linux-kernel - [PATCH 11/15] mm/swap: add helper swap_offset

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]

Date:   Mon, 9 May 2022 21:14:12 +0800
From:   Miaohe Lin <linmiaohe@...wei.com>
To:     <akpm@...ux-foundation.org>
CC:     <willy@...radead.org>, <vbabka@...e.cz>, <dhowells@...hat.com>,
        <neilb@...e.de>, <apopple@...dia.com>, <david@...hat.com>,
        <surenb@...gle.com>, <peterx@...hat.com>,
        <naoya.horiguchi@....com>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>, <linmiaohe@...wei.com>
Subject: [PATCH 11/15] mm/swap: add helper swap_offset_available()

Add helper swap_offset_available() to remove some duplicated codes.
Minor readability improvement.

Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
 mm/swapfile.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index c90298a0561a..d5d3e2d03d28 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -776,6 +776,21 @@ static void set_cluster_next(struct swap_info_struct *si, unsigned long next)
 	this_cpu_write(*si->cluster_next_cpu, next);
 }
 
+static inline bool swap_offset_available(struct swap_info_struct *si, unsigned long offset)
+{
+	if (data_race(!si->swap_map[offset])) {
+		spin_lock(&si->lock);
+		return true;
+	}
+
+	if (vm_swap_full() && READ_ONCE(si->swap_map[offset]) == SWAP_HAS_CACHE) {
+		spin_lock(&si->lock);
+		return true;
+	}
+
+	return false;
+}
+
 static int scan_swap_map_slots(struct swap_info_struct *si,
 			       unsigned char usage, int nr,
 			       swp_entry_t slots[])
@@ -953,15 +968,8 @@ static int scan_swap_map_slots(struct swap_info_struct *si,
 scan:
 	spin_unlock(&si->lock);
 	while (++offset <= READ_ONCE(si->highest_bit)) {
-		if (data_race(!si->swap_map[offset])) {
-			spin_lock(&si->lock);
+		if (swap_offset_available(si, offset))
 			goto checks;
-		}
-		if (vm_swap_full() &&
-		    READ_ONCE(si->swap_map[offset]) == SWAP_HAS_CACHE) {
-			spin_lock(&si->lock);
-			goto checks;
-		}
 		if (unlikely(--latency_ration < 0)) {
 			cond_resched();
 			latency_ration = LATENCY_LIMIT;
@@ -970,15 +978,8 @@ static int scan_swap_map_slots(struct swap_info_struct *si,
 	}
 	offset = si->lowest_bit;
 	while (offset < scan_base) {
-		if (data_race(!si->swap_map[offset])) {
-			spin_lock(&si->lock);
+		if (swap_offset_available(si, offset))
 			goto checks;
-		}
-		if (vm_swap_full() &&
-		    READ_ONCE(si->swap_map[offset]) == SWAP_HAS_CACHE) {
-			spin_lock(&si->lock);
-			goto checks;
-		}
 		if (unlikely(--latency_ration < 0)) {
 			cond_resched();
 			latency_ration = LATENCY_LIMIT;
-- 
2.23.0