maple_tree: Fix mas_prev issue with parent slot & loop at root.

parent slots were not being set correctly for the first ascend.  This
caused data to be skipped.

There was also an infinite loop if this was the first entry in a deep
tree.

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

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 37b4526001817ff91e5245c1eb7b0a63288c3fe3..69c63082c7d35e90bd868ff1b67c746702c27dc9 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -2814,16 +2814,15 @@ static inline void mas_prev_node(struct ma_state *mas, unsigned long limit)
        int slot;
        unsigned long start_piv;
 
-       slot = mas_get_slot(mas);
        start_piv = mas_get_safe_pivot(mas, slot);
 restart_prev_node:
        level = 0;
-       slot = mas_get_slot(mas);
        if (mte_is_root(mas->node) || mas->node == MAS_NONE)
                goto no_entry;
 
        while (1) {
                unsigned long min;
+               slot = mte_parent_slot(mas->node);
                mas_ascend(mas);
                level++;
 
@@ -2877,8 +2876,6 @@ restart_prev_node:
 ascend:
                if (mte_is_root(mas->node))
                        goto no_entry;
-
-               slot = mte_parent_slot(mas->node);
        }
 
 no_entry:
@@ -3244,6 +3241,9 @@ void *mas_prev(struct ma_state *mas, unsigned long min)
 
        do {
                entry = _mas_prev(mas, min);
+               if (!mas_searchable(mas))
+                       break;
+
        } while (!entry || mt_will_coalesce(entry));
 
        return entry;
@@ -3982,7 +3982,7 @@ static inline int mas_safe_slot(struct ma_state *mas, int *slot,
                        return false;
 
                entry = mte_get_rcu_slot(mas->node, (*slot) + delta);
-               if (!mt_is_empty(entry))
+               if (!mt_is_empty(entry) && !xa_is_retry(entry))
                        return true;
                *slot += delta;
        }

