On 01/26, Christian Brauner wrote: > > > --- a/include/uapi/linux/pidfd.h > > +++ b/include/uapi/linux/pidfd.h > > @@ -7,6 +7,7 @@ > > #include <linux/fcntl.h> > > > > /* Flags for pidfd_open(). */ > > -#define PIDFD_NONBLOCK O_NONBLOCK > > +#define PIDFD_NONBLOCK O_NONBLOCK > > +#define PIDFD_THREAD O_EXCL // or anything else not used by anon_inode's > > I like it! > > The only request I would have is to not alias O_EXCL and PIDFD_THREAD. > Because it doesn't map as clearly as NONBLOCK did. But it would be nice to have PIDFD_THREAD in file->f_flags. Where else can we keep it? I chose O_EXCL because it can only be used at open time, it can never be used or changed after anon_inode_getfile(), so we can safely do pidfd_file->f_flags |= PIDFD_THREAD; in __pidfd_prepare() and then check in pidfd_poll/pidfd_send_signal. What do you suggest instead? Oleg.
