewing atomic_inc_return() > usages > that cast return value to unsigned > > rpc_xprt_debugfs_register()'s atomic_inc_return() usage looks a bit > odd. > > - cur_id isn't initialized > - id = (unsigned int)atomic_inc_return(&cur_id); > > Please note that id is int. Is it expected that cur_id could > overflow? > Is there a maximum limit for this value? > Yes, we do expect cur_id to eventually overflow (once you have created 2 billion RPC client instances), however the atomic increment operations are expected to handle this correctly according to the maintainers (I already asked them in a different context). Furthermore, the code itself doesn't care about strict sequentiality. All it wants from the counter is uniqueness, with that uniqueness condition actually being enforced by the subsequent debugfs_create_file() call. IOW: I don't think this is a real problem. -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx
