#include <linux/bitmap.h>
+#include <linux/bug.h>
#include <linux/export.h>
#include <linux/idr.h>
#include <linux/slab.h>
DEFINE_PER_CPU(struct ida_bitmap *, ida_bitmap);
static DEFINE_SPINLOCK(simple_ida_lock);
-int idr_alloc_cmn(struct idr *idr, void *ptr, unsigned long *index,
- unsigned long start, unsigned long end, gfp_t gfp,
- bool ext)
+/**
+ * idr_alloc_u32() - Allocate an ID.
+ * @idr: IDR handle.
+ * @ptr: Pointer to be associated with the new ID.
+ * @nextid: Pointer to an ID.
+ * @max: The maximum ID to allocate (inclusive).
+ * @gfp: Memory allocation flags.
+ *
+ * Allocates an unused ID in the range specified by @nextid and @max.
+ * Note that @max is inclusive whereas the @end parameter to idr_alloc()
+ * is exclusive. The new ID is assigned to @nextid before the pointer
+ * is inserted into the IDR, so if @nextid points into the object pointed
+ * to by @ptr, a concurrent lookup will not find an uninitialised ID.
+ *
+ * The caller should provide their own locking to ensure that two
+ * concurrent modifications to the IDR are not possible. Read-only
+ * accesses to the IDR may be done under the RCU read lock or may
+ * exclude simultaneous writers.
+ *
+ * Return: 0 if an ID was allocated, -ENOMEM if memory allocation failed,
+ * or -ENOSPC if no free IDs could be found. If an error occurred,
+ * @nextid is unchanged.
+ */
+int idr_alloc_u32(struct idr *idr, void *ptr, u32 *nextid,
+ unsigned long max, gfp_t gfp)
{
struct radix_tree_iter iter;
void __rcu **slot;
+ int base = idr->idr_base;
+ int id = *nextid;
if (WARN_ON_ONCE(radix_tree_is_internal_node(ptr)))
return -EINVAL;
+ if (WARN_ON_ONCE(!(idr->idr_rt.gfp_mask & ROOT_IS_IDR)))
+ idr->idr_rt.gfp_mask |= IDR_RT_MARKER;
- radix_tree_iter_init(&iter, start);
- if (ext)
- slot = idr_get_free_ext(&idr->idr_rt, &iter, gfp, end);
- else
- slot = idr_get_free(&idr->idr_rt, &iter, gfp, end);
+ id = (id < base) ? 0 : id - base;
+ radix_tree_iter_init(&iter, id);
+ slot = idr_get_free(&idr->idr_rt, &iter, gfp, max - base);
if (IS_ERR(slot))
return PTR_ERR(slot);
+ *nextid = iter.index + base;
+ /* there is a memory barrier inside radix_tree_iter_replace() */
radix_tree_iter_replace(&idr->idr_rt, &iter, slot, ptr);
radix_tree_iter_tag_clear(&idr->idr_rt, &iter, IDR_FREE);
- if (index)
- *index = iter.index;
return 0;
}
-EXPORT_SYMBOL_GPL(idr_alloc_cmn);
+EXPORT_SYMBOL_GPL(idr_alloc_u32);
/**
- * idr_alloc_cyclic - allocate new idr entry in a cyclical fashion
- * @idr: idr handle
- * @ptr: pointer to be associated with the new id
- * @start: the minimum id (inclusive)
- * @end: the maximum id (exclusive)
- * @gfp: memory allocation flags
- *
- * Allocates an ID larger than the last ID allocated if one is available.
- * If not, it will attempt to allocate the smallest ID that is larger or
- * equal to @start.
+ * idr_alloc() - Allocate an ID.
+ * @idr: IDR handle.
+ * @ptr: Pointer to be associated with the new ID.
+ * @start: The minimum ID (inclusive).
+ * @end: The maximum ID (exclusive).
+ * @gfp: Memory allocation flags.
+ *
+ * Allocates an unused ID in the range specified by @start and @end. If
+ * @end is <= 0, it is treated as one larger than %INT_MAX. This allows
+ * callers to use @start + N as @end as long as N is within integer range.
+ *
+ * The caller should provide their own locking to ensure that two
+ * concurrent modifications to the IDR are not possible. Read-only
+ * accesses to the IDR may be done under the RCU read lock or may
+ * exclude simultaneous writers.
+ *
+ * Return: The newly allocated ID, -ENOMEM if memory allocation failed,
+ * or -ENOSPC if no free IDs could be found.