diff --git a/lib/test_maple_tree.c b/lib/test_maple_tree.c
index 6daa7a74ec992823faa94d83071c29aa4d22a935..c8a81ef5a28b5b504bd339f42273fbce111c6ac9 100644 (file)
--- a/lib/test_maple_tree.c
+++ b/lib/test_maple_tree.c
@@ -10331,6 +10331,275 @@ STORE, 140222968504320, 140222970597375,
 STORE, 140222970597376, 140222970605567,
 ERASE, 140222970597376, 140222970605567,
 STORE, 140222970597376, 140222970605567,
+       };
+       unsigned long set19[] = {
+STORE, 140737488347136, 140737488351231,
+STORE, 140725182459904, 140737488351231,
+SNULL, 140725182463999, 140737488351231,
+STORE, 140725182459904, 140725182463999,
+STORE, 140725182328832, 140725182463999,
+STORE, 94730166636544, 94730166763519,
+SNULL, 94730166747135, 94730166763519,
+STORE, 94730166636544, 94730166747135,
+STORE, 94730166747136, 94730166763519,
+ERASE, 94730166747136, 94730166763519,
+STORE, 94730166751232, 94730166763519,
+STORE, 140656834555904, 140656836808703,
+SNULL, 140656834699263, 140656836808703,
+STORE, 140656834555904, 140656834699263,
+STORE, 140656834699264, 140656836808703,
+ERASE, 140656834699264, 140656836808703,
+STORE, 140656836796416, 140656836804607,
+STORE, 140656836804608, 140656836808703,
+STORE, 140725183389696, 140725183393791,
+STORE, 140725183377408, 140725183389695,
+STORE, 140656836788224, 140656836796415,
+STORE, 140656832331776, 140656834555903,
+SNULL, 140656833982463, 140656834555903,
+STORE, 140656832331776, 140656833982463,
+STORE, 140656833982464, 140656834555903,
+SNULL, 140656833982464, 140656834551807,
+STORE, 140656834551808, 140656834555903,
+STORE, 140656833982464, 140656834551807,
+ERASE, 140656833982464, 140656834551807,
+STORE, 140656833982464, 140656834551807,
+ERASE, 140656834551808, 140656834555903,
+STORE, 140656834551808, 140656834555903,
+STORE, 140656836763648, 140656836788223,
+STORE, 140656830070784, 140656832331775,
+SNULL, 140656830070784, 140656830222335,
+STORE, 140656830222336, 140656832331775,
+STORE, 140656830070784, 140656830222335,
+SNULL, 140656832315391, 140656832331775,
+STORE, 140656830222336, 140656832315391,
+STORE, 140656832315392, 140656832331775,
+SNULL, 140656832315392, 140656832323583,
+STORE, 140656832323584, 140656832331775,
+STORE, 140656832315392, 140656832323583,
+ERASE, 140656832315392, 140656832323583,
+STORE, 140656832315392, 140656832323583,
+ERASE, 140656832323584, 140656832331775,
+STORE, 140656832323584, 140656832331775,
+STORE, 140656827940864, 140656830070783,
+SNULL, 140656827940864, 140656827969535,
+STORE, 140656827969536, 140656830070783,
+STORE, 140656827940864, 140656827969535,
+SNULL, 140656830062591, 140656830070783,
+STORE, 140656827969536, 140656830062591,
+STORE, 140656830062592, 140656830070783,
+ERASE, 140656830062592, 140656830070783,
+STORE, 140656830062592, 140656830070783,
+STORE, 140656825724928, 140656827940863,
+SNULL, 140656825724928, 140656825823231,
+STORE, 140656825823232, 140656827940863,
+STORE, 140656825724928, 140656825823231,
+SNULL, 140656827916287, 140656827940863,
+STORE, 140656825823232, 140656827916287,
+STORE, 140656827916288, 140656827940863,
+SNULL, 140656827916288, 140656827924479,
+STORE, 140656827924480, 140656827940863,
+STORE, 140656827916288, 140656827924479,
+ERASE, 140656827916288, 140656827924479,
+STORE, 140656827916288, 140656827924479,
+ERASE, 140656827924480, 140656827940863,
+STORE, 140656827924480, 140656827940863,
+STORE, 140656821927936, 140656825724927,
+SNULL, 140656821927936, 140656823586815,
+STORE, 140656823586816, 140656825724927,
+STORE, 140656821927936, 140656823586815,
+SNULL, 140656825683967, 140656825724927,
+STORE, 140656823586816, 140656825683967,
+STORE, 140656825683968, 140656825724927,
+SNULL, 140656825683968, 140656825708543,
+STORE, 140656825708544, 140656825724927,
+STORE, 140656825683968, 140656825708543,
+ERASE, 140656825683968, 140656825708543,
+STORE, 140656825683968, 140656825708543,
+ERASE, 140656825708544, 140656825724927,
+STORE, 140656825708544, 140656825724927,
+STORE, 140656819806208, 140656821927935,
+SNULL, 140656819806208, 140656819822591,
+STORE, 140656819822592, 140656821927935,
+STORE, 140656819806208, 140656819822591,
+SNULL, 140656821919743, 140656821927935,
+STORE, 140656819822592, 140656821919743,
