From: Lukas Wunner <lukas@wunner.de>
To: Keith Busch <kbusch@meta.com>
Cc: linux-pci@vger.kernel.org, bhelgaas@google.com,
"Keith Busch" <kbusch@kernel.org>,
"Jonathan Cameron" <Jonathan.Cameron@huawei.com>,
"Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Subject: Re: [PATCHv3 4/5] pci: walk bus recursively
Date: Mon, 11 Nov 2024 09:21:10 +0100 [thread overview]
Message-ID: <ZzG-dly2nGtTgNoC@wunner.de> (raw)
In-Reply-To: <20241022224851.340648-5-kbusch@meta.com>
On Tue, Oct 22, 2024 at 03:48:50PM -0700, Keith Busch wrote:
> The original implementation purposefully chose a non-recursive walk,
> presumably as a precaution on stack use. We do recursive bus walking in
> other places though. For example:
>
> pci_bus_resettable
> pci_stop_bus_device
> pci_remove_bus_device
> pci_bus_allocate_dev_resources
>
> So, recursive pci bus walking is well tested and safe, and the
> implementation is easier to follow. The motivation for changing it now
> is to make it easier to introduce finer grain locking in the future.
Hm, I find the loss of non-recursive bus walking regrettable.
If the solution proposed earlier today...
https://lore.kernel.org/all/ZzG5koPOn16KQ8uM@wunner.de/
... is workable and we find it doesn't need recursive bus walking,
perhaps we should consider reverting this change (which is now
e24eafdda271 on pci/locking).
Thanks,
Lukas
next prev parent reply other threads:[~2024-11-11 8:21 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-22 22:48 [PATCHv3 0/5] pci cleanup/prep patches Keith Busch
2024-10-22 22:48 ` [PATCHv3 1/5] pci: make pci_stop_dev concurrent safe Keith Busch
2024-11-07 14:06 ` Lukas Wunner
2024-11-07 15:56 ` Keith Busch
2024-11-11 7:20 ` Lukas Wunner
2024-10-22 22:48 ` [PATCHv3 2/5] pci: make pci_destroy_dev " Keith Busch
2024-10-22 22:48 ` [PATCHv3 3/5] pci: move the walk bus lock to where its needed Keith Busch
2024-10-22 22:48 ` [PATCHv3 4/5] pci: walk bus recursively Keith Busch
2024-11-11 8:21 ` Lukas Wunner [this message]
2024-10-22 22:48 ` [PATCHv3 5/5] pci: unexport pci_walk_bus_locked Keith Busch
2024-10-23 21:43 ` Bjorn Helgaas
2024-10-23 22:00 ` Keith Busch
2024-10-23 22:07 ` Bjorn Helgaas
2024-10-23 22:20 ` [PATCHv3 0/5] pci cleanup/prep patches Bjorn Helgaas
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