Linux PCI subsystem development
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From: Oliver Neukum <oneukum@suse.com>
To: Oliver Neukum <oneukum@suse.com>,
	Alexander Stein <alexander.stein@ew.tq-group.com>,
	Bjorn Helgaas <bhelgaas@google.com>
Cc: Korneliusz Osmenda <korneliuszo@gmail.com>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/1] Guard pci_create_sysfs_dev_files with atomic value
Date: Tue, 21 Mar 2023 10:09:22 +0100	[thread overview]
Message-ID: <a1cca367-52b6-a6b1-fb01-890cad39fd29@suse.com> (raw)
In-Reply-To: <ced8713f-69de-e48a-37eb-4f844e651b6b@suse.com>

Am Donnerstag, 16. März 2023, 15:01:25 CET schrieb Oliver Neukum:
> I'm not sure if I can follow you here. Can you elaborate?

There are far better reasons to leave the setup of a PCI bus as the firmware
has done it than to leave a USB as is.


> How is it necessary? How do these PCI devices get attaches to the pci_bus_type 
> bus without calling pci_bus_add_device?

AFAICT they don't. But somebody has to call it.


> Okay, so which dependency is provided by pci_sysfs_init, which are required by 
> drivers then?

It isn't. It is missing from the code. But it exists in reality. That is the point.
You have a race condition between two probes. We cannot have that.
Hence IMHO the dependency would be best expressed by waiting for pci_sysfs_init()
to finish in the init sequence before you add any PCI bridges or devices to the system.

	Regards
		Oliver

      parent reply	other threads:[~2023-03-21  9:09 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-16  9:15 [PATCH v2 1/1] Guard pci_create_sysfs_dev_files with atomic value Alexander Stein
2023-03-16  9:18 ` Alexander Stein
2023-03-16  9:23 ` Oliver Neukum
2023-03-16  9:33   ` Alexander Stein
2023-03-16 11:17     ` Oliver Neukum
2023-03-16 11:58       ` Alexander Stein
2023-03-16 12:23         ` Oliver Neukum
2023-03-16 13:16           ` Alexander Stein
2023-03-16 14:01             ` Oliver Neukum
2023-03-16 15:00               ` Alexander Stein
2023-03-21  9:09               ` Oliver Neukum [this message]

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