*/
-int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp)
+int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp)
{
- int id, curr = idr->idr_next;
+ u32 id = start;
+ int ret;
+
+ if (WARN_ON_ONCE(start < 0))
+ return -EINVAL;
+
+ ret = idr_alloc_u32(idr, ptr, &id, end > 0 ? end - 1 : INT_MAX, gfp);
+ if (ret)
+ return ret;
+
+ return id;
+}
+EXPORT_SYMBOL_GPL(idr_alloc);
- if (curr < start)
- curr = start;
+/**
+ * idr_alloc_cyclic() - Allocate an ID cyclically.
+ * @idr: IDR handle.
+ * @ptr: Pointer to be associated with the new ID.
+ * @start: The minimum ID (inclusive).
+ * @end: The maximum ID (exclusive).
+ * @gfp: Memory allocation flags.
+ *
+ * Allocates an unused ID in the range specified by @nextid and @end. If
+ * @end is <= 0, it is treated as one larger than %INT_MAX. This allows
+ * callers to use @start + N as @end as long as N is within integer range.
+ * The search for an unused ID will start at the last ID allocated and will
+ * wrap around to @start if no free IDs are found before reaching @end.
+ *
+ * The caller should provide their own locking to ensure that two
+ * concurrent modifications to the IDR are not possible. Read-only
+ * accesses to the IDR may be done under the RCU read lock or may
+ * exclude simultaneous writers.
+ *
+ * Return: The newly allocated ID, -ENOMEM if memory allocation failed,
+ * or -ENOSPC if no free IDs could be found.
+ */
+int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp)
+{
+ u32 id = idr->idr_next;
+ int err, max = end > 0 ? end - 1 : INT_MAX;
- id = idr_alloc(idr, ptr, curr, end, gfp);
- if ((id == -ENOSPC) && (curr > start))
- id = idr_alloc(idr, ptr, start, curr, gfp);
+ if ((int)id < start)
+ id = start;
- if (id >= 0)
- idr->idr_next = id + 1U;
+ err = idr_alloc_u32(idr, ptr, &id, max, gfp);
+ if ((err == -ENOSPC) && (id > start)) {
+ id = start;
+ err = idr_alloc_u32(idr, ptr, &id, max, gfp);
+ }
+ if (err)
+ return err;
+ idr->idr_next = id + 1;
return id;
}
EXPORT_SYMBOL(idr_alloc_cyclic);
/**
- * idr_for_each - iterate through all stored pointers
- * @idr: idr handle
- * @fn: function to be called for each pointer
- * @data: data passed to callback function
+ * idr_remove() - Remove an ID from the IDR.
+ * @idr: IDR handle.
+ * @id: Pointer ID.
+ *
+ * Removes this ID from the IDR. If the ID was not previously in the IDR,
+ * this function returns %NULL.
+ *
+ * Since this function modifies the IDR, the caller should provide their
+ * own locking to ensure that concurrent modification of the same IDR is
+ * not possible.
+ *
+ * Return: The pointer formerly associated with this ID.
+ */
+void *idr_remove(struct idr *idr, unsigned long id)
+{
+ return radix_tree_delete_item(&idr->idr_rt, id - idr->idr_base, NULL);
+}
+EXPORT_SYMBOL_GPL(idr_remove);
+
+/**
+ * idr_find() - Return pointer for given ID.
+ * @idr: IDR handle.
+ * @id: Pointer ID.
+ *
+ * Looks up the pointer associated with this ID. A %NULL pointer may
+ * indicate that @id is not allocated or that the %NULL pointer was
+ * associated with this ID.
+ *
+ * This function can be called under rcu_read_lock(), given that the leaf
+ * pointers lifetimes are correctly managed.
+ *
+ * Return: The pointer associated with this ID.
+ */
+void *idr_find(const struct idr *idr, unsigned long id)
+{
+ return radix_tree_lookup(&idr->idr_rt, id - idr->idr_base);
+}
+EXPORT_SYMBOL_GPL(idr_find);
+
+/**
+ * idr_for_each() - Iterate through all stored pointers.
+ * @idr: IDR handle.
+ * @fn: Function to be called for each pointer.
+ * @data: Data passed to callback function.
*
* The callback function will be called for each entry in @idr, passing
- * the id, the pointer and the data pointer passed to this function.
+ * the ID, the entry and @data.
*
* If @fn returns anything other than %0, the iteration stops and that
* value is returned from this function.
