[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [RFC PATCH 01/13] PCI: Prepare removing devres from pci_intx()
- To: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
- From: Philipp Stanner <pstanner@xxxxxxxxxx>
- Date: Fri, 11 Oct 2024 14:16:06 +0200
- Cc: Damien Le Moal <dlemoal@xxxxxxxxxx>, Niklas Cassel <cassel@xxxxxxxxxx>, Sergey Shtylyov <s.shtylyov@xxxxxx>, Basavaraj Natikar <basavaraj.natikar@xxxxxxx>, Jiri Kosina <jikos@xxxxxxxxxx>, Benjamin Tissoires <bentiss@xxxxxxxxxx>, Arnd Bergmann <arnd@xxxxxxxx>, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Alex Dubov <oakad@xxxxxxxxx>, Sudarsana Kalluru <skalluru@xxxxxxxxxxx>, Manish Chopra <manishc@xxxxxxxxxxx>, "David S. Miller" <davem@xxxxxxxxxxxxx>, Eric Dumazet <edumazet@xxxxxxxxxx>, Jakub Kicinski <kuba@xxxxxxxxxx>, Paolo Abeni <pabeni@xxxxxxxxxx>, Rasesh Mody <rmody@xxxxxxxxxxx>, GR-Linux-NIC-Dev@xxxxxxxxxxx, Igor Mitsyanko <imitsyanko@xxxxxxxxxxxxx>, Sergey Matyukevich <geomatsi@xxxxxxxxx>, Kalle Valo <kvalo@xxxxxxxxxx>, Sanjay R Mehta <sanju.mehta@xxxxxxx>, Shyam Sundar S K <Shyam-sundar.S-k@xxxxxxx>, Jon Mason <jdmason@xxxxxxxx>, Dave Jiang <dave.jiang@xxxxxxxxx>, Allen Hubbe <allenbh@xxxxxxxxx>, Bjorn Helgaas <bhelgaas@xxxxxxxxxx>, Alex Williamson <alex.williamson@xxxxxxxxxx>, Juergen Gross <jgross@xxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>, Jaroslav Kysela <perex@xxxxxxxx>, Takashi Iwai <tiwai@xxxxxxxx>, Mario Limonciello <mario.limonciello@xxxxxxx>, Chen Ni <nichen@xxxxxxxxxxx>, Ricky Wu <ricky_wu@xxxxxxxxxxx>, Al Viro <viro@xxxxxxxxxxxxxxxxxx>, Breno Leitao <leitao@xxxxxxxxxx>, Kevin Tian <kevin.tian@xxxxxxxxx>, Thomas Gleixner <tglx@xxxxxxxxxxxxx>, Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>, Mostafa Saleh <smostafa@xxxxxxxxxx>, Hannes Reinecke <hare@xxxxxxx>, John Garry <john.g.garry@xxxxxxxxxx>, Soumya Negi <soumya.negi97@xxxxxxxxx>, Jason Gunthorpe <jgg@xxxxxxxx>, Yi Liu <yi.l.liu@xxxxxxxxx>, "Dr. David Alan Gilbert" <linux@xxxxxxxxxxx>, Christian Brauner <brauner@xxxxxxxxxx>, Ankit Agrawal <ankita@xxxxxxxxxx>, Reinette Chatre <reinette.chatre@xxxxxxxxx>, Eric Auger <eric.auger@xxxxxxxxxx>, Ye Bin <yebin10@xxxxxxxxxx>, Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>, Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxx>, Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>, Kai Vehmanen <kai.vehmanen@xxxxxxxxxxxxxxx>, Peter Ujfalusi <peter.ujfalusi@xxxxxxxxxxxxxxx>, Rui Salvaterra <rsalvaterra@xxxxxxxxx>, Marc Zyngier <maz@xxxxxxxxxx>, linux-ide@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, linux-input@xxxxxxxxxxxxxxx, netdev@xxxxxxxxxxxxxxx, linux-wireless@xxxxxxxxxxxxxxx, ntb@xxxxxxxxxxxxxxx, linux-pci@xxxxxxxxxxxxxxx, linux-staging@xxxxxxxxxxxxxxx, kvm@xxxxxxxxxxxxxxx, xen-devel@xxxxxxxxxxxxxxxxxxxx, linux-sound@xxxxxxxxxxxxxxx
- Delivery-date: Fri, 11 Oct 2024 12:16:33 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On Thu, 2024-10-10 at 17:40 +0300, Andy Shevchenko wrote:
> On Wed, Oct 09, 2024 at 10:35:07AM +0200, Philipp Stanner wrote:
> > pci_intx() is a hybrid function which sometimes performs devres
> > operations, depending on whether pcim_enable_device() has been used
> > to
> > enable the pci_dev. This sometimes-managed nature of the function
> > is
> > problematic. Notably, it causes the function to allocate under some
> > circumstances which makes it unusable from interrupt context.
> >
> > To, ultimately, remove the hybrid nature from pci_intx(), it is
> > first
> > necessary to provide an always-managed and a never-managed version
> > of that function. Then, all callers of pci_intx() can be ported to
> > the
> > version they need, depending whether they use pci_enable_device()
> > or
> > pcim_enable_device().
> >
> > An always-managed function exists, namely pcim_intx(), for which
> > __pcim_intx(), a never-managed version of pci_intx() had been
> > implemented.
>
> > Make __pcim_intx() a public function under the name
> > pci_intx_unmanaged(). Make pcim_intx() a public function.
>
> To avoid an additional churn we can make just completely new APIs,
> namely:
> pcim_int_x()
> pci_int_x()
>
> You won't need all dirty dances with double underscored function
> naming and
> renaming.
Ähm.. I can't follow. The new version doesn't use double underscores
anymore. __pcim_intx() is being removed, effectively.
After this series, we'd end up with a clean:
pci_intx() <-> pcim_intx()
just as in the other PCI APIs.
>
>
> ...
>
> > + pci_read_config_word(pdev, PCI_COMMAND, &pci_command);
> > +
> > + if (enable)
> > + new = pci_command & ~PCI_COMMAND_INTX_DISABLE;
> > + else
> > + new = pci_command | PCI_COMMAND_INTX_DISABLE;
> > +
> > + if (new != pci_command)
>
> I would use positive conditionals as easy to read (yes, a couple of
> lines
> longer, but also a win is the indentation and avoiding an additional
> churn in
> the future in case we need to add something in this branch.
I can't follow. You mean:
if (new == pci_command)
return;
?
That's exactly the same level of indentation. Plus, I just copied the
code.
>
> > + pci_write_config_word(pdev, PCI_COMMAND, new);
>
> ...
>
> Otherwise I'm for the idea in general.
\o/
>
|