Re: [PATCH] x86/pci: Annotate 'pci_root_ops' with __ro_after_init

From: Thomas Gleixner <tglx@linutronix.de>
To: Zubin Mithra <zsm@chromium.org>
Cc: mingo@redhat.com, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-pci@vger.kernel.org, groeck@chromium.org,
	Kees Cook <keescook@chromium.org>,
	Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: [PATCH] x86/pci: Annotate 'pci_root_ops' with __ro_after_init
Date: Mon, 5 Nov 2018 22:38:25 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.21.1811052232020.1659@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20181105201735.72026-1-zsm@chromium.org>

On Mon, 5 Nov 2018, Zubin Mithra wrote:

Cc+: Bjorn

> When CONFIG_X86_INTEL_MID is set pci_root_ops is written to inside
> intel_mid_pci_init(which is marked __init) and not modified after. This
> makes pci_root_ops a suitable candidate for annotating as
> __ro_after_init.

This is confusing. What about CONFIG_X86_INTEL_MID=n?

What you want to say is:

 pci_root_ops is only modified from intel_mid_pci_init() which is a init
 function, so it can be made __ro_after_init.

or something like this. Hmm?

Other than the nitpick above:

      Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

> Signed-off-by: Zubin Mithra <zsm@chromium.org>
> ---
>  arch/x86/pci/common.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
> index d4ec117c1142..204ee80cfa63 100644
> --- a/arch/x86/pci/common.c
> +++ b/arch/x86/pci/common.c
> @@ -67,7 +67,7 @@ static int pci_write(struct pci_bus *bus, unsigned int devfn, int where, int siz
>  				  devfn, where, size, value);
>  }
>  
> -struct pci_ops pci_root_ops = {
> +struct pci_ops pci_root_ops __ro_after_init = {
>  	.read = pci_read,
>  	.write = pci_write,
>  };
> -- 
> 2.19.1.930.g4563a0d9d0-goog
> 
> 