maple_tree: Fix finding the end of a node when the node ends in a NULL.

Also fix the limit calculation on gaps when searches backwards goes into
adjacent nodes during the search.

Ignoring the end null may cause gaps to be skipped when searching
backwards.

Adjacent nodes caused the max limit to be reset to the parent but never
set if the very next entry also had a potential gap that would work.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 9eb4ccf0dd21815171e140da9d4c445685e87d1f..37b4526001817ff91e5245c1eb7b0a63288c3fe3 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -1157,8 +1157,8 @@ static inline unsigned char mas_data_end(const struct ma_state *mas,
                                        break;
                                }
                                (*coalesce) = (*coalesce) - counted_null + 1;
-                               slot -= counted_null;
-                               piv = _mas_get_safe_pivot(mas, slot, type);
+                               piv = _mas_get_safe_pivot(mas,
+                                               slot - counted_null, type);
                        }
                        break;
                }
@@ -3589,11 +3589,10 @@ static inline bool _mas_rev_awalk(struct ma_state *mas, unsigned long size)
        i = mas_get_slot(mas);
 
        min = mas->min;
-       max = mas->max;
+       max = _mas_get_safe_pivot(mas, i, type);
 
        switch (type) {
        case maple_leaf_64:
-               max = _mas_get_safe_pivot(mas, i, type);
                start = i;
 
                do {

diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
index ac73754cd3b5da905f89947fd11c4e5977a84227..6daa7a74ec992823faa94d83071c29aa4d22a935 100644 (file)
--- a/lib/test_maple_tree.c
+++ b/lib/test_maple_tree.c
@@ -10237,6 +10237,101 @@ STORE, 139921865613312, 139921865617407,
 STORE, 139921865547776, 139921865564159,
        };
 
+       unsigned long set17[] = {
+STORE, 94397057224704, 94397057646591,
+STORE, 94397057650688, 94397057691647,
+STORE, 94397057691648, 94397057695743,
+STORE, 94397075271680, 94397075406847,
+STORE, 139953169051648, 139953169063935,
+STORE, 139953169063936, 139953171156991,
+STORE, 139953171156992, 139953171161087,
+STORE, 139953171161088, 139953171165183,
+STORE, 139953171165184, 139953171632127,
+STORE, 139953171632128, 139953173725183,
+STORE, 139953173725184, 139953173729279,
+STORE, 139953173729280, 139953173733375,
+STORE, 139953173733376, 139953173749759,
+STORE, 139953173749760, 139953175842815,
+STORE, 139953175842816, 139953175846911,
+STORE, 139953175846912, 139953175851007,
+STORE, 139953175851008, 139953175867391,
+STORE, 139953175867392, 139953177960447,
+STORE, 139953177960448, 139953177964543,
+STORE, 139953177964544, 139953177968639,
+STORE, 139953177968640, 139953179627519,
+STORE, 139953179627520, 139953181724671,
+STORE, 139953181724672, 139953181741055,
+STORE, 139953181741056, 139953181749247,
+STORE, 139953181749248, 139953181765631,
+STORE, 139953181765632, 139953181863935,
+STORE, 139953181863936, 139953183956991,
+STORE, 139953183956992, 139953183961087,
+STORE, 139953183961088, 139953183965183,
+STORE, 139953183965184, 139953183981567,
+STORE, 139953183981568, 139953184010239,
+STORE, 139953184010240, 139953186103295,
+STORE, 139953186103296, 139953186107391,
+STORE, 139953186107392, 139953186111487,
+STORE, 139953186111488, 139953186263039,
+STORE, 139953186263040, 139953188356095,
+STORE, 139953188356096, 139953188360191,
+STORE, 139953188360192, 139953188364287,
+STORE, 139953188364288, 139953188372479,
+STORE, 139953188372480, 139953188462591,
+STORE, 139953188462592, 139953190555647,
+STORE, 139953190555648, 139953190559743,
+STORE, 139953190559744, 139953190563839,
+STORE, 139953190563840, 139953190830079,
+STORE, 139953190830080, 139953192923135,
+STORE, 139953192923136, 139953192939519,
+STORE, 139953192939520, 139953192943615,
+STORE, 139953192943616, 139953192947711,
+STORE, 139953192947712, 139953192976383,
+STORE, 139953192976384, 139953195073535,
+STORE, 139953195073536, 139953195077631,
+STORE, 139953195077632, 139953195081727,
+STORE, 139953195081728, 139953195225087,
+STORE, 139953197281280, 139953197318143,
+STORE, 139953197322240, 139953197326335,
+STORE, 139953197326336, 139953197330431,
+STORE, 139953197330432, 139953197334527,
+STORE, 140720477511680, 140720477646847,
+STORE, 140720478302208, 140720478314495,
+STORE, 140720478314496, 140720478318591,
+       };
+       unsigned long set18[] = {
+STORE, 140737488347136, 140737488351231,
+STORE, 140724953673728, 140737488351231,
+SNULL, 140724953677823, 140737488351231,
+STORE, 140724953673728, 140724953677823,
+STORE, 140724953542656, 140724953677823,
+STORE, 94675199266816, 94675199311871,
+SNULL, 94675199303679, 94675199311871,
+STORE, 94675199266816, 94675199303679,
+STORE, 94675199303680, 94675199311871,
+ERASE, 94675199303680, 94675199311871,
+STORE, 94675199303680, 94675199311871,
+STORE, 140222970605568, 140222972858367,
+SNULL, 140222970748927, 140222972858367,
+STORE, 140222970605568, 140222970748927,
+STORE, 140222970748928, 140222972858367,
+ERASE, 140222970748928, 140222972858367,
+STORE, 140222972846080, 140222972854271,
+STORE, 140222972854272, 140222972858367,
+STORE, 140724954365952, 140724954370047,
+STORE, 140724954353664, 140724954365951,
+STORE, 140222972841984, 140222972846079,
+STORE, 140222972833792, 140222972841983,
+STORE, 140222968475648, 140222970605567,
+SNULL, 140222968475648, 140222968504319,
+STORE, 140222968504320, 140222970605567,
+STORE, 140222968475648, 140222968504319,
+SNULL, 140222970597375, 140222970605567,
+STORE, 140222968504320, 140222970597375,
+STORE, 140222970597376, 140222970605567,
+ERASE, 140222970597376, 140222970605567,
+STORE, 140222970597376, 140222970605567,
+       };
        int cnt = 0;
        MA_STATE(mas, mt, 0, 0);
 
