Hubertus Franke <frankeh@watson.ibm.com> writes:
> On Friday 15 March 2002 10:16 am, OGAWA Hirofumi wrote:
> > Whoops! I'm sorry. previous email was the middle of writing.
> >
> > Hubertus Franke <frankeh@watson.ibm.com> writes:
> > > + if (i == PID_MAP_SIZE) {
> > > + if (again) {
> > > + /* we didn't find any pid , sweep and try again */
> > > + again = 0;
> > > + memset(pid_map, 0, PID_MAP_SIZE * sizeof(unsigned long));
> > > + last_pid = RESERVED_PIDS;
> > > + goto repeat;
> > > + }
> > > + next_safe = RESERVED_PIDS;
> > > + return 0;
> >
> > Probably, the bug is here. No bug ....
>
> >
> > + next_safe = RESERVED_PIDS; /* or 0 */
> >
> > > + read_unlock(&tasklist_lock);
> > > + spin_unlock(&lastpid_lock);
> > > + return 0;
> > > }
> >
> > Basically nice, I think.
> >
> > BTW, How about using the __set_bit(), find_next_zero_bit(), and
> > find_next_bit() in get_pid_by_map().
> >
> > Thanks for nice work.
>
> OGAWA, honestly I only tried testcase 2.
> But looking at your suggestion its not clear to me whether
> there is a bug.
> Remember we need to determine a valid interval [ last_pid .. next_safe ).
> In the pid_map function, if no pid is available, then
> [ PID_MAX .. PID_MAX ) will be returned.
> The other path should also end up with this as well.
> Could you point where you see this not happening.
Maybe my point was unclear. Sorry.
Please consider what happens after using up pid. Then,
get_pid_by_map() returns 0.
And last_pid = 0, next_safe = RESERVED_PIDS. After it, get_pid()
returns the values between 0 and RESERVED_PIDS.
And the line which I added is also the same reason.
Regards.
-- OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sat Mar 23 2002 - 22:00:11 EST