diff options
Diffstat (limited to 'block/blk-iocost.c')
| -rw-r--r-- | block/blk-iocost.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 6e29b4dcf356..ef9476fca1d8 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -2323,9 +2323,8 @@ static u64 adjust_inuse_and_calc_cost(struct ioc_gq *iocg, u64 vtime, { struct ioc *ioc = iocg->ioc; struct ioc_margins *margins = &ioc->margins; - u32 adj_step = DIV_ROUND_UP(iocg->active * INUSE_ADJ_STEP_PCT, 100); u32 __maybe_unused old_inuse = iocg->inuse, __maybe_unused old_hwi; - u32 hwi; + u32 hwi, adj_step; s64 margin; u64 cost, new_inuse; @@ -2354,8 +2353,15 @@ static u64 adjust_inuse_and_calc_cost(struct ioc_gq *iocg, u64 vtime, return cost; } - /* bump up inuse till @abs_cost fits in the existing budget */ + /* + * Bump up inuse till @abs_cost fits in the existing budget. + * adj_step must be determined after acquiring ioc->lock - we might + * have raced and lost to another thread for activation and could + * be reading 0 iocg->active before ioc->lock which will lead to + * infinite loop. + */ new_inuse = iocg->inuse; + adj_step = DIV_ROUND_UP(iocg->active * INUSE_ADJ_STEP_PCT, 100); do { new_inuse = new_inuse + adj_step; propagate_weights(iocg, iocg->active, new_inuse, true, now); |