diff options
| -rw-r--r-- | net/core/netprio_cgroup.c | 56 |
1 files changed, 33 insertions, 23 deletions
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c index 92cc54c..569d83d 100644 --- a/net/core/netprio_cgroup.c +++ b/net/core/netprio_cgroup.c @@ -27,11 +27,11 @@ #include <linux/fdtable.h> +#define PRIOMAP_MIN_SZ 128 #define PRIOIDX_SZ 128 static unsigned long prioidx_map[PRIOIDX_SZ]; static DEFINE_SPINLOCK(prioidx_map_lock); -static atomic_t max_prioidx = ATOMIC_INIT(0); static inline struct cgroup_netprio_state *cgrp_netprio_state(struct cgroup *cgrp) { @@ -51,8 +51,6 @@ static int get_prioidx(u32 *prio) return -ENOSPC; } set_bit(prioidx, prioidx_map); - if (atomic_read(&max_prioidx) < prioidx) - atomic_set(&max_prioidx, prioidx); spin_unlock_irqrestore(&prioidx_map_lock, flags); *prio = prioidx; return 0; @@ -67,15 +65,40 @@ static void put_prioidx(u32 idx) spin_unlock_irqrestore(&prioidx_map_lock, flags); } -static int extend_netdev_table(struct net_device *dev, u32 new_len) +/* + * Extend @dev->priomap so that it's large enough to accomodate + * @target_idx. @dev->priomap.priomap_len > @target_idx after successful + * return. Must be called under rtnl lock. + */ +static int extend_netdev_table(struct net_device *dev, u32 target_idx) { - size_t new_size = sizeof(struct netprio_map) + - ((sizeof(u32) * new_len)); - struct netprio_map *new = kzalloc(new_size, GFP_KERNEL); - struct netprio_map *old; + struct netprio_map *old, *new; + size_t new_sz, new_len; + /* is the existing priomap large enough? */ old = rtnl_dereference(dev->priomap); + if (old && old->priomap_len > target_idx) + return 0; + + /* + * Determine the new size. Let's keep it power-of-two. We start + * from PRIOMAP_MIN_SZ and double it until it's large enough to + * accommodate @target_idx. + */ + new_sz = PRIOMAP_MIN_SZ; + while (true) { + new_len = (new_sz - offsetof(struct netprio_map, priomap)) / + sizeof(new->priomap[0]); + if (new_len > target_idx) + break; + new_sz *= 2; + /* overflowed? */ + if (WARN_ON(new_sz < PRIOMAP_MIN_SZ)) + return -ENOSPC; + } + /* allocate & copy */ + new = kzalloc(new_sz, GFP_KERNEL); if (!new) { pr_warn("Unable to alloc new priomap!\n"); return -ENOMEM; @@ -87,26 +110,13 @@ static int extend_netdev_table(struct net_device *dev, u32 new_len) new->priomap_len = new_len; + /* install the new priomap */ rcu_assign_pointer(dev->priomap, new); if (old) kfree_rcu(old, rcu); return 0; } -static int write_update_netdev_table(struct net_device *dev) -{ - int ret = 0; - u32 max_len; - struct netprio_map *map; - - max_len = atomic_read(&max_prioidx) + 1; - map = rtnl_dereference(dev->priomap); - if (!map || map->priomap_len < max_len) - ret = extend_netdev_table(dev, max_len); - - return ret; -} - static struct cgroup_subsys_state *cgrp_css_alloc(struct cgroup *cgrp) { struct cgroup_netprio_state *cs; @@ -191,7 +201,7 @@ static int write_priomap(struct cgroup *cgrp, struct cftype *cft, rtnl_lock(); - ret = write_update_netdev_table(dev); + ret = extend_netdev_table(dev, prioidx); if (ret) goto out_unlock; |