From 73bd1227787bfe73eea3d04c63a89cb55db9c23e Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sat, 18 Apr 2026 09:41:21 +0800 Subject: rhashtable: Restore insecure_elasticity toggle Some users of rhashtable cannot handle insertion failures, and are happy to accept the consequences of a hash table that having very long chains. Restore the insecure_elasticity toggle for these users. In addition to disabling the chain length checks, this also removes the emergency resize that would otherwise occur when the hash table occupancy hits 100% (an async resize is still scheduled at 75%). Signed-off-by: Herbert Xu Signed-off-by: Tejun Heo --- include/linux/rhashtable-types.h | 2 ++ include/linux/rhashtable.h | 5 +++-- 2 files changed, 5 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/rhashtable-types.h b/include/linux/rhashtable-types.h index 015c8298bebc..72082428d6c6 100644 --- a/include/linux/rhashtable-types.h +++ b/include/linux/rhashtable-types.h @@ -49,6 +49,7 @@ typedef int (*rht_obj_cmpfn_t)(struct rhashtable_compare_arg *arg, * @head_offset: Offset of rhash_head in struct to be hashed * @max_size: Maximum size while expanding * @min_size: Minimum size while shrinking + * @insecure_elasticity: Set to true to disable chain length checks * @automatic_shrinking: Enable automatic shrinking of tables * @hashfn: Hash function (default: jhash2 if !(key_len % 4), or jhash) * @obj_hashfn: Function to hash object @@ -61,6 +62,7 @@ struct rhashtable_params { u16 head_offset; unsigned int max_size; u16 min_size; + bool insecure_elasticity; bool automatic_shrinking; rht_hashfn_t hashfn; rht_obj_hashfn_t obj_hashfn; diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index 0480509a6339..7def3f0f556b 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -821,14 +821,15 @@ slow_path: goto out; } - if (elasticity <= 0) + if (elasticity <= 0 && !params.insecure_elasticity) goto slow_path; data = ERR_PTR(-E2BIG); if (unlikely(rht_grow_above_max(ht, tbl))) goto out_unlock; - if (unlikely(rht_grow_above_100(ht, tbl))) + if (unlikely(rht_grow_above_100(ht, tbl)) && + !params.insecure_elasticity) goto slow_path; /* Inserting at head of list makes unlocking free. */ -- cgit v1.2.3