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-rw-r--r--include/linux/idr.h3
-rw-r--r--lib/idr.c14
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 {
52 unsigned long bitmap; /* A zero bit means "space here" */ 52 unsigned long bitmap; /* A zero bit means "space here" */
53 struct idr_layer *ary[1<<IDR_BITS]; 53 struct idr_layer *ary[1<<IDR_BITS];
54 int count; /* When zero, we can release it */ 54 int count; /* When zero, we can release it */
55 int layer; /* distance from leaf */
55 struct rcu_head rcu_head; 56 struct rcu_head rcu_head;
56}; 57};
57 58
58struct idr { 59struct idr {
59 struct idr_layer *top; 60 struct idr_layer *top;
60 struct idr_layer *id_free; 61 struct idr_layer *id_free;
61 int layers; 62 int layers; /* only valid without concurrent changes */
62 int id_free_cnt; 63 int id_free_cnt;
63 spinlock_t lock; 64 spinlock_t lock;
64}; 65};
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)
185 new = get_from_free_list(idp); 185 new = get_from_free_list(idp);
186 if (!new) 186 if (!new)
187 return -1; 187 return -1;
188 new->layer = l-1;
188 rcu_assign_pointer(p->ary[m], new); 189 rcu_assign_pointer(p->ary[m], new);
189 p->count++; 190 p->count++;
190 } 191 }
@@ -210,6 +211,7 @@ build_up:
210 if (unlikely(!p)) { 211 if (unlikely(!p)) {
211 if (!(p = get_from_free_list(idp))) 212 if (!(p = get_from_free_list(idp)))
212 return -1; 213 return -1;
214 p->layer = 0;
213 layers = 1; 215 layers = 1;
214 } 216 }
215 /* 217 /*
@@ -237,6 +239,7 @@ build_up:
237 } 239 }
238 new->ary[0] = p; 240 new->ary[0] = p;
239 new->count = 1; 241 new->count = 1;
242 new->layer = layers-1;
240 if (p->bitmap == IDR_FULL) 243 if (p->bitmap == IDR_FULL)
241 __set_bit(0, &new->bitmap); 244 __set_bit(0, &new->bitmap);
242 p = new; 245 p = new;
@@ -493,17 +496,21 @@ void *idr_find(struct idr *idp, int id)
493 int n; 496 int n;
494 struct idr_layer *p; 497 struct idr_layer *p;
495 498
496 n = idp->layers * IDR_BITS;
497 p = rcu_dereference(idp->top); 499 p = rcu_dereference(idp->top);
500 if (!p)
501 return NULL;
502 n = (p->layer+1) * IDR_BITS;
498 503
499 /* Mask off upper bits we don't use for the search. */ 504 /* Mask off upper bits we don't use for the search. */
500 id &= MAX_ID_MASK; 505 id &= MAX_ID_MASK;
501 506
502 if (id >= (1 << n)) 507 if (id >= (1 << n))
503 return NULL; 508 return NULL;
509 BUG_ON(n == 0);
504 510
505 while (n > 0 && p) { 511 while (n > 0 && p) {
506 n -= IDR_BITS; 512 n -= IDR_BITS;
513 BUG_ON(n != p->layer*IDR_BITS);
507 p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]); 514 p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]);
508 } 515 }
509 return((void *)p); 516 return((void *)p);
@@ -582,8 +589,11 @@ void *idr_replace(struct idr *idp, void *ptr, int id)
582 int n; 589 int n;
583 struct idr_layer *p, *old_p; 590 struct idr_layer *p, *old_p;
584 591
585 n = idp->layers * IDR_BITS;
586 p = idp->top; 592 p = idp->top;
593 if (!p)
594 return ERR_PTR(-EINVAL);
595
596 n = (p->layer+1) * IDR_BITS;
587 597
588 id &= MAX_ID_MASK; 598 id &= MAX_ID_MASK;
589 599