From 581de96fc30b7fe44070f17a8a73f3374d38d6ff Mon Sep 17 00:00:00 2001 From: Lukas Slebodnik Date: Tue, 10 Sep 2013 13:39:01 +0200 Subject: mmap_cache: Use two chains for hash collision. struct sss_mc_rec had two hash members (hash1 and hash2) but only one next member. This was a big problem in case of higher probability of hash collision. structure sss_mc_rec will have two next members (next1, next2) with this patch. next1 is related to hash1 and next2 is related to hash1. Iterating over chains is changed, because we need to choose right next pointer. Right next pointer will be chosen after comparing record hashes. This behaviour is wrapped in function sss_mc_next_slot_with_hash. Adding new record to chain is also changed. The situation is very similar to iterating. We need to choose right next pointer (next1 or next2). Right next pointer will be chosen after comparing record hashes. Adding reference to next slot is wrapped in function sss_mc_chain_slot_to_record_with_hash Size of structure sss_mc_rec was increased from 32 bytes to 40 bytes. Resolves: https://fedorahosted.org/sssd/ticket/2049 --- src/sss_client/nss_mc_group.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'src/sss_client/nss_mc_group.c') diff --git a/src/sss_client/nss_mc_group.c b/src/sss_client/nss_mc_group.c index 4e3d9fb0..5610233e 100644 --- a/src/sss_client/nss_mc_group.c +++ b/src/sss_client/nss_mc_group.c @@ -130,7 +130,7 @@ errno_t sss_nss_mc_getgrnam(const char *name, size_t name_len, /* check record matches what we are searching for */ if (hash != rec->hash1) { /* if name hash does not match we can skip this immediately */ - slot = rec->next; + slot = sss_nss_mc_next_slot_with_hash(rec, hash); continue; } @@ -152,7 +152,7 @@ errno_t sss_nss_mc_getgrnam(const char *name, size_t name_len, break; } - slot = rec->next; + slot = sss_nss_mc_next_slot_with_hash(rec, hash); } if (!MC_SLOT_WITHIN_BOUNDS(slot, gr_mc_ctx.dt_size)) { @@ -205,7 +205,7 @@ errno_t sss_nss_mc_getgrgid(gid_t gid, /* check record matches what we are searching for */ if (hash != rec->hash2) { /* if uid hash does not match we can skip this immediately */ - slot = rec->next; + slot = sss_nss_mc_next_slot_with_hash(rec, hash); continue; } @@ -214,7 +214,7 @@ errno_t sss_nss_mc_getgrgid(gid_t gid, break; } - slot = rec->next; + slot = sss_nss_mc_next_slot_with_hash(rec, hash); } if (!MC_SLOT_WITHIN_BOUNDS(slot, gr_mc_ctx.dt_size)) { -- cgit