Re: [RFC][PATCH 01/12 v3] x86/kvm/tracing: Use helper function trace_seq_buffer_ptr()

Steven Rostedt
2014-11-04T19:09:58Z

On Tue, 4 Nov 2014 17:17:08 +0000
"Rustad, Mark D" <mark.d.rustad@intel.com> wrote:

> On Nov 4, 2014, at 7:52 AM, Steven Rostedt <rostedt@goodmis.org> wrote:
>
> > From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
> >
> > To allow for the restructiong of the trace_seq code, we need users
> > of it to use the helper functions instead of accessing the internals
> > of the trace_seq structure itself.
> >
> > Cc: Mark Rustad <mark.d.rustad@intel.com>
> > Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
> > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> > ---
> > arch/x86/kvm/mmutrace.h | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h
> > index 5aaf35641768..ce463a9cc8fb 100644
> > --- a/arch/x86/kvm/mmutrace.h
> > +++ b/arch/x86/kvm/mmutrace.h
> > @@ -22,7 +22,7 @@
> > __entry->unsync = sp->unsync;
> >
> > #define KVM_MMU_PAGE_PRINTK() ({ \
> > - const u32 saved_len = p->len; \
> > + const char *saved_ptr = trace_seq_buffer_ptr(p); \
>
> I think the above should not be a const char *, because the location pointed to is surely being changed. It should either be a char * or a char * const.

Ah right. It should be 'char * const'.

Thanks, I'll update it.

-- Steve

>
> > static const char *access_str[] = { \
> > "---", "--x", "w--", "w-x", "-u-", "-ux", "wu-", "wux" \
> > }; \
> > @@ -41,7 +41,7 @@
> > role.nxe ? "" : "!", \
> > __entry->root_count, \
> > __entry->unsync ? "unsync" : "sync", 0); \
> > - p->buffer + saved_len; \
> > + saved_ptr; \
> > })
> >
> > #define kvm_mmu_trace_pferr_flags \
> > --
> > 2.1.1
>