ida: Add new API

[linux-2.6-block.git] / lib / idr.c

diff --git a/lib/idr.c b/lib/idr.c
index 352c6160e2e0c3c0c68955c835ff5549e5bfa57f..760fce92f1fbedd33258a789a180548b0a39bc8a 100644 (file)
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -317,7 +317,8 @@ EXPORT_SYMBOL(idr_replace);
  * bit per ID, and so is more space efficient than an IDR.  To use an IDA,
  * define it using DEFINE_IDA() (or embed a &struct ida in a data structure,
  * then initialise it using ida_init()).  To allocate a new ID, call
- * ida_simple_get().  To free an ID, call ida_simple_remove().
+ * ida_alloc(), ida_alloc_min(), ida_alloc_max() or ida_alloc_range().
+ * To free an ID, call ida_free().
  *
  * If you have more complex locking requirements, use a loop around
  * ida_pre_get() and ida_get_new() to allocate a new ID.  Then use
@@ -378,7 +379,7 @@ EXPORT_SYMBOL(idr_replace);
  * Allocate new ID above or equal to @start.  It should be called
  * with any required locks to ensure that concurrent calls to
  * ida_get_new_above() / ida_get_new() / ida_remove() are not allowed.
- * Consider using ida_simple_get() if you do not have complex locking
+ * Consider using ida_alloc_range() if you do not have complex locking
  * requirements.
  *
  * If memory is required, it will return %-EAGAIN, you should unlock
@@ -551,43 +552,34 @@ void ida_destroy(struct ida *ida)
 EXPORT_SYMBOL(ida_destroy);
 
 /**
- * ida_simple_get - get a new id.
- * @ida: the (initialized) ida.
- * @start: the minimum id (inclusive, < 0x8000000)
- * @end: the maximum id (exclusive, < 0x8000000 or 0)
- * @gfp_mask: memory allocation flags
- *
- * Allocates an id in the range start <= id < end, or returns -ENOSPC.
- * On memory allocation failure, returns -ENOMEM.
+ * ida_alloc_range() - Allocate an unused ID.
+ * @ida: IDA handle.
+ * @min: Lowest ID to allocate.
+ * @max: Highest ID to allocate.
+ * @gfp: Memory allocation flags.
  *
- * Compared to ida_get_new_above() this function does its own locking, and
- * should be used unless there are special requirements.
+ * Allocate an ID between @min and @max, inclusive.  The allocated ID will
+ * not exceed %INT_MAX, even if @max is larger.
  *
- * Use ida_simple_remove() to get rid of an id.
+ * Context: Any context.
+ * Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
+ * or %-ENOSPC if there are no free IDs.
  */
-int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,
-                  gfp_t gfp_mask)
+int ida_alloc_range(struct ida *ida, unsigned int min, unsigned int max,
+                       gfp_t gfp)
 {
        int ret, id;
-       unsigned int max;
        unsigned long flags;
 
-       BUG_ON((int)start < 0);
-       BUG_ON((int)end < 0);
+       if ((int)min < 0)
+               return -ENOSPC;
 
-       if (end == 0)
-               max = 0x80000000;
-       else {
-               BUG_ON(end < start);
-               max = end - 1;
-       }
+       if ((int)max < 0)
+               max = INT_MAX;
 
 again:
-       if (!ida_pre_get(ida, gfp_mask))
-               return -ENOMEM;
-
        xa_lock_irqsave(&ida->ida_rt, flags);
-       ret = ida_get_new_above(ida, start, &id);
+       ret = ida_get_new_above(ida, min, &id);
        if (!ret) {
                if (id > max) {
                        ida_remove(ida, id);
@@ -598,24 +590,24 @@ again:
        }
        xa_unlock_irqrestore(&ida->ida_rt, flags);
 
-       if (unlikely(ret == -EAGAIN))
+       if (unlikely(ret == -EAGAIN)) {
+               if (!ida_pre_get(ida, gfp))
+                       return -ENOMEM;
                goto again;
+       }
 
        return ret;
 }
-EXPORT_SYMBOL(ida_simple_get);
+EXPORT_SYMBOL(ida_alloc_range);
 
 /**
- * ida_simple_remove - remove an allocated id.
- * @ida: the (initialized) ida.
- * @id: the id returned by ida_simple_get.
- *
- * Use to release an id allocated with ida_simple_get().
+ * ida_free() - Release an allocated ID.
+ * @ida: IDA handle.
+ * @id: Previously allocated ID.
  *
- * Compared to ida_remove() this function does its own locking, and should be
- * used unless there are special requirements.
+ * Context: Any context.
  */
-void ida_simple_remove(struct ida *ida, unsigned int id)
+void ida_free(struct ida *ida, unsigned int id)
 {
        unsigned long flags;
 
@@ -624,4 +616,4 @@ void ida_simple_remove(struct ida *ida, unsigned int id)
        ida_remove(ida, id);
        xa_unlock_irqrestore(&ida->ida_rt, flags);
 }
-EXPORT_SYMBOL(ida_simple_remove);
+EXPORT_SYMBOL(ida_free);