linux-kernel - [PATCH] trace-cmd: add trace_hash_find

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <1450196004-1899-1-git-send-email-jbacik@fb.com>
Date:	Tue, 15 Dec 2015 11:13:24 -0500
From:	Josef Bacik <jbacik@...com>
To:	<kernel-team@...com>, <linux-kernel@...r.kernel.org>,
	<rostedt@...dmis.org>
Subject: [PATCH] trace-cmd: add trace_hash_find_reverse

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 <jbacik@...com>
---
 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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/