On Tue, Apr 10, 2018 at 01:05:57PM +0200, Martin Pieuchot wrote:
> Document that we're using the current reference instead of incrementing
> then decrementing the refcount in finishdup().
Could finishdup() kassert that (fp->f_count > 0) ?
> Ok?
OK bluhm@
> Index: kern/kern_descrip.c
> ===================================================================
> RCS file: /cvs/src/sys/kern/kern_descrip.c,v
> retrieving revision 1.147
> diff -u -p -r1.147 kern_descrip.c
> --- kern/kern_descrip.c 9 Apr 2018 13:59:03 -0000 1.147
> +++ kern/kern_descrip.c 10 Apr 2018 11:01:45 -0000
> @@ -241,6 +241,7 @@ restart:
> }
> goto out;
> }
> + /* No need for FRELE(), finishdup() uses current ref. */
> error = finishdup(p, fp, old, new, retval, 0);
>
> out:
> @@ -320,7 +321,7 @@ restart:
> panic("dup2: fdalloc");
> fd_unused(fdp, new);
> }
> - /* finishdup() does FRELE */
> + /* No need for FRELE(), finishdup() uses current ref. */
> error = finishdup(p, fp, old, new, retval, 1);
> if (!error && flags & O_CLOEXEC)
> fdp->fd_ofileflags[new] |= UF_EXCLOSE;
> @@ -376,7 +377,7 @@ restart:
> goto restart;
> }
> } else {
> - /* finishdup will FRELE for us. */
> + /* No need for FRELE(), finishdup() uses current ref. */
> error = finishdup(p, fp, fd, i, retval, 0);
>
> if (!error && SCARG(uap, cmd) == F_DUPFD_CLOEXEC)
> @@ -616,8 +617,6 @@ finishdup(struct proc *p, struct file *f
>
> fdp->fd_ofiles[new] = fp;
> fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] & ~UF_EXCLOSE;
> - fp->f_count++;
> - FRELE(fp, p);
> if (dup2 && oldfp == NULL)
> fd_used(fdp, new);
> *retval = new;
