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. What do you mean? A file descriptor is shared with userspace as soon as it's installed in the fdtable by fd_install(). As soon as it's there, another thread can use it (or close it, duplicate it, etc.), even before the syscall that installed it returns... Eric
