linux-kernel - [PATCH v4 31/40] m68k: optimize get_mmu

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Date: Thu, 20 Jun 2024 10:56:54 -0700
From: Yury Norov <yury.norov@...il.com>
To: linux-kernel@...r.kernel.org,
	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Hugh Dickins <hughd@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Yury Norov <yury.norov@...il.com>,
	linux-m68k@...ts.linux-m68k.org
Cc: Alexey Klimov <alexey.klimov@...aro.org>,
	Bart Van Assche <bvanassche@....org>,
	Jan Kara <jack@...e.cz>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Matthew Wilcox <willy@...radead.org>,
	Mirsad Todorovac <mirsad.todorovac@....unizg.hr>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Sergey Shtylyov <s.shtylyov@....ru>,
	Greg Ungerer <gerg@...ux-m68k.org>
Subject: [PATCH v4 31/40] m68k: optimize get_mmu_context()

get_mmu_context() opencodes atomic find_and_set_bit_wrap(). Simplify
it by using find_and_set_bit_wrap().

CC: Geert Uytterhoeven <geert@...ux-m68k.org>
Signed-off-by: Yury Norov <yury.norov@...il.com>
Acked-by: Greg Ungerer <gerg@...ux-m68k.org>
---
 arch/m68k/include/asm/mmu_context.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/m68k/include/asm/mmu_context.h b/arch/m68k/include/asm/mmu_context.h
index 141bbdfad960..2e61063aa621 100644
--- a/arch/m68k/include/asm/mmu_context.h
+++ b/arch/m68k/include/asm/mmu_context.h
@@ -3,6 +3,7 @@
 #define __M68K_MMU_CONTEXT_H
 
 #include <asm-generic/mm_hooks.h>
+#include <linux/find_atomic.h>
 #include <linux/mm_types.h>
 
 #ifdef CONFIG_MMU
@@ -35,12 +36,11 @@ static inline void get_mmu_context(struct mm_struct *mm)
 		atomic_inc(&nr_free_contexts);
 		steal_context();
 	}
-	ctx = next_mmu_context;
-	while (test_and_set_bit(ctx, context_map)) {
-		ctx = find_next_zero_bit(context_map, LAST_CONTEXT+1, ctx);
-		if (ctx > LAST_CONTEXT)
-			ctx = 0;
-	}
+
+	do {
+		ctx = find_and_set_bit_wrap(context_map, LAST_CONTEXT + 1, next_mmu_context);
+	} while (ctx > LAST_CONTEXT);
+
 	next_mmu_context = (ctx + 1) & LAST_CONTEXT;
 	mm->context = ctx;
 	context_mm[ctx] = mm;
-- 
2.43.0