lib: add idr_for_each()

[linux-2.6] / lib / idr.c

diff --git a/lib/idr.c b/lib/idr.c
index b98f01a2eb946b221f5d7d7d193422f95e607a3a..d29da6159dae0637f5da6042c369ec609207b7de 100644 (file)
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -436,6 +436,61 @@ void *idr_find(struct idr *idp, int id)
 }
 EXPORT_SYMBOL(idr_find);
 
+/**
+ * idr_for_each - iterate through all stored pointers
+ * @idp: idr handle
+ * @fn: function to be called for each pointer
+ * @data: data passed back to callback function
+ *
+ * Iterate over the pointers registered with the given idr.  The
+ * callback function will be called for each pointer currently
+ * registered, passing the id, the pointer and the data pointer passed
+ * to this function.  It is not safe to modify the idr tree while in
+ * the callback, so functions such as idr_get_new and idr_remove are
+ * not allowed.
+ *
+ * We check the return of @fn each time. If it returns anything other
+ * than 0, we break out and return that value.
+ *
+ * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove().
+ */
+int idr_for_each(struct idr *idp,
+                int (*fn)(int id, void *p, void *data), void *data)
+{
+       int n, id, max, error = 0;
+       struct idr_layer *p;
+       struct idr_layer *pa[MAX_LEVEL];
+       struct idr_layer **paa = &pa[0];
+
+       n = idp->layers * IDR_BITS;
+       p = idp->top;
+       max = 1 << n;
+
+       id = 0;
+       while (id < max) {
+               while (n > 0 && p) {
+                       n -= IDR_BITS;
+                       *paa++ = p;
+                       p = p->ary[(id >> n) & IDR_MASK];
+               }
+
+               if (p) {
+                       error = fn(id, (void *)p, data);
+                       if (error)
+                               break;
+               }
+
+               id += 1 << n;
+               while (n < fls(id)) {
+                       n += IDR_BITS;
+                       p = *--paa;
+               }
+       }
+
+       return error;
+}
+EXPORT_SYMBOL(idr_for_each);
+
 /**
  * idr_replace - replace pointer for given id
  * @idp: idr handle