On Thu, Sep 07, 2017 at 03:42:25PM -0300, Gustavo Padovan wrote: > From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx> > > Rename __close_fd() to close_fd() and export it to be able close files > in modules using file descriptors. > > The usecase that motivates this change happens in V4L2 where we send > events to userspace with a fd that has file installed in it. But if for > some reason we have to cancel the video stream we need to close the files > that haven't been shared with userspace yet. Thus the export of > close_fd() becomes necessary. > > fd_install() happens when we call an ioctl to queue a buffer, but we only > share the fd with userspace later, and that may happen in a kernel thread > instead. NAK. As soon as the reference is in descriptor table, you *can't* do anything to it. This "sharing" part is complete BS - being _told_ that descriptor is there does not matter at all. That descriptor might be hit with dup2() as soon as fd_install() has happened. Or be closed, or any number of other things. You can not take it back. Once fd_install() is done, it's fucking done, period. If V4L2 requires removing it from descriptor table, it's a shitty API and needs to be fixed. Again, NAK.
