X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fidr.c;h=71853531d3b0f6be6c0db0420ca8d646dd884469;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=595c76bcb8dd705ead8862fbf235b4af215adb6d;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git

diff --git a/lib/idr.c b/lib/idr.c
index 595c76bcb..71853531d 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -29,10 +29,11 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #endif
+#include <linux/err.h>
 #include <linux/string.h>
 #include <linux/idr.h>
 
-static kmem_cache_t *idr_layer_cache;
+static struct kmem_cache *idr_layer_cache;
 
 static struct idr_layer *alloc_layer(struct idr *idp)
 {
@@ -402,7 +403,49 @@ void *idr_find(struct idr *idp, int id)
 }
 EXPORT_SYMBOL(idr_find);
 
-static void idr_cache_ctor(void * idr_layer, kmem_cache_t *idr_layer_cache,
+/**
+ * idr_replace - replace pointer for given id
+ * @idp: idr handle
+ * @ptr: pointer you want associated with the id
+ * @id: lookup key
+ *
+ * Replace the pointer registered with an id and return the old value.
+ * 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().
+ */
+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;
+
+	id &= MAX_ID_MASK;
+
+	if (id >= (1 << n))
+		return ERR_PTR(-EINVAL);
+
+	n -= IDR_BITS;
+	while ((n > 0) && p) {
+		p = p->ary[(id >> n) & IDR_MASK];
+		n -= IDR_BITS;
+	}
+
+	n = id & IDR_MASK;
+	if (unlikely(p == NULL || !test_bit(n, &p->bitmap)))
+		return ERR_PTR(-ENOENT);
+
+	old_p = p->ary[n];
+	p->ary[n] = ptr;
+
+	return old_p;
+}
+EXPORT_SYMBOL(idr_replace);
+
+static void idr_cache_ctor(void * idr_layer, struct kmem_cache *idr_layer_cache,
 		unsigned long flags)
 {
 	memset(idr_layer, 0, sizeof(struct idr_layer));