From d3dcf8eb615537526bd42ff27a081d46d337816e Mon Sep 17 00:00:00 2001 From: Paul Blakey Date: Sun, 4 Mar 2018 17:29:48 +0200 Subject: [PATCH 1/2] rhashtable: Fix rhlist duplicates insertion When inserting duplicate objects (those with the same key), current rhlist implementation messes up the chain pointers by updating the bucket pointer instead of prev next pointer to the newly inserted node. This causes missing elements on removal and travesal. Fix that by properly updating pprev pointer to point to the correct rhash_head next pointer. Issue: 1241076 Change-Id: I86b2c140bcb4aeb10b70a72a267ff590bb2b17e7 Fixes: ca26893f05e8 ('rhashtable: Add rhlist interface') Signed-off-by: Paul Blakey Acked-by: Herbert Xu Signed-off-by: David S. Miller --- include/linux/rhashtable.h | 4 +++- lib/rhashtable.c | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index c9df2527e0cd..668a21f04b09 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -766,8 +766,10 @@ static inline void *__rhashtable_insert_fast( if (!key || (params.obj_cmpfn ? params.obj_cmpfn(&arg, rht_obj(ht, head)) : - rhashtable_compare(&arg, rht_obj(ht, head)))) + rhashtable_compare(&arg, rht_obj(ht, head)))) { + pprev = &head->next; continue; + } data = rht_obj(ht, head); diff --git a/lib/rhashtable.c b/lib/rhashtable.c index 3825c30aaa36..47de025b6245 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -506,8 +506,10 @@ static void *rhashtable_lookup_one(struct rhashtable *ht, if (!key || (ht->p.obj_cmpfn ? ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) : - rhashtable_compare(&arg, rht_obj(ht, head)))) + rhashtable_compare(&arg, rht_obj(ht, head)))) { + pprev = &head->next; continue; + } if (!ht->rhlist) return rht_obj(ht, head); From 499ac3b60f657dae82055fc81c7b01e6242ac9bc Mon Sep 17 00:00:00 2001 From: Paul Blakey Date: Sun, 4 Mar 2018 17:29:49 +0200 Subject: [PATCH 2/2] test_rhashtable: add test case for rhltable with duplicate objects Tries to insert duplicates in the middle of bucket's chain: bucket 1: [[val 21 (tid=1)]] -> [[ val 1 (tid=2), val 1 (tid=0) ]] Reuses tid to distinguish the elements insertion order. Signed-off-by: Paul Blakey Acked-by: Herbert Xu Signed-off-by: David S. Miller --- lib/test_rhashtable.c | 134 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 134 insertions(+) diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c index 76d3667fdea2..f4000c137dbe 100644 --- a/lib/test_rhashtable.c +++ b/lib/test_rhashtable.c @@ -79,6 +79,21 @@ struct thread_data { struct test_obj *objs; }; +static u32 my_hashfn(const void *data, u32 len, u32 seed) +{ + const struct test_obj_rhl *obj = data; + + return (obj->value.id % 10) << RHT_HASH_RESERVED_SPACE; +} + +static int my_cmpfn(struct rhashtable_compare_arg *arg, const void *obj) +{ + const struct test_obj_rhl *test_obj = obj; + const struct test_obj_val *val = arg->key; + + return test_obj->value.id - val->id; +} + static struct rhashtable_params test_rht_params = { .head_offset = offsetof(struct test_obj, node), .key_offset = offsetof(struct test_obj, value), @@ -87,6 +102,17 @@ static struct rhashtable_params test_rht_params = { .nulls_base = (3U << RHT_BASE_SHIFT), }; +static struct rhashtable_params test_rht_params_dup = { + .head_offset = offsetof(struct test_obj_rhl, list_node), + .key_offset = offsetof(struct test_obj_rhl, value), + .key_len = sizeof(struct test_obj_val), + .hashfn = jhash, + .obj_hashfn = my_hashfn, + .obj_cmpfn = my_cmpfn, + .nelem_hint = 128, + .automatic_shrinking = false, +}; + static struct semaphore prestart_sem; static struct semaphore startup_sem = __SEMAPHORE_INITIALIZER(startup_sem, 0); @@ -465,6 +491,112 @@ static int __init test_rhashtable_max(struct test_obj *array, return err; } +static unsigned int __init print_ht(struct rhltable *rhlt) +{ + struct rhashtable *ht; + const struct bucket_table *tbl; + char buff[512] = ""; + unsigned int i, cnt = 0; + + ht = &rhlt->ht; + tbl = rht_dereference(ht->tbl, ht); + for (i = 0; i < tbl->size; i++) { + struct rhash_head *pos, *next; + struct test_obj_rhl *p; + + pos = rht_dereference(tbl->buckets[i], ht); + next = !rht_is_a_nulls(pos) ? rht_dereference(pos->next, ht) : NULL; + + if (!rht_is_a_nulls(pos)) { + sprintf(buff, "%s\nbucket[%d] -> ", buff, i); + } + + while (!rht_is_a_nulls(pos)) { + struct rhlist_head *list = container_of(pos, struct rhlist_head, rhead); + sprintf(buff, "%s[[", buff); + do { + pos = &list->rhead; + list = rht_dereference(list->next, ht); + p = rht_obj(ht, pos); + + sprintf(buff, "%s val %d (tid=%d)%s", buff, p->value.id, p->value.tid, + list? ", " : " "); + cnt++; + } while (list); + + pos = next, + next = !rht_is_a_nulls(pos) ? + rht_dereference(pos->next, ht) : NULL; + + sprintf(buff, "%s]]%s", buff, !rht_is_a_nulls(pos) ? " -> " : ""); + } + } + printk(KERN_ERR "\n---- ht: ----%s\n-------------\n", buff); + + return cnt; +} + +static int __init test_insert_dup(struct test_obj_rhl *rhl_test_objects, + int cnt, bool slow) +{ + struct rhltable rhlt; + unsigned int i, ret; + const char *key; + int err = 0; + + err = rhltable_init(&rhlt, &test_rht_params_dup); + if (WARN_ON(err)) + return err; + + for (i = 0; i < cnt; i++) { + rhl_test_objects[i].value.tid = i; + key = rht_obj(&rhlt.ht, &rhl_test_objects[i].list_node.rhead); + key += test_rht_params_dup.key_offset; + + if (slow) { + err = PTR_ERR(rhashtable_insert_slow(&rhlt.ht, key, + &rhl_test_objects[i].list_node.rhead)); + if (err == -EAGAIN) + err = 0; + } else + err = rhltable_insert(&rhlt, + &rhl_test_objects[i].list_node, + test_rht_params_dup); + if (WARN(err, "error %d on element %d/%d (%s)\n", err, i, cnt, slow? "slow" : "fast")) + goto skip_print; + } + + ret = print_ht(&rhlt); + WARN(ret != cnt, "missing rhltable elements (%d != %d, %s)\n", ret, cnt, slow? "slow" : "fast"); + +skip_print: + rhltable_destroy(&rhlt); + + return 0; +} + +static int __init test_insert_duplicates_run(void) +{ + struct test_obj_rhl rhl_test_objects[3] = {}; + + pr_info("test inserting duplicates\n"); + + /* two different values that map to same bucket */ + rhl_test_objects[0].value.id = 1; + rhl_test_objects[1].value.id = 21; + + /* and another duplicate with same as [0] value + * which will be second on the bucket list */ + rhl_test_objects[2].value.id = rhl_test_objects[0].value.id; + + test_insert_dup(rhl_test_objects, 2, false); + test_insert_dup(rhl_test_objects, 3, false); + test_insert_dup(rhl_test_objects, 2, true); + test_insert_dup(rhl_test_objects, 3, true); + + return 0; +} + static int thread_lookup_test(struct thread_data *tdata) { unsigned int entries = tdata->entries; @@ -613,6 +745,8 @@ static int __init test_rht_init(void) do_div(total_time, runs); pr_info("Average test time: %llu\n", total_time); + test_insert_duplicates_run(); + if (!tcount) return 0;