From patchwork Fri Feb 23 09:01:46 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Berg X-Patchwork-Id: 13568755 X-Patchwork-Delegate: kvalo@adurom.com Received: from sipsolutions.net (s3.sipsolutions.net [168.119.38.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3CF2C18E0C for ; Fri, 23 Feb 2024 09:02:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=168.119.38.16 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708678923; cv=none; b=p37Jb/fAtRzspUTrfqv6nPtx6bM8QlxWfg1497dNytEOkyP70bNZyGfO5U6oRBrjZinv+EJryFQfMsjftpHCn41IFlWoSCEsGcKKjBAnumZOgdcp75/gmmCxRuQXJjNrM1bqx+Yj/qt4KBVwmzI+6fBS01GjL0wFqcxKBzHLMuM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708678923; c=relaxed/simple; bh=sqKbhMJzhsihxTtTEJ5J7MQ3m/Ho0hYEiMaMKAIFa2Y=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=WXjlYjVtUM7XLnpClv0yKHoBIaFEWP5BYdIPTEIL40JiqTxHqVELA/T8Qt9i2z2XXZowZMa7vdD1fxwwE6DR9+o3lXQ1S5dEh8JinAPQuqUdlz3JBbeYghTwWyUbjzZB3BsythjmKo//twkBl3GF5YDL6S3Zda62KwNt3AbiiN0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sipsolutions.net; spf=pass smtp.mailfrom=sipsolutions.net; dkim=pass (2048-bit key) header.d=sipsolutions.net header.i=@sipsolutions.net header.b=Yeg6aFkP; arc=none smtp.client-ip=168.119.38.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sipsolutions.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sipsolutions.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sipsolutions.net header.i=@sipsolutions.net header.b="Yeg6aFkP" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=Content-Transfer-Encoding:MIME-Version: Message-ID:Date:Subject:Cc:To:From:Content-Type:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-To:Resent-Cc: Resent-Message-ID:In-Reply-To:References; bh=NFnawQLqckakB5qhJof+/PNCBcsfRpomgyB1w5DcmpI=; t=1708678921; x=1709888521; b=Yeg6aFkPwhSZHOm6ER0xA2HA6SfAioUg5xW82S65tfjcAX6IDJJGhQSOtpvX0m82juRr0l/E10B fa1qlLd2nHQ+kjoXwJOO/TPtMAZD9J74KySSt4KK/5NHHfPRGQ0beUcADEP9/MJCcAV/TpvP4VcY2 IEyQhW7Tc1t5EvgTPYoyh1eX/NB5yFFRna4KdNFoZ3hnzJSvweDbU4XmZm0EL0d3dwoxR9xrHEU0P UldDhQPg2o6DKXpxaaH2G/phplUyT65unbMBTXQnn5M1U1x3RKzR5mXSWEei/6GLyomal9mI9bi+q qYP5VoR7h2+jxOa4OUXCiWLJqDR5wiDPiZYA==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.97) (envelope-from ) id 1rdRRG-00000004yKf-17gB; Fri, 23 Feb 2024 10:01:50 +0100 From: Johannes Berg To: linux-wireless@vger.kernel.org Cc: Felix Fietkau , Jeff Johnson , ath11k@lists.infradead.org, Johannes Berg Subject: [PATCH] bitfield: suppress "dubious: x & !y" sparse warning Date: Fri, 23 Feb 2024 10:01:46 +0100 Message-ID: <20240223100146.d243b6b1a9a1.I033828b1187c6bccf086e31400f7e933bb8373e7@changeid> X-Mailer: git-send-email 2.43.2 Precedence: bulk X-Mailing-List: linux-wireless@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Johannes Berg There's a somewhat common pattern of using FIELD_PREP() even for single bits, e.g. cmd->info1 |= FIELD_PREP(HTT_SRNG_SETUP_CMD_INFO1_RING_FLAGS_MSI_SWAP, !!(params.flags & HAL_SRNG_FLAGS_MSI_SWAP)); which might as well be written as if (params.flags & HAL_SRNG_FLAGS_MSI_SWAP) cmd->info1 |= HTT_SRNG_SETUP_CMD_INFO1_RING_FLAGS_MSI_SWAP; (since info1 is fully initialized to start with), but in a long chain of FIELD_PREP() this really seems fine. However, it triggers a sparse warning, in the check in the macro for whether a constant value fits into the mask, as this contains a "& (_val)". In this case, this really is always intentional, so just suppress the warning by adding "0+" to the expression, indicating explicitly that this is correct. Signed-off-by: Johannes Berg --- include/linux/bitfield.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h index ebfa12f69501..63928f173223 100644 --- a/include/linux/bitfield.h +++ b/include/linux/bitfield.h @@ -66,7 +66,8 @@ _pfx "mask is not constant"); \ BUILD_BUG_ON_MSG((_mask) == 0, _pfx "mask is zero"); \ BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \ - ~((_mask) >> __bf_shf(_mask)) & (_val) : 0, \ + ~((_mask) >> __bf_shf(_mask)) & \ + (0 + (_val)) : 0, \ _pfx "value too large for the field"); \ BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) > \ __bf_cast_unsigned(_reg, ~0ull), \