maple_tree: rework mtree_alloc_{range,rrange}()

Patch series "Clean ups for maple tree", v4.

Some clean ups, mainly to make the code of maple tree more concise.
This patchset has passed the self-test.

This patch (of 10):

Use mas_empty_area{_rev}() to refactor mtree_alloc_{range,rrange}()

Link: https://lkml.kernel.org/r/20230524031247.65949-2-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 4eb2200..96d102d 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -6493,31 +6493,33 @@ int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp,
 {
        int ret = 0;
 
-       MA_STATE(mas, mt, min, min);
+       MA_STATE(mas, mt, 0, 0);
        if (!mt_is_alloc(mt))
                return -EINVAL;
 
        if (WARN_ON_ONCE(mt_is_reserved(entry)))
                return -EINVAL;
 
-       if (min > max)
-               return -EINVAL;
-
-       if (max < size)
-               return -EINVAL;
-
-       if (!size)
-               return -EINVAL;
-
        mtree_lock(mt);
 retry:
-       mas.offset = 0;
-       mas.index = min;
-       mas.last = max - size + 1;
-       ret = mas_alloc(&mas, entry, size, startp);
+       ret = mas_empty_area(&mas, min, max, size);
+       if (ret)
+               goto unlock;
+
+       mas_insert(&mas, entry);
+       /*
+        * mas_nomem() may release the lock, causing the allocated area
+        * to be unavailable, so try to allocate a free area again.
+        */
        if (mas_nomem(&mas, gfp))
                goto retry;
 
+       if (mas_is_err(&mas))
+               ret = xa_err(mas.node);
+       else
+               *startp = mas.index;
+
+unlock:
        mtree_unlock(mt);
        return ret;
 }
@@ -6529,28 +6531,33 @@ int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp,
 {
        int ret = 0;
 
-       MA_STATE(mas, mt, min, max - size + 1);
+       MA_STATE(mas, mt, 0, 0);
        if (!mt_is_alloc(mt))
                return -EINVAL;
 
        if (WARN_ON_ONCE(mt_is_reserved(entry)))
                return -EINVAL;
 
-       if (min > max)
-               return -EINVAL;
-
-       if (max < size - 1)
-               return -EINVAL;
-
-       if (!size)
-               return -EINVAL;
-
        mtree_lock(mt);
 retry:
-       ret = mas_rev_alloc(&mas, min, max, entry, size, startp);
+       ret = mas_empty_area_rev(&mas, min, max, size);
+       if (ret)
+               goto unlock;
+
+       mas_insert(&mas, entry);
+       /*
+        * mas_nomem() may release the lock, causing the allocated area
+        * to be unavailable, so try to allocate a free area again.
+        */
        if (mas_nomem(&mas, gfp))
                goto retry;
 
+       if (mas_is_err(&mas))
+               ret = xa_err(mas.node);
+       else
+               *startp = mas.index;
+
+unlock:
        mtree_unlock(mt);
        return ret;
 }