Re: x86/paravirt: Use a single ops structure

From: Marc Dionne
Date: Mon Oct 29 2018 - 08:58:46 EST

On Tue, Oct 23, 2018 at 2:37 PM Linux Kernel Mailing List
<linux-kernel@xxxxxxxxxxxxxxx> wrote:
> Commit: 5c83511bdb9832c86be20fb86b783356e2f58062
> Parent: 27876f3882fdd4acb3d3614a0133ecdc777fc292
> Refname: refs/heads/master
> Web:
> Author: Juergen Gross <jgross@xxxxxxxx>
> AuthorDate: Tue Aug 28 09:40:19 2018 +0200
> Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> CommitDate: Mon Sep 3 16:50:35 2018 +0200
> x86/paravirt: Use a single ops structure
> Instead of using six globally visible paravirt ops structures combine
> them in a single structure, keeping the original structures as
> sub-structures.
> This avoids the need to assemble struct paravirt_patch_template at
> runtime on the stack each time apply_paravirt() is being called (i.e.
> when loading a module).

The above commit replaces pv_lock_ops, which was EXPORT_SYMBOL, with
something that is part of pv_ops, which is EXPORT_SYMBOL_GPL. When
CONFIG_PARAVIRT_SPINLOCKS is set, this has the side effect of making
spin_lock() unusable by out of tree modules, which will likely be an
issue for many, if not most of them.