From a38eb630fa224d6fba8c14a4063174bc5e0f63bb Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Tue, 25 Oct 2011 15:48:12 +0200 Subject: blk-throttle: Take blkcg->lock while traversing blkcg->policy_list blkcg->policy_list is protected by blkcg->lock. Its not rcu protected list. So even for readers, they need to take blkcg->lock. There are few functions which were reading the list without taking lock. Fix it. Signed-off-by: Vivek Goyal Acked-by: Tejun Heo Signed-off-by: Jens Axboe --- block/blk-cgroup.c | 54 ++++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 40 insertions(+), 14 deletions(-) (limited to 'block/blk-cgroup.c') diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 61553670735..8f630cec906 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -869,60 +869,86 @@ unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg, dev_t dev) { struct blkio_policy_node *pn; + unsigned long flags; + unsigned int weight; + + spin_lock_irqsave(&blkcg->lock, flags); pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_PROP, BLKIO_PROP_weight_device); if (pn) - return pn->val.weight; + weight = pn->val.weight; else - return blkcg->weight; + weight = blkcg->weight; + + spin_unlock_irqrestore(&blkcg->lock, flags); + + return weight; } EXPORT_SYMBOL_GPL(blkcg_get_weight); uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg, dev_t dev) { struct blkio_policy_node *pn; + unsigned long flags; + uint64_t bps = -1; + spin_lock_irqsave(&blkcg->lock, flags); pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL, BLKIO_THROTL_read_bps_device); if (pn) - return pn->val.bps; - else - return -1; + bps = pn->val.bps; + spin_unlock_irqrestore(&blkcg->lock, flags); + + return bps; } uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg, dev_t dev) { struct blkio_policy_node *pn; + unsigned long flags; + uint64_t bps = -1; + + spin_lock_irqsave(&blkcg->lock, flags); pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL, BLKIO_THROTL_write_bps_device); if (pn) - return pn->val.bps; - else - return -1; + bps = pn->val.bps; + spin_unlock_irqrestore(&blkcg->lock, flags); + + return bps; } unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg, dev_t dev) { struct blkio_policy_node *pn; + unsigned long flags; + unsigned int iops = -1; + spin_lock_irqsave(&blkcg->lock, flags); pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL, BLKIO_THROTL_read_iops_device); if (pn) - return pn->val.iops; - else - return -1; + iops = pn->val.iops; + spin_unlock_irqrestore(&blkcg->lock, flags); + + return iops; } unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg, dev_t dev) { struct blkio_policy_node *pn; + unsigned long flags; + unsigned int iops = -1; + + spin_lock_irqsave(&blkcg->lock, flags); pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL, BLKIO_THROTL_write_iops_device); if (pn) - return pn->val.iops; - else - return -1; + iops = pn->val.iops; + spin_unlock_irqrestore(&blkcg->lock, flags); + + return iops; } /* Checks whether user asked for deleting a policy rule */ -- cgit v1.2.3-70-g09d2