linux-kernel - [PATCH] lib/find: optimize find_*_bit

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Message-Id: <20231028190530.286300-1-yury.norov@gmail.com>
Date:   Sat, 28 Oct 2023 12:05:29 -0700
From:   Yury Norov <yury.norov@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     Yury Norov <yury.norov@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>
Subject: [PATCH] lib/find: optimize find_*_bit_wrap

When an offset is 0, there's no need to search a bitmap from the
beginning after the 1st search failed, because each bit has already
been tested.

Signed-off-by: Yury Norov <yury.norov@...il.com>
---
 include/linux/find.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/find.h b/include/linux/find.h
index 5e4f39ef2e72..241b6d028eda 100644
--- a/include/linux/find.h
+++ b/include/linux/find.h
@@ -405,7 +405,7 @@ unsigned long find_next_and_bit_wrap(const unsigned long *addr1,
 {
 	unsigned long bit = find_next_and_bit(addr1, addr2, size, offset);
 
-	if (bit < size)
+	if (bit < size || offset == 0)
 		return bit;
 
 	bit = find_first_and_bit(addr1, addr2, offset);
@@ -427,7 +427,7 @@ unsigned long find_next_bit_wrap(const unsigned long *addr,
 {
 	unsigned long bit = find_next_bit(addr, size, offset);
 
-	if (bit < size)
+	if (bit < size || offset == 0)
 		return bit;
 
 	bit = find_first_bit(addr, offset);
-- 
2.39.2