On Tue, Oct 21, 2025 at 09:15:36AM -0300, Jason Gunthorpe wrote: > On Tue, Oct 21, 2025 at 04:49:59AM +0000, Tzung-Bi Shih wrote: > > > I didn't get the idea. With a mutex, how to handle the opening files? > > > > Are they something like: (?) > > - Maintain a list for opening files in both .open() and .release(). > > - In misc_deregister_sync(), traverse the list, do something (what?), and > > wait for the userspace programs close the files. > > You don't need any list, we don't want to close files. > > Something like this, it is very simple. You can replace the rwsem with > a srcu. srcu gives faster read locking but much slower sync. > > [...]
I see. The idea is basically the same but don't use revocable at all. I was misunderstanding about the "sync" we were discussing for misc_deregister_sync(). The "sync", is analogous to synchronize_srcu() of revocable_provider_revoke() in the revocable version [1], doesn't wait for closing all opened files. [1] https://lore.kernel.org/chrome-platform/aPT-7TTgW_Xop99j@tzungbi-laptop/
