linux-kernel - [PATCH 3/3] mm/swap: remove redundant check for swap_slot_cache

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Date:   Thu, 30 Apr 2020 14:11:43 +0800
From:   Zhen Lei <thunder.leizhen@...wei.com>
To:     Tim Chen <tim.c.chen@...ux.intel.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-mm <linux-mm@...ck.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
CC:     Zhen Lei <thunder.leizhen@...wei.com>
Subject: [PATCH 3/3] mm/swap: remove redundant check for swap_slot_cache_initialized

Because enable_swap_slots_cache can only become true in
enable_swap_slots_cache(), and depends on swap_slot_cache_initialized is
true before. That means, when enable_swap_slots_cache is true,
swap_slot_cache_initialized is true also.

So the condition:
"swap_slot_cache_enabled && swap_slot_cache_initialized"
can be reduced to "swap_slot_cache_enabled"

And in mathematics:
"!swap_slot_cache_enabled || !swap_slot_cache_initialized"
is equal to "!(swap_slot_cache_enabled && swap_slot_cache_initialized)"

So no functional change.

Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
---
 mm/swap_slots.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/mm/swap_slots.c b/mm/swap_slots.c
index b40394473a3c..3e6453573a89 100644
--- a/mm/swap_slots.c
+++ b/mm/swap_slots.c
@@ -46,8 +46,7 @@ static void __drain_swap_slots_cache(unsigned int type);
 static void deactivate_swap_slots_cache(void);
 static void reactivate_swap_slots_cache(void);
 
-#define use_swap_slot_cache (swap_slot_cache_active && \
-		swap_slot_cache_enabled && swap_slot_cache_initialized)
+#define use_swap_slot_cache (swap_slot_cache_active && swap_slot_cache_enabled)
 #define SLOTS_CACHE 0x1
 #define SLOTS_CACHE_RET 0x2
 
@@ -94,7 +93,7 @@ static bool check_cache_active(void)
 {
 	long pages;
 
-	if (!swap_slot_cache_enabled || !swap_slot_cache_initialized)
+	if (!swap_slot_cache_enabled)
 		return false;
 
 	pages = get_nr_swap_pages();
-- 
2.26.0.106.g9fadedd