On Mon, Nov 19, 2018 at 01:02:06PM -0600, Eric W. Biederman wrote: > Christian Brauner <christian@xxxxxxxxxx> writes: > > > On Mon, Nov 19, 2018 at 07:59:24AM -0800, Daniel Colascione wrote: > >> You never addressed my comment on the previous patch about your use of > > > > Sorry, that thread exploded so quickly that I might have missed it. > > > >> private_data here. Why can't you use the struct pid reference that's > >> already in the inode? > > > > If that's what people prefer we can probably use that. There was > > precedent for stashing away such data in fs/proc/base.c already for > > various other things including user namespaces and struct mm so I > > followed this model. A prior version of my patch (I didn't send out) did > > retrive the inode via proc_pid() in .open() took an additional reference > > via get_pid() and dropped it in .release(). Do we prefer that? > > If you are using proc/<pid>/ directories as your file descriptors, you > don't need to add an open or a release method at all. The existing file > descriptors hold a reference to the inode which holds a reference the > the struct pid. > > The only time you need to get a reference is when you need a task > and kill_pid_info already performs that work for you. Oh, I see what you and Andy are saying now. Sweet, that means we can trim down the patch even more. Less code, less headache. Thanks! > > So using proc_pid is all you need to do to get the pid from the existing > file descriptors. > > Eric >
