linux-kernel - [PATCH 33/34] microblaze: rework get_mmu

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Date:   Sat, 18 Nov 2023 07:51:04 -0800
From:   Yury Norov <yury.norov@...il.com>
To:     linux-kernel@...r.kernel.org, Michal Simek <monstr@...str.eu>,
        Yury Norov <yury.norov@...il.com>
Cc:     Jan Kara <jack@...e.cz>,
        Mirsad Todorovac <mirsad.todorovac@....unizg.hr>,
        Matthew Wilcox <willy@...radead.org>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Maxim Kuvyrkov <maxim.kuvyrkov@...aro.org>,
        Alexey Klimov <klimov.linux@...il.com>
Subject: [PATCH 33/34] microblaze: rework get_mmu_context()

Fix opencoded find_and_set_bit_wrap(), which also suppresses potential
KCSAN warning.

Signed-off-by: Yury Norov <yury.norov@...il.com>
---
 arch/microblaze/include/asm/mmu_context_mm.h | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/microblaze/include/asm/mmu_context_mm.h b/arch/microblaze/include/asm/mmu_context_mm.h
index c2c77f708455..209c3a62353a 100644
--- a/arch/microblaze/include/asm/mmu_context_mm.h
+++ b/arch/microblaze/include/asm/mmu_context_mm.h
@@ -82,12 +82,11 @@ static inline void get_mmu_context(struct mm_struct *mm)
 		return;
 	while (atomic_dec_if_positive(&nr_free_contexts) < 0)
 		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;
-- 
2.39.2