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From: david.laight.linux@gmail.com
To: Yury Norov <yury.norov@gmail.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Crt Mori <cmo@melexis.com>,
	Richard Genoud <richard.genoud@bootlin.com>,
	Andy Shevchenko <andriy.shevchenko@intel.com>,
	Luo Jie <quic_luoj@quicinc.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Jakub Kicinski <kuba@kernel.org>,
	netdev@vger.kernel.org, "David S . Miller" <davem@davemloft.net>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Andreas Noever <andreas.noever@gmail.com>,
	Yehezkel Bernat <YehezkelShB@gmail.com>,
	Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Cc: David Laight <david.laight.linux@gmail.com>
Subject: [PATCH v2 06/16] bitfield: Remove some pointless casts
Date: Fri, 12 Dec 2025 19:37:11 +0000	[thread overview]
Message-ID: <20251212193721.740055-7-david.laight.linux@gmail.com> (raw)
In-Reply-To: <20251212193721.740055-1-david.laight.linux@gmail.com>

From: David Laight <david.laight.linux@gmail.com>

Now that _val is always large enough to hold _mask there is no need
to cast it before the shift left.

This also corrects the incorrect parenthesis in FIELD_FIT(),
unlikely to be a real problem.

For FIELD_GET() and FIELD_MAX() there is no point casting the
result of the shift to the type of mask.
Even if mask were char/short the value will immediately be promoted
to 'signed int' as soon as it is used.
All that is likely to happen is an extra and with 0xff.

Remove the associated extra (...) around __auto_type variable.

Signed-off-by: David Laight <david.laight.linux@gmail.com>
---
 include/linux/bitfield.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h
index c30120535680..f1859e28df5d 100644
--- a/include/linux/bitfield.h
+++ b/include/linux/bitfield.h
@@ -88,13 +88,13 @@
 #define __FIELD_PREP(mask, val, pfx)					\
 	({								\
 		__BF_FIELD_CHECK_MASK(mask, val, pfx);			\
-		((typeof(mask))(val) << __bf_shf(mask)) & (mask);	\
+		((val) << __bf_shf(mask)) & (mask);			\
 	})
 
 #define __FIELD_GET(mask, reg, pfx)					\
 	({								\
 		__BF_FIELD_CHECK_MASK(mask, 0U, pfx);			\
-		(typeof(mask))(((reg) & (mask)) >> __bf_shf(mask));	\
+		((reg) & (mask)) >> __bf_shf(mask);			\
 	})
 
 /**
@@ -108,7 +108,7 @@
 	({								\
 		__auto_type _mask = mask;				\
 		__BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_MAX: ");	\
-		(typeof(_mask))((_mask) >> __bf_shf(_mask));		\
+		(_mask >> __bf_shf(_mask));				\
 	})
 
 /**
@@ -123,7 +123,7 @@
 		__auto_type _mask = mask;				\
 		__auto_type _val = 1 ? (val) : _mask;			\
 		__BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_FIT: ");	\
-		!((((typeof(_mask))_val) << __bf_shf(_mask)) & ~(_mask)); \
+		!((_val << __bf_shf(_mask)) & ~_mask);			\
 	})
 
 /**
@@ -201,7 +201,7 @@
 		typecheck_pointer(_reg_p);						\
 		__BF_FIELD_CHECK(_mask, *(_reg_p), _val, "FIELD_MODIFY: ");		\
 		*(_reg_p) &= ~(_mask);							\
-		*(_reg_p) |= (((typeof(_mask))(_val) << __bf_shf(_mask)) & (_mask));	\
+		*(_reg_p) |= (_val << __bf_shf(_mask)) & _mask;				\
 	})
 
 extern void __compiletime_error("value doesn't fit into mask")
-- 
2.39.5


  parent reply	other threads:[~2025-12-12 19:38 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-12 19:37 [PATCH v2 0/16] bitfield: tidy up bitfield.h david.laight.linux
2025-12-12 19:37 ` [PATCH v2 01/16] nfp: Call FIELD_PREP() in NFP_ETH_SET_BIT_CONFIG() wrapper david.laight.linux
2025-12-12 23:10   ` Jakub Kicinski
2025-12-12 19:37 ` [PATCH v2 02/16] thunderbolt: Don't pass a bitfield to FIELD_GET david.laight.linux
2025-12-13  2:28   ` Yury Norov
2025-12-13 10:01     ` David Laight
2025-12-13 22:14       ` David Laight
2025-12-12 19:37 ` [PATCH v2 03/16] bitmap: Use FIELD_PREP() in expansion of FIELD_PREP_WM16() david.laight.linux
2025-12-12 19:37 ` [PATCH v2 04/16] bitfield: Copy #define parameters to locals david.laight.linux
2025-12-12 19:37 ` [PATCH v2 05/16] bitfield: Merge __field_prep/get() into field_prep/get() david.laight.linux
2025-12-12 19:37 ` david.laight.linux [this message]
2025-12-12 19:37 ` [PATCH v2 07/16] bitfield: FIELD_MODIFY: Only do a single read/write on the target david.laight.linux
2025-12-12 19:37 ` [PATCH v2 08/16] bitfield: Simplify __BF_FIELD_CHECK_REG() david.laight.linux
2025-12-12 19:37 ` [PATCH v2 09/16] bitfield: Rename __FIELD_PREP/GET() to __BF_FIELD_PREP/GET() david.laight.linux
2025-12-12 19:37 ` [PATCH v2 10/16] bitfield: Split the 'val' check out of __BF_FIELD_CHECK_MASK() david.laight.linux
2025-12-12 19:37 ` [PATCH v2 11/16] bitfield: Common up validation of the mask parameter david.laight.linux
2025-12-14  6:19   ` kernel test robot
2025-12-14 13:17     ` David Laight
2025-12-12 19:37 ` [PATCH v2 12/16] bitfield: Remove leading _ from #define formal parameter names david.laight.linux
2025-12-12 19:37 ` [PATCH v2 13/16] bitfield: Reduce indentation david.laight.linux
2025-12-12 19:37 ` [PATCH v2 14/16] bitfield: Add comment block for the host/fixed endian functions david.laight.linux
2025-12-12 19:37 ` [PATCH v2 15/16] bitfield: Update comments for le/be functions david.laight.linux
2025-12-12 19:37 ` [PATCH v2 16/16] build_bug.h; Remove __BUILD_BUG_ON_NOT_POWER_OF_2() david.laight.linux

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