On Fri, 18 Apr 2025 at 23:06, Joanne Koong <joannelkoong@xxxxxxxxx> wrote: > > Use a bitfield for tracking initialized, blocked, aborted, and io_uring > state of the fuse connection. Track connected state using a bool instead > of an unsigned. > > On a 64-bit system, this shaves off 16 bytes from the size of struct > fuse_conn. > > No functional changes. Not sure about that. AFAIK aligned int or long is supposed to be independent from neighboring fields on all architectures. But that's definitely not true of bitfields and I'm not sure about bool. Maybe READ_ONCE()/WRITE_ONCE() make accessing bool safe, but I haven't found any documentation about that. Previous rule about bitfields in fuse_conn have been that they are either - only set at INIT reply time, or - losing a setting due to a race is a non-issue The new ones are not so clear cut, so it definitely needs some more explanation why they are safe (if they are safe). Thanks, Miklos
