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a=rsa-sha256; c=relaxed/relaxed; d=mailbox.org; s=mail20150812; t=1758670947; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=v0tO2Xj2ANtxwUz+K9Ts0AqWNrmWxz9Ns88vd8fr+ts=; b=OianGu9jHaLhKjjXNf1fTjhbivWz7aNm/Y6mKQBB/7V3CswSDOAHWxrzpEkU2h0Id//Sk7 17t6eboiPbGpQ2yfwf01wy0E9/gLD4qmg4lV1pqFrV+bP3LshOWUKbT7E53GYPVUdCPBIp U01Mau4bxeKZIQOd2S5+QoeuukRsTu60F6vNKQV64vlt0lZ9vtPWN/j8hF2W8OumyyCFwf yrIF9TV3r06qpbo9wqGsRtdIgX7vbMRIxRw/JcmL1jbDcZiiiiTi+BbZ6c+Ace6cq9RYum Fom7IQPEq6J1rrLWzVhgqHjFWL8VtJgEb1pVncP/Hrarhn/b5zcq0fnIsKu6cg== Date: Wed, 24 Sep 2025 01:42:24 +0200 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH] PCI: rcar-host: Add static assertion to check !PCI_LOCKLESS_CONFIG From: Marek Vasut To: Geert Uytterhoeven , Marek Vasut Cc: linux-pci@vger.kernel.org, =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , Bjorn Helgaas , Geert Uytterhoeven , Lorenzo Pieralisi , Magnus Damm , Manivannan Sadhasivam , Marek Vasut , Rob Herring , Yoshihiro Shimoda , linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org References: <20250922153352.99197-1-marek.vasut+renesas@mailbox.org> <974b6f7f-e769-48ff-9bd9-0ed0c8f48b1e@mailbox.org> Content-Language: en-US In-Reply-To: <974b6f7f-e769-48ff-9bd9-0ed0c8f48b1e@mailbox.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-MBO-RS-ID: ffada4ad991afe6718a X-MBO-RS-META: nwjtf1iw9sxucig7h1wrcutk8mbxmfut X-Rspamd-Queue-Id: 4cWc391br4z9smg On 9/22/25 5:48 PM, Marek Vasut wrote: Hello Geert, >>> +/* >>> + * This driver can not function correctly without PCIe subsystem level >>> + * config space access serialization. In case PCI_LOCKLESS_CONFIG is >>> + * ever enabled on ARM, complain loudly so the driver can be updated >>> + * accordingly. >>> + */ >>> +static_assert(!IS_ENABLED(CONFIG_PCI_LOCKLESS_CONFIG)); >>> + >>>   struct rcar_msi { >>>          DECLARE_BITMAP(used, INT_PCI_MSI_NR); >>>          struct irq_domain *domain; >> >> This causes a build failure when compile-testing, e.g. x86 allmodconfig. >> Using "depends on !PCI_LOCKLESS_CONFIG" instead would avoid that, >> but indeed has the disadvantage that it wouldn't complain loudly when >> PCI_LOCKLESS_CONFIG would ever be enabled on ARM64... > All right, let's also wait for input from PCI maintainers. It seems both > alternatives -- static_assert() and !PCI_LOCKLESS_CONFIG have their own > disadvantages, maybe there is a third option. Maybe we can try with both. -- Best regards, Marek Vasut