| Message ID | 20190129110638.12652-4-paolo.valente@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | batch of patches for next linux release | expand |
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 9ea2c4f42501..b0e8006475be 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -907,8 +907,10 @@ static void bfq_updated_next_req(struct bfq_data *bfqd, */ return; - new_budget = max_t(unsigned long, bfqq->max_budget, - bfq_serv_to_charge(next_rq, bfqq)); + new_budget = max_t(unsigned long, + max_t(unsigned long, bfqq->max_budget, + bfq_serv_to_charge(next_rq, bfqq)), + entity->service); if (entity->budget != new_budget) { entity->budget = new_budget; bfq_log_bfqq(bfqd, bfqq, "updated next rq: new budget %lu",
With some unlucky sequences of events, the function bfq_updated_next_req updates the current budget of a bfq_queue to a lower value than the service received by the queue using such a budget. Unfortunately, if this happens, then the return value of the function bfq_bfqq_budget_left becomes inconsistent. This commit solves this problem by lower-bounding the budget computed in bfq_updated_next_req to the service currently charged to the queue. Signed-off-by: Paolo Valente <paolo.valente@linaro.org> --- block/bfq-iosched.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)