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Sat, 22 Nov 2025 09:37:59 +0000 Date: Sat, 22 Nov 2025 09:37:58 +0000 Message-ID: <87ms4eflvt.wl-maz@kernel.org> From: Marc Zyngier To: niliqiang Cc: sunilvl@ventanamicro.com, ajones@ventanamicro.com, anup@brainfault.org, apatel@ventanamicro.com, atishp@atishpatra.org, bjorn@kernel.org, conor+dt@kernel.org, deng.weixian@zte.com.cn, devicetree@vger.kernel.org, frowand.list@gmail.com, hu.yuye@zte.com.cn, krzysztof.kozlowski+dt@linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, ni.liqiang@zte.com.cn, palmer@dabbelt.com, paul.walmsley@sifive.com, robh+dt@kernel.org, saravanak@google.com, tglx@linutronix.de, dai.hualiang@zte.com.cn, liu.qingtao2@zte.com.cn, guo.chang2@zte.com.cn, wu.jiabao@zte.com.cn, liu.wenhong35@zte.com.cn Subject: Re: [PATCH v16 6/9] irqchip: Add RISC-V advanced PLIC driver for direct-mode In-Reply-To: <20251121135407.53372-1-ni_liqiang@126.com> References: <20251121135407.53372-1-ni_liqiang@126.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: ni_liqiang@126.com, sunilvl@ventanamicro.com, ajones@ventanamicro.com, anup@brainfault.org, apatel@ventanamicro.com, atishp@atishpatra.org, bjorn@kernel.org, conor+dt@kernel.org, deng.weixian@zte.com.cn, devicetree@vger.kernel.org, frowand.list@gmail.com, hu.yuye@zte.com.cn, krzysztof.kozlowski+dt@linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, ni.liqiang@zte.com.cn, palmer@dabbelt.com, paul.walmsley@sifive.com, robh+dt@kernel.org, saravanak@google.com, tglx@linutronix.de, dai.hualiang@zte.com.cn, liu.qingtao2@zte.com.cn, guo.chang2@zte.com.cn, wu.jiabao@zte.com.cn, liu.wenhong35@zte.com.cn X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251122_013805_557591_DB72627F X-CRM114-Status: GOOD ( 12.12 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, 21 Nov 2025 13:54:07 +0000, niliqiang wrote: > [...] > 2. But the OS enumerates them in random order upon each boot (first boot = sequence =E2=89=A0 second boot sequence) > first boot sequence ~ # dmesg |grep -i "PCI Root" > [ 8794.588531] ACPI: PCI Root Bridge [PC08] (domain 0006 [bus 80-ff]) > [ 8794.624478] ACPI: PCI Root Bridge [PC06] (domain 0005 [bus 00-ff]) > [ 8794.672741] ACPI: PCI Root Bridge [PC10] (domain 0008 [bus 00-ff]) > [ 8794.696680] ACPI: PCI Root Bridge [PC07] (domain 0006 [bus 00-7f]) > [ 8794.728234] ACPI: PCI Root Bridge [PC11] (domain 0009 [bus 00-ff]) > [ 8794.755098] ACPI: PCI Root Bridge [PC09] (domain 0007 [bus 00-ff]) > second boot sequence ~ # dmesg |grep -i "PCI Root" > [ 8794.588531] ACPI: PCI Root Bridge [PC09] (domain 0007 [bus 00-ff]) > [ 8794.624478] ACPI: PCI Root Bridge [PC06] (domain 0005 [bus 00-ff]) > [ 8794.672741] ACPI: PCI Root Bridge [PC08] (domain 0006 [bus 80-ff]) > [ 8794.696680] ACPI: PCI Root Bridge [PC11] (domain 0009 [bus 00-ff]) > [ 8794.728234] ACPI: PCI Root Bridge [PC07] (domain 0006 [bus 00-7f]) > [ 8794.755098] ACPI: PCI Root Bridge [PC10] (domain 0008 [bus 00-ff]) >=20 > This creates a critical issue: when NVMe devices are connected to > these host bridges, the unpredictable kernel scanning sequence > causes device identifiers (e.g., /dev/nvme0n1, /dev/nvme1n1) to > change across reboots. In server environments, such device naming > instability is unacceptable as it breaks storage configuration > reliability and consistency. You're barking up the wrong tree. It is *userspace*'s job to ensure this consistency. That's why udev exists. That's why device and partition UUIDs exist. In short, this isn't the kernel's job. The kernel gives you all the tools you need already. Thanks, M. --=20 Jazz isn't dead. It just smells funny.