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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
	linux-arch@vger.kernel.org, torvalds@linux-foundation.org,
	npiggin@gmail.com
Subject: [PATCH v2 12/17] riscv: Implement xor_unlock_is_negative_byte
Date: Wed,  4 Oct 2023 17:53:12 +0100	[thread overview]
Message-ID: <20231004165317.1061855-13-willy@infradead.org> (raw)
In-Reply-To: <20231004165317.1061855-1-willy@infradead.org>

Inspired by the riscv clear_bit_unlock(), this will surely be
more efficient than the generic one defined in filemap.c.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 arch/riscv/include/asm/bitops.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/riscv/include/asm/bitops.h b/arch/riscv/include/asm/bitops.h
index 3540b690944b..15e3044298a2 100644
--- a/arch/riscv/include/asm/bitops.h
+++ b/arch/riscv/include/asm/bitops.h
@@ -191,6 +191,19 @@ static inline void __clear_bit_unlock(
 	clear_bit_unlock(nr, addr);
 }
 
+static inline bool xor_unlock_is_negative_byte(unsigned long mask,
+		volatile unsigned long *addr)
+{
+	unsigned long res;
+	__asm__ __volatile__ (
+		__AMO(xor) ".rl %0, %2, %1"
+		: "=r" (res), "+A" (*addr)
+		: "r" (__NOP(mask))
+		: "memory");
+	return (res & BIT(7)) != 0;
+}
+#define xor_unlock_is_negative_byte xor_unlock_is_negative_byte
+
 #undef __test_and_op_bit
 #undef __op_bit
 #undef __NOP
-- 
2.40.1


  parent reply	other threads:[~2023-10-04 16:53 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-04 16:53 [PATCH v2 00/17] Add folio_end_read Matthew Wilcox (Oracle)
2023-10-04 16:53 ` [PATCH v2 01/17] iomap: Hold state_lock over call to ifs_set_range_uptodate() Matthew Wilcox (Oracle)
2023-10-04 16:53 ` [PATCH v2 02/17] iomap: Protect read_bytes_pending with the state_lock Matthew Wilcox (Oracle)
2023-10-04 16:53 ` [PATCH v2 03/17] mm: Add folio_end_read() Matthew Wilcox (Oracle)
2024-02-23 15:26   ` Tetsuo Handa
2024-02-23 15:36     ` Matthew Wilcox
2023-10-04 16:53 ` [PATCH v2 04/17] ext4: Use folio_end_read() Matthew Wilcox (Oracle)
2023-10-04 16:53 ` [PATCH v2 05/17] buffer: " Matthew Wilcox (Oracle)
2023-10-04 16:53 ` [PATCH v2 06/17] iomap: " Matthew Wilcox (Oracle)
2023-10-04 16:53 ` [PATCH v2 07/17] bitops: Add xor_unlock_is_negative_byte() Matthew Wilcox (Oracle)
2023-10-04 16:53 ` [PATCH v2 08/17] alpha: Implement xor_unlock_is_negative_byte Matthew Wilcox (Oracle)
2023-10-04 16:53 ` [PATCH v2 09/17] m68k: " Matthew Wilcox (Oracle)
2023-10-04 23:49   ` Greg Ungerer
2023-10-05  8:11   ` Geert Uytterhoeven
2023-10-04 16:53 ` [PATCH v2 10/17] mips: " Matthew Wilcox (Oracle)
2023-10-04 16:53 ` [PATCH v2 11/17] powerpc: Implement arch_xor_unlock_is_negative_byte on 32-bit Matthew Wilcox (Oracle)
2023-10-04 16:53 ` Matthew Wilcox (Oracle) [this message]
2023-10-04 16:53 ` [PATCH v2 13/17] s390: Implement arch_xor_unlock_is_negative_byte Matthew Wilcox (Oracle)
2023-10-04 16:53 ` [PATCH v2 14/17] mm: Delete checks for xor_unlock_is_negative_byte() Matthew Wilcox (Oracle)
2023-10-05  8:12   ` Geert Uytterhoeven
2023-10-04 16:53 ` [PATCH v2 15/17] mm: Add folio_xor_flags_has_waiters() Matthew Wilcox (Oracle)
2023-10-04 16:53 ` [PATCH v2 16/17] mm: Make __end_folio_writeback() return void Matthew Wilcox (Oracle)
2023-10-04 16:53 ` [PATCH v2 17/17] mm: Use folio_xor_flags_has_waiters() in folio_end_writeback() Matthew Wilcox (Oracle)

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