linux-kernel - [PATCH v1 2/5] bitmap: Silence a clang -Wshorten-64-to-32 warning

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Message-ID: <20250403165702.396388-3-irogers@google.com>
Date: Thu,  3 Apr 2025 09:56:59 -0700
From: Ian Rogers <irogers@...gle.com>
To: Yury Norov <yury.norov@...il.com>, Rasmus Villemoes <linux@...musvillemoes.dk>, 
	Arnd Bergmann <arnd@...db.de>, Nathan Chancellor <nathan@...nel.org>, 
	Nick Desaulniers <nick.desaulniers+lkml@...il.com>, Bill Wendling <morbo@...gle.com>, 
	Justin Stitt <justinstitt@...gle.com>, Ian Rogers <irogers@...gle.com>, 
	Adrian Hunter <adrian.hunter@...el.com>, Thomas Gleixner <tglx@...utronix.de>, 
	Jakub Kicinski <kuba@...nel.org>, Jacob Keller <jacob.e.keller@...el.com>, linux-arch@...r.kernel.org, 
	linux-kernel@...r.kernel.org, llvm@...ts.linux.dev
Subject: [PATCH v1 2/5] bitmap: Silence a clang -Wshorten-64-to-32 warning

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@...gle.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