From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754037AbbLOQNk (ORCPT ); Tue, 15 Dec 2015 11:13:40 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:47402 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753843AbbLOQNi (ORCPT ); Tue, 15 Dec 2015 11:13:38 -0500 From: Josef Bacik To: , , Subject: [PATCH] trace-cmd: add trace_hash_find_reverse Date: Tue, 15 Dec 2015 11:13:24 -0500 Message-ID: <1450196004-1899-1-git-send-email-jbacik@fb.com> X-Mailer: git-send-email 2.5.0 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [192.168.52.123] X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2015-12-15_07:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sometimes we want to FIFO identical entries in the hash table, so add trace_hash_find_reverse, which will cycle through the hash list in reverse. This is helpful in our case where we are monitoring block request issues to match with their corresponding completes, if we issue multiple times to the same block we want to be able to match them with the correct completes (more or less anyway). Thanks, Signed-off-by: Josef Bacik --- list.h | 5 +++++ trace-hash.c | 22 ++++++++++++++++++++++ 2 files changed, 27 insertions(+) diff --git a/list.h b/list.h index 9817871..93c64f5 100644 --- a/list.h +++ b/list.h @@ -79,4 +79,9 @@ static inline int list_empty(struct list_head *list) &(p)->field != list; \ p = n, n = container_of((p)->field.next, typeof(*p), field)) +#define list_for_each_entry_reverse(p, list, field) \ + for (p = container_of((list)->prev, typeof(*p), field); \ + &p->field != list; \ + p = container_of((p)->field.prev, typeof(*p), field)) + #endif /* __LIST_H */ diff --git a/trace-hash.c b/trace-hash.c index 5ffe61c..0dc4f73 100644 --- a/trace-hash.c +++ b/trace-hash.c @@ -94,3 +94,25 @@ trace_hash_find(struct trace_hash *hash, unsigned long long key, return NULL; } + +struct trace_hash_item * +trace_hash_find_reverse(struct trace_hash *hash, unsigned long long key, + trace_hash_func match, void *data) +{ + struct trace_hash_item *item; + struct list_head *bucket; + int bucket_nr = hash->power ? key & hash->power : + key % hash->nr_buckets; + + bucket = hash->buckets + bucket_nr; + list_for_each_entry_reverse(item, bucket, list) { + if (item->key == key) { + if (!match) + return item; + if (match(item, data)) + return item; + } + } + + return NULL; +} -- 2.5.0