idr: separate out idr_mark_full()

Separate out idr_mark_full() from sub_alloc() and make marking the
allocated slot full the responsibility of idr_get_new_above_int().

Allocation part of idr_get_new_above_int() is renamed to
idr_get_empty_slot().  New idr_get_new_above_int() allocates a slot
using the function, install the user pointer and marks it full using
idr_mark_full().

This change doesn't introduce any behavior change.  This will be
used by ida.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/lib/idr.c b/lib/idr.c
index 7b5a59c..30b33e2 100644 (file)
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -70,6 +70,26 @@ static void free_layer(struct idr *idp, struct idr_layer *p)
        spin_unlock_irqrestore(&idp->lock, flags);
 }
 
+static void idr_mark_full(struct idr_layer **pa, int id)
+{
+       struct idr_layer *p = pa[0];
+       int l = 0;
+
+       __set_bit(id & IDR_MASK, &p->bitmap);
+       /*
+        * If this layer is full mark the bit in the layer above to
+        * show that this part of the radix tree is full.  This may
+        * complete the layer above and require walking up the radix
+        * tree.
+        */
+       while (p->bitmap == IDR_FULL) {
+               if (!(p = pa[++l]))
+                       break;
+               id = id >> IDR_BITS;
+               __set_bit((id & IDR_MASK), &p->bitmap);
+       }
+}
+
 /**
  * idr_pre_get - reserver resources for idr allocation
  * @idp:       idr handle
@@ -95,11 +115,10 @@ int idr_pre_get(struct idr *idp, gfp_t gfp_mask)
 }
 EXPORT_SYMBOL(idr_pre_get);
 
-static int sub_alloc(struct idr *idp, void *ptr, int *starting_id)
+static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa)
 {
        int n, m, sh;
        struct idr_layer *p, *new;
-       struct idr_layer *pa[MAX_LEVEL];
        int l, id, oid;
        long bm;
 
@@ -156,30 +175,13 @@ static int sub_alloc(struct idr *idp, void *ptr, int *starting_id)
                pa[l--] = p;
                p = p->ary[m];
        }
-       /*
-        * We have reached the leaf node, plant the
-        * users pointer and return the raw id.
-        */
-       p->ary[m] = (struct idr_layer *)ptr;
-       __set_bit(m, &p->bitmap);
-       p->count++;
-       /*
-        * If this layer is full mark the bit in the layer above
-        * to show that this part of the radix tree is full.
-        * This may complete the layer above and require walking
-        * up the radix tree.
-        */
-       n = id;
-       while (p->bitmap == IDR_FULL) {
-               if (!(p = pa[++l]))
-                       break;
-               n = n >> IDR_BITS;
-               __set_bit((n & IDR_MASK), &p->bitmap);
-       }
-       return(id);
+
+       pa[l] = p;
+       return id;
 }
 
-static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id)
+static int idr_get_empty_slot(struct idr *idp, int starting_id,
+                             struct idr_layer **pa)
 {
        struct idr_layer *p, *new;
        int layers, v, id;
@@ -225,12 +227,31 @@ build_up:
        }
        idp->top = p;
        idp->layers = layers;
-       v = sub_alloc(idp, ptr, &id);
+       v = sub_alloc(idp, &id, pa);
        if (v == -2)
                goto build_up;
        return(v);
 }
 
+static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id)
+{
+       struct idr_layer *pa[MAX_LEVEL];
+       int id;
+
+       id = idr_get_empty_slot(idp, starting_id, pa);
+       if (id >= 0) {
+               /*
+                * Successfully found an empty slot.  Install the user
+                * pointer and mark the slot full.
+                */
+               pa[0]->ary[id & IDR_MASK] = (struct idr_layer *)ptr;
+               pa[0]->count++;
+               idr_mark_full(pa, id);
+       }
+
+       return id;
+}
+
 /**
  * idr_get_new_above - allocate new idr entry above or equal to a start id
  * @idp: idr handle