return(p);
}
+static void idr_layer_rcu_free(struct rcu_head *head)
+{
+ struct idr_layer *layer;
+
+ layer = container_of(head, struct idr_layer, rcu_head);
+ kmem_cache_free(idr_layer_cache, layer);
+}
+
+static inline void free_layer(struct idr_layer *p)
+{
+ call_rcu(&p->rcu_head, idr_layer_rcu_free);
+}
+
/* only called when idp->lock is held */
static void __move_to_free_list(struct idr *idp, struct idr_layer *p)
{
{
while (idp->id_free_cnt < IDR_FREE_MAX) {
struct idr_layer *new;
- new = kmem_cache_alloc(idr_layer_cache, gfp_mask);
+ new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
if (new == NULL)
return (0);
move_to_free_list(idp, new);
new = get_from_free_list(idp);
if (!new)
return -1;
+ new->layer = l-1;
rcu_assign_pointer(p->ary[m], new);
p->count++;
}
if (unlikely(!p)) {
if (!(p = get_from_free_list(idp)))
return -1;
+ p->layer = 0;
layers = 1;
}
/*
*/
while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) {
layers++;
- if (!p->count)
+ if (!p->count) {
+ /* special case: if the tree is currently empty,
+ * then we grow the tree by moving the top node
+ * upwards.
+ */
+ p->layer++;
continue;
+ }
if (!(new = get_from_free_list(idp))) {
/*
* The allocation failed. If we built part of
}
new->ary[0] = p;
new->count = 1;
+ new->layer = layers-1;
if (p->bitmap == IDR_FULL)
__set_bit(0, &new->bitmap);
p = new;
/**
* idr_get_new_above - allocate new idr entry above or equal to a start id
* @idp: idr handle
- * @ptr: pointer you want associated with the ide
+ * @ptr: pointer you want associated with the id
* @start_id: id to start search at
* @id: pointer to the allocated handle
*
* and go back to the idr_pre_get() call. If the idr is full, it will
* return -ENOSPC.
*
- * @id returns a value in the range 0 ... 0x7fffffff
+ * @id returns a value in the range @starting_id ... 0x7fffffff
*/
int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id)
{
/**
* idr_get_new - allocate new idr entry
* @idp: idr handle
- * @ptr: pointer you want associated with the ide
+ * @ptr: pointer you want associated with the id
* @id: pointer to the allocated handle
*
* This is the allocate id function. It should be called with any
struct idr_layer *p = idp->top;
struct idr_layer **pa[MAX_LEVEL];
struct idr_layer ***paa = &pa[0];
+ struct idr_layer *to_free;
int n;
*paa = NULL;
n = id & IDR_MASK;
if (likely(p != NULL && test_bit(n, &p->bitmap))){
__clear_bit(n, &p->bitmap);
- p->ary[n] = NULL;
+ rcu_assign_pointer(p->ary[n], NULL);
+ to_free = NULL;
while(*paa && ! --((**paa)->count)){
- move_to_free_list(idp, **paa);
+ if (to_free)
+ free_layer(to_free);
+ to_free = **paa;
**paa-- = NULL;
}
if (!*paa)
idp->layers = 0;
+ if (to_free)
+ free_layer(to_free);
} else
idr_remove_warning(id);
}
void idr_remove(struct idr *idp, int id)
{
struct idr_layer *p;
+ struct idr_layer *to_free;
/* Mask off upper bits we don't use for the search. */
id &= MAX_ID_MASK;
sub_remove(idp, (idp->layers - 1) * IDR_BITS, id);
if (idp->top && idp->top->count == 1 && (idp->layers > 1) &&
- idp->top->ary[0]) { // We can drop a layer
-
+ idp->top->ary[0]) {
+ /*
+ * Single child at leftmost slot: we can shrink the tree.
+ * This level is not needed anymore since when layers are
+ * inserted, they are inserted at the top of the existing
+ * tree.
+ */
+ to_free = idp->top;
p = idp->top->ary[0];
- idp->top->bitmap = idp->top->count = 0;
- move_to_free_list(idp, idp->top);
- idp->top = p;
+ rcu_assign_pointer(idp->top, p);
--idp->layers;
+ to_free->bitmap = to_free->count = 0;
+ free_layer(to_free);
}
while (idp->id_free_cnt >= IDR_FREE_MAX) {
p = get_from_free_list(idp);
+ /*
+ * Note: we don't call the rcu callback here, since the only
+ * layers that fall into the freelist are those that have been
+ * preallocated.
+ */
kmem_cache_free(idr_layer_cache, p);
}
return;
n = idp->layers * IDR_BITS;
p = idp->top;
+ rcu_assign_pointer(idp->top, NULL);
max = 1 << n;
id = 0;
id += 1 << n;
while (n < fls(id)) {
- if (p) {
- memset(p, 0, sizeof *p);
- move_to_free_list(idp, p);
- }
+ if (p)
+ free_layer(p);
n += IDR_BITS;
p = *--paa;
}
}
- idp->top = NULL;
idp->layers = 0;
}
EXPORT_SYMBOL(idr_remove_all);
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);
EXPORT_SYMBOL(idr_for_each);
/**
+ * idr_get_next - lookup next object of id to given id.
+ * @idp: idr handle
+ * @id: pointer to lookup key
+ *
+ * Returns pointer to registered object with id, which is next number to
+ * given id.
+ */
+
+void *idr_get_next(struct idr *idp, int *nextidp)
+{
+ struct idr_layer *p, *pa[MAX_LEVEL];
+ struct idr_layer **paa = &pa[0];
+ int id = *nextidp;
+ int n, max;
+
+ /* find first ent */
+ n = idp->layers * IDR_BITS;
+ max = 1 << n;
+ p = rcu_dereference(idp->top);
+ if (!p)
+ return NULL;
+
+ while (id < max) {
+ while (n > 0 && p) {
+ n -= IDR_BITS;
+ *paa++ = p;
+ p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]);
+ }
+
+ if (p) {
+ *nextidp = id;
+ return p;
+ }
+
+ id += 1 << n;
+ while (n < fls(id)) {
+ n += IDR_BITS;
+ p = *--paa;
+ }
+ }
+ return NULL;
+}
+
+
+
+/**
* idr_replace - replace pointer for given id
* @idp: idr handle
* @ptr: pointer you want associated with the id
* A -ENOENT return indicates that @id was not found.
* A -EINVAL return indicates that @id was not within valid constraints.
*
- * The caller must serialize vs idr_find(), idr_get_new(), and idr_remove().
+ * The caller must serialize with writers.
*/
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;
return ERR_PTR(-ENOENT);
old_p = p->ary[n];
- p->ary[n] = ptr;
+ rcu_assign_pointer(p->ary[n], ptr);
return old_p;
}
EXPORT_SYMBOL(idr_replace);
-static void idr_cache_ctor(struct kmem_cache *idr_layer_cache, void *idr_layer)
-{
- memset(idr_layer, 0, sizeof(struct idr_layer));
-}
-
void __init idr_init_cache(void)
{
idr_layer_cache = kmem_cache_create("idr_layer_cache",
- sizeof(struct idr_layer), 0, SLAB_PANIC,
- idr_cache_ctor);
+ sizeof(struct idr_layer), 0, SLAB_PANIC, NULL);
}
/**
* and go back to the ida_pre_get() call. If the ida is full, it will
* return -ENOSPC.
*
- * @p_id returns a value in the range 0 ... 0x7fffffff.
+ * @p_id returns a value in the range @starting_id ... 0x7fffffff.
*/
int ida_get_new_above(struct ida *ida, int starting_id, int *p_id)
{
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff