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[35.247.89.60]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-364a2732502sm41657a91.3.2026.04.28.12.45.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Apr 2026 12:45:53 -0700 (PDT) Date: Tue, 28 Apr 2026 12:45:48 -0700 From: Vipin Sharma To: David Matlack Cc: iommu@lists.linux.dev, kexec@lists.infradead.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Adithya Jayachandran , Alexander Graf , Alex Williamson , Bjorn Helgaas , Chris Li , David Rientjes , Jacob Pan , Jason Gunthorpe , Joerg Roedel , Jonathan Corbet , Josh Hilke , Leon Romanovsky , Lukas Wunner , Mike Rapoport , Parav Pandit , Pasha Tatashin , Pranjal Shrivastava , Pratyush Yadav , Robin Murphy , Saeed Mahameed , Samiullah Khawaja , Shuah Khan , Will Deacon , William Tu , Yi Liu Subject: Re: [PATCH v4 01/11] PCI: liveupdate: Set up FLB handler for the PCI core Message-ID: <20260428185242.GB3825533.vipinsh@google.com> References: <20260423212316.3431746-1-dmatlack@google.com> <20260423212316.3431746-2-dmatlack@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260423212316.3431746-2-dmatlack@google.com> X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 2133640003 X-Stat-Signature: foc3xyffpbrk5bxzi4jdcxtdfbytxpox X-Rspam-User: X-HE-Tag: 1777405555-491516 X-HE-Meta: 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 Xf9OxlHO hSBfQLoj2SnFfzbsIiXfLJDQti1kVbZqwmrHVbd+amfdyljvF9hYE1PH3rOdWv/s875Wes0y5xT+n2b+HhPVckDvBsWOfGokLnn11e0Ilx1+fzwIga5HyK0fk9CcO72J5Emac2Jcqd6cv2GxB4VTcVoOHx+ykV4NfUoZGP0bl3NIguujL2/4tsAFQxvsa66Zn96u/CEMbw9iSLlWvh6GBzDhP9s7zgaD1frMcsyp420b2qVOaiKx6n3upVZd3PQtD/TWKlmBc46733SY0fmFa+UHZDxHZEXGqlUFoAGYQGQBDhJS9WI1cXhdR1Hwil7kkGgcHSfVVwErNAg7hCRw+vgmDreNRXzrLNUnk4ioZvkpHXnEz+bWqAxX6RBZ1qEnfwSux/J3/zIT3ydPKWTrhcLQRfREsXv7o0Fr2EJ3LMzxigswgB4uWK0KZ5j5ZCW8mRhA3 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Apr 23, 2026 at 09:23:05PM +0000, David Matlack wrote: > + pr_debug("Preserving struct pci_ser with room for %u devices\n", > + max_nr_devices); > + > + ser = kho_alloc_preserve(size); > + if (IS_ERR(ser)) > + return PTR_ERR(ser); Should there be a similar pr_debug() in case of failure to denote that above "Preserving ..." message didn't finish, or, maybe just print one pr_debug() after the error check above? > +/** > + * struct pci_dev_ser - Serialized state about a single PCI device. > + * > + * @domain: The device's PCI domain number (segment). > + * @bdf: The device's PCI bus, device, and function number. > + * @reserved: Reserved (to naturally align struct pci_dev_ser). > + */ > +struct pci_dev_ser { > + u32 domain; > + u16 bdf; > + u16 reserved; Should this be renamed to 'u8 __padding[2];' instead? This will allow to just change the array length based on the need (0, 1, 2, 3). > +} __packed; > + > +/** > + * struct pci_ser - PCI Subsystem Live Update State > + * > + * This struct tracks state about all devices that are being preserved across > + * a Live Update for the next kernel. > + * > + * @max_nr_devices: The length of the devices[] flexible array. > + * @nr_devices: The number of devices that were preserved. > + * @devices: Flexible array of pci_dev_ser structs for each device. > + */ > +struct pci_ser { > + u32 max_nr_devices; > + u32 nr_devices; > + struct pci_dev_ser devices[]; > +} __packed; > + > +/* Ensure all elements of devices[] are naturally aligned. */ > +static_assert(offsetof(struct pci_ser, devices) % sizeof(unsigned long) == 0); > +static_assert(sizeof(struct pci_dev_ser) % sizeof(unsigned long) == 0); Nit: Maybe move this assert to be near to the definition of this struct, easier to find it when editing the struct vs finding it later during build.