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From: Matthew Wilcox <willy@infradead.org>
To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	linux-m68k@lists.linux-m68k.org
Subject: [PATCH v3 03/11] m68k: Add clear_bit_unlock_is_negative_byte implementation
Date: Thu, 16 Apr 2020 15:01:22 -0700	[thread overview]
Message-ID: <20200416220130.13343-4-willy@infradead.org> (raw)
In-Reply-To: <20200416220130.13343-1-willy@infradead.org>

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

This is the generic implementation.  Someone who knows m68k assembly
can probably do better (the BFCLR instruction appears to set the N bit
appropriately).

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-m68k@lists.linux-m68k.org
---
 arch/m68k/include/asm/bitops.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/m68k/include/asm/bitops.h b/arch/m68k/include/asm/bitops.h
index 10133a968c8e..bfb34e0748fe 100644
--- a/arch/m68k/include/asm/bitops.h
+++ b/arch/m68k/include/asm/bitops.h
@@ -524,6 +524,13 @@ static inline int __fls(int x)
 #define clear_bit_unlock	clear_bit
 #define __clear_bit_unlock	clear_bit_unlock
 
+static inline bool clear_bit_unlock_is_negative_byte(unsigned int nr,
+						volatile unsigned long *p)
+{
+	clear_bit_unlock(nr, p);
+	return test_bit(7, p);
+}
+
 #include <asm-generic/bitops/ext2-atomic.h>
 #include <asm-generic/bitops/le.h>
 #include <asm-generic/bitops/fls64.h>
-- 
2.25.1


  parent reply	other threads:[~2020-04-16 22:01 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-16 22:01 [PATCH v3 00/11] Make PageWriteback use the PageLocked optimisation Matthew Wilcox
2020-04-16 22:01 ` [PATCH v3 01/11] alpha: Add clear_bit_unlock_is_negative_byte implementation Matthew Wilcox
2020-04-16 22:01 ` [PATCH v3 02/11] ia64: " Matthew Wilcox
2020-04-16 22:01 ` Matthew Wilcox [this message]
2020-04-16 22:01 ` [PATCH v3 04/11] mips: " Matthew Wilcox
2020-04-16 22:01 ` [PATCH v3 05/11] riscv: " Matthew Wilcox
2020-04-16 22:01 ` [PATCH v3 06/11] s390: " Matthew Wilcox
2020-04-16 22:01 ` [PATCH v3 07/11] mm: Remove definition of clear_bit_unlock_is_negative_byte Matthew Wilcox
2020-04-16 22:01 ` [PATCH v3 08/11] mm: Move PG_writeback into the bottom byte Matthew Wilcox
2020-04-16 22:01 ` [PATCH v3 09/11] mm: Convert writeback BUG to WARN_ON Matthew Wilcox
2020-04-23 15:58   ` Jan Kara
2020-04-16 22:01 ` [PATCH v3 10/11] mm: Use clear_bit_unlock_is_negative_byte for PageWriteback Matthew Wilcox
2020-04-16 22:01 ` [PATCH v3 11/11] mm: Remove TestClearPageWriteback Matthew Wilcox
2020-04-17  7:28 ` [PATCH v3 00/11] Make PageWriteback use the PageLocked optimisation Geert Uytterhoeven
2020-04-17 11:12   ` Matthew Wilcox

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