diff options
Diffstat (limited to 'kernel/bpf/bpf_local_storage.c')
| -rw-r--r-- | kernel/bpf/bpf_local_storage.c | 143 |
1 files changed, 96 insertions, 47 deletions
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index b305270b7a4b..802fc15b0d73 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -11,6 +11,9 @@ #include <net/sock.h> #include <uapi/linux/sock_diag.h> #include <uapi/linux/btf.h> +#include <linux/rcupdate.h> +#include <linux/rcupdate_trace.h> +#include <linux/rcupdate_wait.h> #define BPF_LOCAL_STORAGE_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_CLONE) @@ -60,7 +63,7 @@ static bool selem_linked_to_map(const struct bpf_local_storage_elem *selem) struct bpf_local_storage_elem * bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, - void *value, bool charge_mem) + void *value, bool charge_mem, gfp_t gfp_flags) { struct bpf_local_storage_elem *selem; @@ -68,7 +71,7 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, return NULL; selem = bpf_map_kzalloc(&smap->map, smap->elem_size, - GFP_ATOMIC | __GFP_NOWARN); + gfp_flags | __GFP_NOWARN); if (selem) { if (value) memcpy(SDATA(selem)->data, value, smap->map.value_size); @@ -81,19 +84,35 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, return NULL; } +void bpf_local_storage_free_rcu(struct rcu_head *rcu) +{ + struct bpf_local_storage *local_storage; + + local_storage = container_of(rcu, struct bpf_local_storage, rcu); + kfree_rcu(local_storage, rcu); +} + +static void bpf_selem_free_rcu(struct rcu_head *rcu) +{ + struct bpf_local_storage_elem *selem; + + selem = container_of(rcu, struct bpf_local_storage_elem, rcu); + kfree_rcu(selem, rcu); +} + /* local_storage->lock must be held and selem->local_storage == local_storage. * The caller must ensure selem->smap is still valid to be * dereferenced for its smap->elem_size and smap->cache_idx. */ bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage, struct bpf_local_storage_elem *selem, - bool uncharge_mem) + bool uncharge_mem, bool use_trace_rcu) { struct bpf_local_storage_map *smap; bool free_local_storage; void *owner; - smap = rcu_dereference(SDATA(selem)->smap); + smap = rcu_dereference_check(SDATA(selem)->smap, bpf_rcu_lock_held()); owner = local_storage->owner; /* All uncharging on the owner must be done first. @@ -117,13 +136,13 @@ bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage, * will be done by the caller. * * Although the unlock will be done under - * rcu_read_lock(), it is more intutivie to - * read if kfree_rcu(local_storage, rcu) is done + * rcu_read_lock(), it is more intuitive to + * read if the freeing of the storage is done * after the raw_spin_unlock_bh(&local_storage->lock). * * Hence, a "bool free_local_storage" is returned - * to the caller which then calls the kfree_rcu() - * after unlock. + * to the caller which then calls then frees the storage after + * all the RCU grace periods have expired. */ } hlist_del_init_rcu(&selem->snode); @@ -131,12 +150,16 @@ bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_storage, SDATA(selem)) RCU_INIT_POINTER(local_storage->cache[smap->cache_idx], NULL); - kfree_rcu(selem, rcu); + if (use_trace_rcu) + call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_rcu); + else + kfree_rcu(selem, rcu); return free_local_storage; } -static void __bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem) +static void __bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem, + bool use_trace_rcu) { struct bpf_local_storage *local_storage; bool free_local_storage = false; @@ -146,15 +169,21 @@ static void __bpf_selem_unlink_storage(struct bpf_local_storage_elem *selem) /* selem has already been unlinked from sk */ return; - local_storage = rcu_dereference(selem->local_storage); + local_storage = rcu_dereference_check(selem->local_storage, + bpf_rcu_lock_held()); raw_spin_lock_irqsave(&local_storage->lock, flags); if (likely(selem_linked_to_storage(selem))) free_local_storage = bpf_selem_unlink_storage_nolock( - local_storage, selem, true); + local_storage, selem, true, use_trace_rcu); raw_spin_unlock_irqrestore(&local_storage->lock, flags); - if (free_local_storage) - kfree_rcu(local_storage, rcu); + if (free_local_storage) { + if (use_trace_rcu) + call_rcu_tasks_trace(&local_storage->rcu, + bpf_local_storage_free_rcu); + else + kfree_rcu(local_storage, rcu); + } } void bpf_selem_link_storage_nolock(struct bpf_local_storage *local_storage, @@ -174,7 +203,7 @@ void bpf_selem_unlink_map(struct bpf_local_storage_elem *selem) /* selem has already be unlinked from smap */ return; - smap = rcu_dereference(SDATA(selem)->smap); + smap = rcu_dereference_check(SDATA(selem)->smap, bpf_rcu_lock_held()); b = select_bucket(smap, selem); raw_spin_lock_irqsave(&b->lock, flags); if (likely(selem_linked_to_map(selem))) @@ -194,14 +223,14 @@ void bpf_selem_link_map(struct bpf_local_storage_map *smap, raw_spin_unlock_irqrestore(&b->lock, flags); } -void bpf_selem_unlink(struct bpf_local_storage_elem *selem) +void bpf_selem_unlink(struct bpf_local_storage_elem *selem, bool use_trace_rcu) { /* Always unlink from map before unlinking from local_storage * because selem will be freed after successfully unlinked from * the local_storage. */ bpf_selem_unlink_map(selem); - __bpf_selem_unlink_storage(selem); + __bpf_selem_unlink_storage(selem, use_trace_rcu); } struct bpf_local_storage_data * @@ -213,12 +242,14 @@ bpf_local_storage_lookup(struct bpf_local_storage *local_storage, struct bpf_local_storage_elem *selem; /* Fast path (cache hit) */ - sdata = rcu_dereference(local_storage->cache[smap->cache_idx]); + sdata = rcu_dereference_check(local_storage->cache[smap->cache_idx], + bpf_rcu_lock_held()); if (sdata && rcu_access_pointer(sdata->smap) == smap) return sdata; /* Slow path (cache miss) */ - hlist_for_each_entry_rcu(selem, &local_storage->list, snode) + hlist_for_each_entry_rcu(selem, &local_storage->list, snode, + rcu_read_lock_trace_held()) if (rcu_access_pointer(SDATA(selem)->smap) == smap) break; @@ -260,7 +291,8 @@ static int check_flags(const struct bpf_local_storage_data *old_sdata, int bpf_local_storage_alloc(void *owner, struct bpf_local_storage_map *smap, - struct bpf_local_storage_elem *first_selem) + struct bpf_local_storage_elem *first_selem, + gfp_t gfp_flags) { struct bpf_local_storage *prev_storage, *storage; struct bpf_local_storage **owner_storage_ptr; @@ -271,7 +303,7 @@ int bpf_local_storage_alloc(void *owner, return err; storage = bpf_map_kzalloc(&smap->map, sizeof(*storage), - GFP_ATOMIC | __GFP_NOWARN); + gfp_flags | __GFP_NOWARN); if (!storage) { err = -ENOMEM; goto uncharge; @@ -306,7 +338,8 @@ int bpf_local_storage_alloc(void *owner, * bucket->list, first_selem can be freed immediately * (instead of kfree_rcu) because * bpf_local_storage_map_free() does a - * synchronize_rcu() before walking the bucket->list. + * synchronize_rcu_mult (waiting for both sleepable and + * normal programs) before walking the bucket->list. * Hence, no one is accessing selem from the * bucket->list under rcu_read_lock(). */ @@ -327,10 +360,10 @@ uncharge: */ struct bpf_local_storage_data * bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, - void *value, u64 map_flags) + void *value, u64 map_flags, gfp_t gfp_flags) { struct bpf_local_storage_data *old_sdata = NULL; - struct bpf_local_storage_elem *selem; + struct bpf_local_storage_elem *selem = NULL; struct bpf_local_storage *local_storage; unsigned long flags; int err; @@ -342,18 +375,22 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, !map_value_has_spin_lock(&smap->map))) return ERR_PTR(-EINVAL); - local_storage = rcu_dereference(*owner_storage(smap, owner)); + if (gfp_flags == GFP_KERNEL && (map_flags & ~BPF_F_LOCK) != BPF_NOEXIST) + return ERR_PTR(-EINVAL); + + local_storage = rcu_dereference_check(*owner_storage(smap, owner), + bpf_rcu_lock_held()); if (!local_storage || hlist_empty(&local_storage->list)) { /* Very first elem for the owner */ err = check_flags(NULL, map_flags); if (err) return ERR_PTR(err); - selem = bpf_selem_alloc(smap, owner, value, true); + selem = bpf_selem_alloc(smap, owner, value, true, gfp_flags); if (!selem) return ERR_PTR(-ENOMEM); - err = bpf_local_storage_alloc(owner, smap, selem); + err = bpf_local_storage_alloc(owner, smap, selem, gfp_flags); if (err) { kfree(selem); mem_uncharge(smap, owner, smap->elem_size); @@ -380,6 +417,12 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, } } + if (gfp_flags == GFP_KERNEL) { + selem = bpf_selem_alloc(smap, owner, value, true, gfp_flags); + if (!selem) + return ERR_PTR(-ENOMEM); + } + raw_spin_lock_irqsave(&local_storage->lock, flags); /* Recheck local_storage->list under local_storage->lock */ @@ -405,19 +448,21 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, goto unlock; } - /* local_storage->lock is held. Hence, we are sure - * we can unlink and uncharge the old_sdata successfully - * later. Hence, instead of charging the new selem now - * and then uncharge the old selem later (which may cause - * a potential but unnecessary charge failure), avoid taking - * a charge at all here (the "!old_sdata" check) and the - * old_sdata will not be uncharged later during - * bpf_selem_unlink_storage_nolock(). - */ - selem = bpf_selem_alloc(smap, owner, value, !old_sdata); - if (!selem) { - err = -ENOMEM; - goto unlock_err; + if (gfp_flags != GFP_KERNEL) { + /* local_storage->lock is held. Hence, we are sure + * we can unlink and uncharge the old_sdata successfully + * later. Hence, instead of charging the new selem now + * and then uncharge the old selem later (which may cause + * a potential but unnecessary charge failure), avoid taking + * a charge at all here (the "!old_sdata" check) and the + * old_sdata will not be uncharged later during + * bpf_selem_unlink_storage_nolock(). + */ + selem = bpf_selem_alloc(smap, owner, value, !old_sdata, gfp_flags); + if (!selem) { + err = -ENOMEM; + goto unlock_err; + } } /* First, link the new selem to the map */ @@ -430,7 +475,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, if (old_sdata) { bpf_selem_unlink_map(SELEM(old_sdata)); bpf_selem_unlink_storage_nolock(local_storage, SELEM(old_sdata), - false); + false, true); } unlock: @@ -439,6 +484,10 @@ unlock: unlock_err: raw_spin_unlock_irqrestore(&local_storage->lock, flags); + if (selem) { + mem_uncharge(smap, owner, smap->elem_size); + kfree(selem); + } return ERR_PTR(err); } @@ -506,11 +555,11 @@ void bpf_local_storage_map_free(struct bpf_local_storage_map *smap, struct bpf_local_storage_elem, map_node))) { if (busy_counter) { migrate_disable(); - __this_cpu_inc(*busy_counter); + this_cpu_inc(*busy_counter); } - bpf_selem_unlink(selem); + bpf_selem_unlink(selem, false); if (busy_counter) { - __this_cpu_dec(*busy_counter); + this_cpu_dec(*busy_counter); migrate_enable(); } cond_resched_rcu(); @@ -533,7 +582,7 @@ void bpf_local_storage_map_free(struct bpf_local_storage_map *smap, synchronize_rcu(); kvfree(smap->buckets); - kfree(smap); + bpf_map_area_free(smap); } int bpf_local_storage_map_alloc_check(union bpf_attr *attr) @@ -561,7 +610,7 @@ struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr) unsigned int i; u32 nbuckets; - smap = kzalloc(sizeof(*smap), GFP_USER | __GFP_NOWARN | __GFP_ACCOUNT); + smap = bpf_map_area_alloc(sizeof(*smap), NUMA_NO_NODE); if (!smap) return ERR_PTR(-ENOMEM); bpf_map_init_from_attr(&smap->map, attr); @@ -574,7 +623,7 @@ struct bpf_local_storage_map *bpf_local_storage_map_alloc(union bpf_attr *attr) smap->buckets = kvcalloc(sizeof(*smap->buckets), nbuckets, GFP_USER | __GFP_NOWARN | __GFP_ACCOUNT); if (!smap->buckets) { - kfree(smap); + bpf_map_area_free(smap); return ERR_PTR(-ENOMEM); } |