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Subject[PATCH 02/21] idr: separate out idr_mark_full()
Date
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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>
---
lib/idr.c | 71 +++++++++++++++++++++++++++++++++++++++---------------------
1 files changed, 46 insertions(+), 25 deletions(-)
diff --git a/lib/idr.c b/lib/idr.c
index 7b5a59c..30b33e2 100644
--- 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
--
1.5.0.3

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