From: Leon Romanovsky <leonro@nvidia.com>
To: Keith Busch <kbusch@kernel.org>
Cc: Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Jim Harris <jim.harris@samsung.com>,
Bjorn Helgaas <bhelgaas@google.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Jason Gunthorpe" <jgg@nvidia.com>,
Alex Williamson <alex.williamson@redhat.com>,
"pierre.cregut@orange.com" <pierre.cregut@orange.com>
Subject: Re: [PATCH v2 2/2] pci/iov: fix kobject_uevent() ordering in sriov_enable()
Date: Mon, 12 Feb 2024 17:29:59 +0200 [thread overview]
Message-ID: <20240212152959.GB16050@unreal> (raw)
In-Reply-To: <Zco2pmQWR49V9Imw@kbusch-mbp.mynextlight.net>
On Mon, Feb 12, 2024 at 08:17:58AM -0700, Keith Busch wrote:
> On Fri, Feb 09, 2024 at 07:22:17PM -0800, Kuppuswamy Sathyanarayanan wrote:
> > On 2/9/24 3:52 PM, Jim Harris wrote:
> > > @@ -677,8 +677,8 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
> > > if (rc)
> > > goto err_pcibios;
> > >
> > > - kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
> > > iov->num_VFs = nr_virtfn;
> > > + kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
>
> Since it's accessed unlocked now, I *think* this wants appropriate
> barriers to ensure the order is observed the same on all CPUs. Something
> like 'smp_store_release(&iov->num_VFs, nr_virtfn)' for writing it, and
> use 'smp_load_acquire()' on the read-side.
It is unlocked only for sysfs read. IMHO it is overkill to use stores
for this case.
Thanks
>
prev parent reply other threads:[~2024-02-12 15:30 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20240209235208uscas1p26c658c64cc85711cd3aa6312224164fc@uscas1p2.samsung.com>
2024-02-09 23:52 ` [PATCH v2 0/2] PCI/IOV: sriov_numvfs bug fixes Jim Harris
2024-02-09 23:52 ` [PATCH v2 1/2] PCI/IOV: Revert "PCI/IOV: Serialize sysfs sriov_numvfs reads vs writes" Jim Harris
2024-02-10 3:20 ` Kuppuswamy Sathyanarayanan
2024-02-11 8:48 ` Leon Romanovsky
2024-02-11 19:15 ` Kuppuswamy Sathyanarayanan
2024-02-12 9:31 ` Leon Romanovsky
2024-02-12 20:27 ` Bjorn Helgaas
2024-02-12 22:59 ` Jim Harris
2024-02-13 7:37 ` Leon Romanovsky
2024-02-13 9:40 ` pierre.cregut
2024-02-13 14:59 ` Jason Gunthorpe
2024-02-13 7:34 ` Leon Romanovsky
2024-02-13 15:59 ` Bjorn Helgaas
2024-02-13 17:46 ` Leon Romanovsky
2024-02-13 18:00 ` Kuppuswamy Sathyanarayanan
2024-02-13 19:45 ` Bjorn Helgaas
2024-02-14 7:16 ` Leon Romanovsky
2024-02-14 17:04 ` Jim Harris
2024-02-14 17:50 ` Bjorn Helgaas
2024-02-14 22:55 ` Jim Harris
2024-02-09 23:52 ` [PATCH v2 2/2] pci/iov: fix kobject_uevent() ordering in sriov_enable() Jim Harris
2024-02-10 3:22 ` Kuppuswamy Sathyanarayanan
2024-02-12 15:17 ` Keith Busch
2024-02-12 15:29 ` Leon Romanovsky [this message]
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