Commit 624b85fb authored Mar 05, 2013 by Paolo Valente Committed by David S. Miller Mar 06, 2013

pkt_sched: sch_qfq: fix the update of eligible-group sets



Between two invocations of make_eligible, the system virtual time may
happen to grow enough that, in its binary representation, a bit with
higher order than 31 flips. This happens especially with
TSO/GSO. Before this fix, the mask used in make_eligible was computed
as (1UL<<index_of_last_flipped_bit)-1, whose value is well defined on
a 64-bit architecture, because index_of_flipped_bit <= 63, but is in
general undefined on a 32-bit architecture if index_of_flipped_bit > 31.
The fix just replaces 1UL with 1ULL.

Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Reviewed-by: Fabio Checconi <fchecconi@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 9b99b7e9

net/sched/sch_qfq.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -821,7 +821,7 @@ static void qfq_make_eligible(struct qfq_sched *q)
		unsigned long old_vslot = q->oldV >> q->min_slot_shift;

		if (vslot != old_vslot) {
		unsigned long mask = (1UL << fls(vslot ^ old_vslot)) - 1;
		unsigned long mask = (1ULL << fls(vslot ^ old_vslot)) - 1;
		qfq_move_groups(q, mask, IR, ER);
		qfq_move_groups(q, mask, IB, EB);
		}

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