@@ -10345,9 +10440,35 @@ STORE, 139921865547776, 139921865564159,
        check_erase2_testset(mt, set16, ARRAY_SIZE(set16));
        rcu_barrier();
        mas_get_unmapped_area_rev(&mas, 4096, 139921865637888, 0x6000);
-       printk("Found %lu\n", mas.index);
        MT_BUG_ON(mt, mas.index != 139921865523200);
        mtree_destroy(mt);
+
+       /* set17 found a bug in walking backwards and not counting nulls at
+        * the end.  This could cause a gap to be missed if the null had any
+        * size.
+        */
+       mt_set_non_kernel(99);
+       mas_reset(&mas);
+       mtree_init(mt, MAPLE_ALLOC_RANGE);
+       check_erase2_testset(mt, set17, ARRAY_SIZE(set17));
+       rcu_barrier();
+       mas_get_unmapped_area_rev(&mas, 4096, 139953197334528, 0x1000);
+       MT_BUG_ON(mt, mas.index != 139953197318144);
+       mtree_destroy(mt);
+
+       /* set18 found a bug in walking backwards and not setting the max from
+        * the node, but using the parent node.  This was only an issue if the
+        * next slot in the parent had what we needed.
+        */
+       mt_set_non_kernel(99);
+       mas_reset(&mas);
+       mtree_init(mt, MAPLE_ALLOC_RANGE);
+       check_erase2_testset(mt, set18, ARRAY_SIZE(set18));
+       rcu_barrier();
+       mas_get_unmapped_area_rev(&mas, 4096, 140222972858368, 2215936);
+       printk("Found %lu\n", mas.index);
+       MT_BUG_ON(mt, mas.index != 140222966259712);
+       mtree_destroy(mt);
 }
 
 static noinline void check_alloc_rev_range(struct maple_tree *mt)