diff options
| -rw-r--r-- | include/linux/idr.h | 3 | ||||
| -rw-r--r-- | lib/idr.c | 14 |
2 files changed, 14 insertions, 3 deletions
diff --git a/include/linux/idr.h b/include/linux/idr.h index fa035f96f2a3..dd846df8cd32 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -52,13 +52,14 @@ struct idr_layer { unsigned long bitmap; /* A zero bit means "space here" */ struct idr_layer *ary[1<<IDR_BITS]; int count; /* When zero, we can release it */ + int layer; /* distance from leaf */ struct rcu_head rcu_head; }; struct idr { struct idr_layer *top; struct idr_layer *id_free; - int layers; + int layers; /* only valid without concurrent changes */ int id_free_cnt; spinlock_t lock; }; diff --git a/lib/idr.c b/lib/idr.c index e728c7fccc4d..7a785a0c2ea0 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -185,6 +185,7 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) new = get_from_free_list(idp); if (!new) return -1; + new->layer = l-1; rcu_assign_pointer(p->ary[m], new); p->count++; } @@ -210,6 +211,7 @@ build_up: if (unlikely(!p)) { if (!(p = get_from_free_list(idp))) return -1; + p->layer = 0; layers = 1; } /* @@ -237,6 +239,7 @@ build_up: } new->ary[0] = p; new->count = 1; + new->layer = layers-1; if (p->bitmap == IDR_FULL) __set_bit(0, &new->bitmap); p = new; @@ -493,17 +496,21 @@ void *idr_find(struct idr *idp, int id) int n; struct idr_layer *p; - n = idp->layers * IDR_BITS; p = rcu_dereference(idp->top); + if (!p) + return NULL; + n = (p->layer+1) * IDR_BITS; /* Mask off upper bits we don't use for the search. */ id &= MAX_ID_MASK; if (id >= (1 << n)) return NULL; + BUG_ON(n == 0); while (n > 0 && p) { n -= IDR_BITS; + BUG_ON(n != p->layer*IDR_BITS); p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]); } return((void *)p); @@ -582,8 +589,11 @@ void *idr_replace(struct idr *idp, void *ptr, int id) int n; struct idr_layer *p, *old_p; - n = idp->layers * IDR_BITS; p = idp->top; + if (!p) + return ERR_PTR(-EINVAL); + + n = (p->layer+1) * IDR_BITS; id &= MAX_ID_MASK; |