From: Marc Zyngier <maz@kernel.org>
To: Barry Song <21cnbao@gmail.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Jonathan.Cameron@huawei.com, bilbao@vt.edu,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
leon@kernel.org, LKML <linux-kernel@vger.kernel.org>,
linux-pci@vger.kernel.org, Linuxarm <linuxarm@huawei.com>,
luzmaximilian@gmail.com, mchehab+huawei@kernel.org,
schnelle@linux.ibm.com, Barry Song <song.bao.hua@hisilicon.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v2 1/2] PCI/MSI: Fix the confusing IRQ sysfs ABI for MSI-X
Date: Mon, 23 Aug 2021 11:33:15 +0100 [thread overview]
Message-ID: <878s0sqwlw.wl-maz@kernel.org> (raw)
In-Reply-To: <CAGsJ_4w35+mRE_qp117HhNOaHeUN1cO6GGPW36qtjaX6wUcQNA@mail.gmail.com>
On Sat, 21 Aug 2021 23:41:17 +0100,
Barry Song <21cnbao@gmail.com> wrote:
[...]
> > So probably we should set this ABI invisible when devices are using
> > MSI or MSI-X?
>
> i mean something like the below,
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 5d63df7..1323841 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -26,6 +26,7 @@
> #include <linux/slab.h>
> #include <linux/vgaarb.h>
> #include <linux/pm_runtime.h>
> +#include <linux/msi.h>
> #include <linux/of.h>
> #include "pci.h"
>
> @@ -1437,6 +1438,16 @@ static umode_t pci_dev_attrs_are_visible(struct
> kobject *kobj,
> if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
> return 0;
>
> +#ifdef CONFIG_PCI_MSI
> + /*
> + * if devices are MSI and MSI-X, IRQ sysfs ABI is meaningless
> + * and broken
> + */
> + if (a == &dev_attr_irq.attr)
> + if (first_pci_msi_entry(pdev))
> + return 0;
> +#endif
> +
> return a->mode;
> }
I don't think you can break what we have today. Whatever change we
make to the kernel internals, the userspace view must stay unchanged.
M.
--
Without deviation from the norm, progress is not possible.
next prev parent reply other threads:[~2021-08-23 10:33 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-20 22:37 [PATCH v2 0/2] PCI/MSI: Clarify the IRQ sysfs ABI for PCI devices Barry Song
2021-08-20 22:37 ` [PATCH v2 1/2] PCI/MSI: Fix the confusing IRQ sysfs ABI for MSI-X Barry Song
2021-08-20 23:33 ` Bjorn Helgaas
2021-08-21 10:42 ` Marc Zyngier
2021-08-21 22:14 ` Barry Song
2021-08-21 22:41 ` Barry Song
2021-08-23 10:33 ` Marc Zyngier [this message]
2021-08-24 19:25 ` Bjorn Helgaas
2021-08-23 10:30 ` Marc Zyngier
2021-08-23 11:03 ` Barry Song
2021-08-23 11:28 ` Marc Zyngier
2021-08-23 22:46 ` Barry Song
2021-08-24 19:34 ` Bjorn Helgaas
2021-08-25 9:45 ` Marc Zyngier
2021-08-24 20:51 ` Barry Song
2021-08-24 21:29 ` Barry Song
2021-08-25 10:24 ` Marc Zyngier
2021-08-24 22:51 ` Barry Song
2021-08-20 22:37 ` [PATCH v2 2/2] Documentation: ABI: sysfs-bus-pci: Add description for IRQ entry Barry Song
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