On Tue, Oct 18, 2022 at 11:51:02AM -0700, Ivan Babrou wrote:
> On Tue, Oct 18, 2022 at 11:16 AM Brian Foster <bfoster@xxxxxxxxxx> wrote:
> > > +static int proc_readfd_count(struct inode *inode)
> > > +{
> > > + struct task_struct *p = get_proc_task(inode);
> > > + struct fdtable *fdt;
> > > + unsigned int open_fds = 0;
> > > +
> > > + if (!p)
> > > + return -ENOENT;
> >
> > Maybe this shouldn't happen, but do you mean to assign the error code to
> > stat->size in the caller? Otherwise this seems reasonable to me.
>
> You are right. As unlikely as it is to happen, we shouldn't return
> negative size.
>
> What's the idiomatic way to make this work? My two options are:
>
> 1. Pass &stat->size into proc_readfd_count:
>
> if (S_ISDIR(inode->i_mode)) {
> rv = proc_readfd_count(inode, &stat->size);
> if (rv < 0)
> goto out;
> }
>
> out:
> return rv;
>
> OR without a goto:
>
> if (S_ISDIR(inode->i_mode)) {
> rv = proc_readfd_count(inode, &stat->size));
> if (rv < 0)
> return rv;
> }
>
> return rv;
>
> 2. Return negative count as error (as we don't expect negative amount
> of files open):
>
> if (S_ISDIR(inode->i_mode)) {
> size = proc_readfd_count(inode);
> if (size < 0)
> return size;
> stat->size = size;
> }
>
I suppose the latter is less of a change to the original patch..? Either
way seems reasonable to me. I have no strong preference FWIW.
Brian