{
struct radix_tree_iter iter;
void __rcu **slot;
+ int base = idr->idr_base;
radix_tree_for_each_slot(slot, &idr->idr_rt, &iter, 0) {
- int ret = fn(iter.index, rcu_dereference_raw(*slot), data);
+ int ret;
+
+ if (WARN_ON_ONCE(iter.index > INT_MAX))
+ break;
+ ret = fn(iter.index + base, rcu_dereference_raw(*slot), data);
if (ret)
return ret;
}
EXPORT_SYMBOL(idr_for_each);
/**
- * idr_get_next - Find next populated entry
- * @idr: idr handle
- * @nextid: Pointer to lowest possible ID to return
+ * idr_get_next() - Find next populated entry.
+ * @idr: IDR handle.
+ * @nextid: Pointer to an ID.
*
* Returns the next populated entry in the tree with an ID greater than
* or equal to the value pointed to by @nextid. On exit, @nextid is updated
{
struct radix_tree_iter iter;
void __rcu **slot;
+ int base = idr->idr_base;
+ int id = *nextid;
- slot = radix_tree_iter_find(&idr->idr_rt, &iter, *nextid);
+ id = (id < base) ? 0 : id - base;
+ slot = radix_tree_iter_find(&idr->idr_rt, &iter, id);
if (!slot)
return NULL;
+ id = iter.index + base;
+
+ if (WARN_ON_ONCE(id > INT_MAX))
+ return NULL;
- *nextid = iter.index;
+ *nextid = id;
return rcu_dereference_raw(*slot);
}
EXPORT_SYMBOL(idr_get_next);
-void *idr_get_next_ext(struct idr *idr, unsigned long *nextid)
+/**
+ * idr_get_next_ul() - Find next populated entry.
+ * @idr: IDR handle.
+ * @nextid: Pointer to an ID.
+ *
+ * Returns the next populated entry in the tree with an ID greater than
+ * or equal to the value pointed to by @nextid. On exit, @nextid is updated
+ * to the ID of the found value. To use in a loop, the value pointed to by
+ * nextid must be incremented by the user.
+ */
+void *idr_get_next_ul(struct idr *idr, unsigned long *nextid)
{
struct radix_tree_iter iter;
void __rcu **slot;
+ unsigned long base = idr->idr_base;
+ unsigned long id = *nextid;
- slot = radix_tree_iter_find(&idr->idr_rt, &iter, *nextid);
+ id = (id < base) ? 0 : id - base;
+ slot = radix_tree_iter_find(&idr->idr_rt, &iter, id);
if (!slot)
return NULL;
- *nextid = iter.index;
+ *nextid = iter.index + base;
return rcu_dereference_raw(*slot);
}
-EXPORT_SYMBOL(idr_get_next_ext);
+EXPORT_SYMBOL(idr_get_next_ul);
/**
- * idr_replace - replace pointer for given id
- * @idr: idr handle
- * @ptr: New pointer to associate with the ID
- * @id: Lookup key
+ * idr_replace() - replace pointer for given ID.
+ * @idr: IDR handle.
+ * @ptr: New pointer to associate with the ID.
+ * @id: ID to change.
*
* Replace the pointer registered with an ID and return the old value.
* This function can be called under the RCU read lock concurrently with
* the one being replaced!).
*
* Returns: the old value on success. %-ENOENT indicates that @id was not
- * found. %-EINVAL indicates that @id or @ptr were not valid.
+ * found. %-EINVAL indicates that @ptr was not valid.
*/
-void *idr_replace(struct idr *idr, void *ptr, int id)
-{
- if (id < 0)
- return ERR_PTR(-EINVAL);
-
- return idr_replace_ext(idr, ptr, id);
-}
-EXPORT_SYMBOL(idr_replace);
-
-void *idr_replace_ext(struct idr *idr, void *ptr, unsigned long id)
+void *idr_replace(struct idr *idr, void *ptr, unsigned long id)
{
struct radix_tree_node *node;
void __rcu **slot = NULL;
if (WARN_ON_ONCE(radix_tree_is_internal_node(ptr)))
return ERR_PTR(-EINVAL);
+ id -= idr->idr_base;
entry = __radix_tree_lookup(&idr->idr_rt, id, &node, &slot);
if (!slot || radix_tree_tag_get(&idr->idr_rt, id, IDR_FREE))
return entry;
}
-EXPORT_SYMBOL(idr_replace_ext);
+EXPORT_SYMBOL(idr_replace);
/**
* DOC: IDA description
* bitmap, which is excessive.
*/
-#define IDA_MAX (0x80000000U / IDA_BITMAP_BITS)
+#define IDA_MAX (0x80000000U / IDA_BITMAP_BITS - 1)
/**
* ida_get_new_above - allocate new ID above or equal to a start id
projects / linux.git / blobdiff