+STORE, 140656821919744, 140656821927935,
+ERASE, 140656821919744, 140656821927935,
+STORE, 140656821919744, 140656821927935,
+STORE, 140656836755456, 140656836763647,
+STORE, 140656817553408, 140656819806207,
+SNULL, 140656817553408, 140656817704959,
+STORE, 140656817704960, 140656819806207,
+STORE, 140656817553408, 140656817704959,
+SNULL, 140656819798015, 140656819806207,
+STORE, 140656817704960, 140656819798015,
+STORE, 140656819798016, 140656819806207,
+ERASE, 140656819798016, 140656819806207,
+STORE, 140656819798016, 140656819806207,
+STORE, 140656815382528, 140656817553407,
+SNULL, 140656815382528, 140656815452159,
+STORE, 140656815452160, 140656817553407,
+STORE, 140656815382528, 140656815452159,
+SNULL, 140656817545215, 140656817553407,
+STORE, 140656815452160, 140656817545215,
+STORE, 140656817545216, 140656817553407,
+ERASE, 140656817545216, 140656817553407,
+STORE, 140656817545216, 140656817553407,
+STORE, 140656812171264, 140656815382527,
+SNULL, 140656812171264, 140656813248511,
+STORE, 140656813248512, 140656815382527,
+STORE, 140656812171264, 140656813248511,
+SNULL, 140656815345663, 140656815382527,
+STORE, 140656813248512, 140656815345663,
+STORE, 140656815345664, 140656815382527,
+ERASE, 140656815345664, 140656815382527,
+STORE, 140656815345664, 140656815382527,
+STORE, 140656810037248, 140656812171263,
+SNULL, 140656810037248, 140656810065919,
+STORE, 140656810065920, 140656812171263,
+STORE, 140656810037248, 140656810065919,
+SNULL, 140656812163071, 140656812171263,
+STORE, 140656810065920, 140656812163071,
+STORE, 140656812163072, 140656812171263,
+ERASE, 140656812163072, 140656812171263,
+STORE, 140656812163072, 140656812171263,
+STORE, 140656807727104, 140656810037247,
+SNULL, 140656807727104, 140656807931903,
+STORE, 140656807931904, 140656810037247,
+STORE, 140656807727104, 140656807931903,
+SNULL, 140656810029055, 140656810037247,
+STORE, 140656807931904, 140656810029055,
+STORE, 140656810029056, 140656810037247,
+ERASE, 140656810029056, 140656810037247,
+STORE, 140656810029056, 140656810037247,
+STORE, 140656805343232, 140656807727103,
+SNULL, 140656805343232, 140656805535743,
+STORE, 140656805535744, 140656807727103,
+STORE, 140656805343232, 140656805535743,
+SNULL, 140656807628799, 140656807727103,
+STORE, 140656805535744, 140656807628799,
+STORE, 140656807628800, 140656807727103,
+ERASE, 140656807628800, 140656807727103,
+STORE, 140656807628800, 140656807727103,
+STORE, 140656836747264, 140656836763647,
+STORE, 140656802775040, 140656805343231,
+SNULL, 140656802775040, 140656803241983,
+STORE, 140656803241984, 140656805343231,
+STORE, 140656802775040, 140656803241983,
+SNULL, 140656805335039, 140656805343231,
+STORE, 140656803241984, 140656805335039,
+STORE, 140656805335040, 140656805343231,
+ERASE, 140656805335040, 140656805343231,
+STORE, 140656805335040, 140656805343231,
+STORE, 140656800661504, 140656802775039,
+SNULL, 140656800661504, 140656800673791,
+STORE, 140656800673792, 140656802775039,
+STORE, 140656800661504, 140656800673791,
+SNULL, 140656802766847, 140656802775039,
+STORE, 140656800673792, 140656802766847,
+STORE, 140656802766848, 140656802775039,
+ERASE, 140656802766848, 140656802775039,
+STORE, 140656802766848, 140656802775039,
+STORE, 140656798482432, 140656800661503,
+SNULL, 140656798482432, 140656798560255,
+STORE, 140656798560256, 140656800661503,
+STORE, 140656798482432, 140656798560255,
+SNULL, 140656800653311, 140656800661503,
+STORE, 140656798560256, 140656800653311,
+STORE, 140656800653312, 140656800661503,
+ERASE, 140656800653312, 140656800661503,
+STORE, 140656800653312, 140656800661503,
+STORE, 140656796364800, 140656798482431,
+SNULL, 140656796364800, 140656796381183,
+STORE, 140656796381184, 140656798482431,
+STORE, 140656796364800, 140656796381183,
+SNULL, 140656798474239, 140656798482431,
+STORE, 140656796381184, 140656798474239,
+STORE, 140656798474240, 140656798482431,
+ERASE, 140656798474240, 140656798482431,
+STORE, 140656798474240, 140656798482431,
+STORE, 140656836739072, 140656836763647,
+STORE, 140656836726784, 140656836763647,
+SNULL, 140656825700351, 140656825708543,
+STORE, 140656825683968, 140656825700351,
+STORE, 140656825700352, 140656825708543,
