linux-kernel - [PATCH v2 05/10] mm: frontswap: split frontswap

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

Message-Id: <1339182919-11432-6-git-send-email-levinsasha928@gmail.com>
Date:	Fri,  8 Jun 2012 21:15:14 +0200
From:	Sasha Levin <levinsasha928@...il.com>
To:	dan.magenheimer@...cle.com, konrad.wilk@...cle.com
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	Sasha Levin <levinsasha928@...il.com>
Subject: [PATCH v2 05/10] mm: frontswap: split frontswap_shrink further to simplify locking

Split frontswap_shrink to simplify the locking in the original code.

Signed-off-by: Sasha Levin <levinsasha928@...il.com>
---
 mm/frontswap.c |   36 +++++++++++++++++++++---------------
 1 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/mm/frontswap.c b/mm/frontswap.c
index 5d9ed36..1f1af0e 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -265,6 +265,24 @@ static int __frontswap_unuse_pages(unsigned long total, unsigned long *unused,
 	return ret;
 }
 
+static int __frontswap_shrink(unsigned long target_pages,
+				unsigned long *pages_to_unuse,
+				int *type)
+{
+	unsigned long total_pages = 0, total_pages_to_unuse;
+
+	lockdep_assert_held(&swap_lock);
+
+	total_pages = __frontswap_curr_pages();
+	if (total_pages <= target_pages) {
+		/* Nothing to do */
+		*pages_to_unuse = 0;
+		return 0;
+	}
+	total_pages_to_unuse = total_pages - target_pages;
+	return __frontswap_unuse_pages(total_pages_to_unuse, pages_to_unuse, type);
+}
+
 /*
  * Frontswap, like a true swap device, may unnecessarily retain pages
  * under certain circumstances; "shrink" frontswap is essentially a
@@ -275,10 +293,8 @@ static int __frontswap_unuse_pages(unsigned long total, unsigned long *unused,
  */
 void frontswap_shrink(unsigned long target_pages)
 {
-	unsigned long total_pages = 0, total_pages_to_unuse;
 	unsigned long pages_to_unuse = 0;
 	int type, ret;
-	bool locked = false;
 
 	/*
 	 * we don't want to hold swap_lock while doing a very
@@ -286,20 +302,10 @@ void frontswap_shrink(unsigned long target_pages)
 	 * so restart scan from swap_list.head each time
 	 */
 	spin_lock(&swap_lock);
-	locked = true;
-	total_pages = __frontswap_curr_pages();
-	if (total_pages <= target_pages)
-		goto out;
-	total_pages_to_unuse = total_pages - target_pages;
-	ret = __frontswap_unuse_pages(total_pages_to_unuse, &pages_to_unuse, &type);
-	if (ret < 0)
-		goto out;
-	locked = false;
+	ret = __frontswap_shrink(target_pages, &pages_to_unuse, &type);
 	spin_unlock(&swap_lock);
-	try_to_unuse(type, true, pages_to_unuse);
-out:
-	if (locked)
-		spin_unlock(&swap_lock);
+	if (ret == 0 && pages_to_unuse)
+		try_to_unuse(type, true, pages_to_unuse);
 	return;
 }
 EXPORT_SYMBOL(frontswap_shrink);
-- 
1.7.8.6

--
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/