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From: Ian Rogers <irogers@google.com>
To: Yury Norov <yury.norov@gmail.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	 Arnd Bergmann <arnd@arndb.de>,
	Nathan Chancellor <nathan@kernel.org>,
	 Nick Desaulniers <nick.desaulniers+lkml@gmail.com>,
	Bill Wendling <morbo@google.com>,
	 Justin Stitt <justinstitt@google.com>,
	Ian Rogers <irogers@google.com>,
	 Adrian Hunter <adrian.hunter@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	 Jakub Kicinski <kuba@kernel.org>,
	Jacob Keller <jacob.e.keller@intel.com>,
	linux-arch@vger.kernel.org,  linux-kernel@vger.kernel.org,
	llvm@lists.linux.dev
Subject: [PATCH v1 2/5] bitmap: Silence a clang -Wshorten-64-to-32 warning
Date: Thu,  3 Apr 2025 09:56:59 -0700	[thread overview]
Message-ID: <20250403165702.396388-3-irogers@google.com> (raw)
In-Reply-To: <20250403165702.396388-1-irogers@google.com>

The clang warning -Wshorten-64-to-32 can be useful to catch
inadvertent truncation. In some instances this truncation can lead to
changing the sign of a result, for example, truncation to return an
int to fit a sort routine. Silence the warning by making the implicit
truncation explicit.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 include/linux/bitmap.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 595217b7a6e7..4395e0a618f4 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -442,7 +442,7 @@ static __always_inline
 unsigned int bitmap_weight(const unsigned long *src, unsigned int nbits)
 {
 	if (small_const_nbits(nbits))
-		return hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
+		return (int)hweight_long(*src & BITMAP_LAST_WORD_MASK(nbits));
 	return __bitmap_weight(src, nbits);
 }
 
-- 
2.49.0.504.g3bcea36a83-goog


  parent reply	other threads:[~2025-04-03 16:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-03 16:56 [PATCH v1 0/5] Silence some clang -Wshorten-64-to-32 warnings Ian Rogers
2025-04-03 16:56 ` [PATCH v1 1/5] bitfield: Silence a clang -Wshorten-64-to-32 warning Ian Rogers
2025-04-03 16:56 ` Ian Rogers [this message]
2025-04-04  5:49   ` [PATCH v1 2/5] bitmap: " Arnd Bergmann
2025-04-04 11:31     ` Ian Rogers
2025-04-03 16:57 ` [PATCH v1 3/5] bitops: " Ian Rogers
2025-04-04  5:43   ` Arnd Bergmann
2025-04-04 11:35     ` Ian Rogers
2025-04-03 16:57 ` [PATCH v1 4/5] math64: " Ian Rogers
2025-04-03 16:57 ` [PATCH v1 5/5] hash.h: " Ian Rogers

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