+SNULL, 140656798478335, 140656798482431,
+STORE, 140656798474240, 140656798478335,
+STORE, 140656798478336, 140656798482431,
+SNULL, 140656800657407, 140656800661503,
+STORE, 140656800653312, 140656800657407,
+STORE, 140656800657408, 140656800661503,
+SNULL, 140656802770943, 140656802775039,
+STORE, 140656802766848, 140656802770943,
+STORE, 140656802770944, 140656802775039,
+SNULL, 140656827920383, 140656827924479,
+STORE, 140656827916288, 140656827920383,
+STORE, 140656827920384, 140656827924479,
+SNULL, 140656805339135, 140656805343231,
+STORE, 140656805335040, 140656805339135,
+STORE, 140656805339136, 140656805343231,
+SNULL, 140656807723007, 140656807727103,
+STORE, 140656807628800, 140656807723007,
+STORE, 140656807723008, 140656807727103,
+SNULL, 140656810033151, 140656810037247,
+STORE, 140656810029056, 140656810033151,
+STORE, 140656810033152, 140656810037247,
+SNULL, 140656812167167, 140656812171263,
+STORE, 140656812163072, 140656812167167,
+STORE, 140656812167168, 140656812171263,
+SNULL, 140656815353855, 140656815382527,
+STORE, 140656815345664, 140656815353855,
+STORE, 140656815353856, 140656815382527,
+SNULL, 140656817549311, 140656817553407,
+STORE, 140656817545216, 140656817549311,
+STORE, 140656817549312, 140656817553407,
+SNULL, 140656819802111, 140656819806207,
+STORE, 140656819798016, 140656819802111,
+STORE, 140656819802112, 140656819806207,
+SNULL, 140656821923839, 140656821927935,
+STORE, 140656821919744, 140656821923839,
+STORE, 140656821923840, 140656821927935,
+SNULL, 140656830066687, 140656830070783,
+STORE, 140656830062592, 140656830066687,
+STORE, 140656830066688, 140656830070783,
+SNULL, 140656832319487, 140656832323583,
+STORE, 140656832315392, 140656832319487,
+STORE, 140656832319488, 140656832323583,
+SNULL, 140656834547711, 140656834551807,
+STORE, 140656833982464, 140656834547711,
+STORE, 140656834547712, 140656834551807,
+SNULL, 94730166759423, 94730166763519,
+STORE, 94730166751232, 94730166759423,
+STORE, 94730166759424, 94730166763519,
+SNULL, 140656836800511, 140656836804607,
+STORE, 140656836796416, 140656836800511,
+STORE, 140656836800512, 140656836804607,
+ERASE, 140656836763648, 140656836788223,
+STORE, 94730171318272, 94730171453439,
+STORE, 140656836784128, 140656836788223,
+STORE, 140656836780032, 140656836784127,
+STORE, 140656791920640, 140656796364799,
+STORE, 140656836775936, 140656836780031,
+STORE, 140656787476480, 140656791920639,
+STORE, 140656779083776, 140656787476479,
+SNULL, 140656779087871, 140656787476479,
+STORE, 140656779083776, 140656779087871,
+STORE, 140656779087872, 140656787476479,
+STORE, 140656836771840, 140656836775935,
+STORE, 140656774639616, 140656779083775,
+STORE, 140656766246912, 140656774639615,
+SNULL, 140656766251007, 140656774639615,
+STORE, 140656766246912, 140656766251007,
+STORE, 140656766251008, 140656774639615,
+ERASE, 140656791920640, 140656796364799,
+ERASE, 140656836780032, 140656836784127,
+ERASE, 140656787476480, 140656791920639,
+ERASE, 140656836775936, 140656836780031,
+STORE, 140656836780032, 140656836784127,
+STORE, 140656791920640, 140656796364799,
+STORE, 140656836775936, 140656836780031,
+STORE, 140656787476480, 140656791920639,
+ERASE, 140656774639616, 140656779083775,
        };
        int cnt = 0;
        MA_STATE(mas, mt, 0, 0);
@@ -10466,9 +10735,28 @@ STORE, 140222970597376, 140222970605567,
        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);
+
+       /* set19 found 2 bugs in prev.
+        * 1. If we hit root without finding anything, then there was an
+        *    infinite loop.
+        * 2. The first ascending wasn't using the correct slot which may have
+        *    have caused missed entries.
+        */
+       mt_set_non_kernel(99);
+       mas_reset(&mas);
+       mtree_init(mt, MAPLE_ALLOC_RANGE);
+       check_erase2_testset(mt, set19, ARRAY_SIZE(set19));
+       rcu_barrier();
+       mt_dump(mt);
+       mas.index = 140656779083776;
+       entry = mas_find(&mas, ULONG_MAX);
+       MT_BUG_ON(mt, entry != xa_mk_value(140656779083776));
+       entry = mas_prev(&mas, 0);
+       MT_BUG_ON(mt, entry != xa_mk_value(140656766251008));
+
+       mtree_destroy(mt);
 }
 
 static noinline void check_alloc_rev_range(struct maple_tree *mt)