Re: [PATCH 1/2]pstore: Move timestamp collection code to common pstore place

[Ankit Kumar]

Hi Kees,

Thank you so much for your response.



On Tuesday 23 May 2017 05:07 AM, Kees Cook wrote:
> On Mon, May 22, 2017 at 3:20 AM, Ankit Kumar <ankit@xxxxxxxxxxxxxxxxxx> wrote:
> > Current pstore code(ram.c) gets dump timestamp and make it part of header.
> > Different diffent architecture uses different header format and hence it
> > won't be good idea to make ramoops_write_kmsg_hdr/ramoops_read_kmsg_hdr
> > part of generic pstore code.
> >
> > ramoops_write_kmsg_hdr calls __getnstimeofday to get timestamp and also
> > takes care of condition if timekeeping has not resumed.
> >
> > This patch moves code for retrieving timestamp to common place and hence
> > can be used by other functions as well.
> Ah! Heh, funny, I had just done a version of this while working on EFI
> pstore fixes. Here's what I did instead:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?h=pstore/fixes&id=ea209b760f104daf0cf62953090b66c5628b0842
>
> This makes it so the time field is prepopulated for all backend
> writes, which should simplify things (no need to have the backends
> call out).


Above mentioned patch moves code to common place and also simplifies things.
I agree, My patch is not required anymore.

Thank you;

~Ankit




> -Kees
>
> > Signed-off-by: Ankit Kumar <ankit@xxxxxxxxxxxxxxxxxx>
> > ---
> >   fs/pstore/internal.h |  1 +
> >   fs/pstore/platform.c | 13 +++++++++++++
> >   fs/pstore/ram.c      |  9 ++++-----
> >   3 files changed, 18 insertions(+), 5 deletions(-)
> >
> > diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h
> > index c416e65..339dcdc 100644
> > --- a/fs/pstore/internal.h
> > +++ b/fs/pstore/internal.h
> > @@ -22,6 +22,7 @@ static inline void pstore_unregister_pmsg(void) {}
> >   #endif
> >
> >   extern struct pstore_info *psinfo;
> > +void pstore_get_timestamp(struct timespec *timestamp);
> >
> >   extern void    pstore_set_kmsg_bytes(int);
> >   extern void    pstore_get_records(int);
> > diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
> > index d468eec..5cb25b0 100644
> > --- a/fs/pstore/platform.c
> > +++ b/fs/pstore/platform.c
> > @@ -474,6 +474,19 @@ static size_t copy_kmsg_to_buffer(int hsize, size_t len)
> >          return total_len;
> >   }
> >
> > +void pstore_get_timestamp(struct timespec *timestamp)
> > +{
> > +       if (!timestamp)
> > +               return;
> > +
> > +       /* Report zeroed timestamp if called before timekeeping has resumed. */
> > +       if (__getnstimeofday(timestamp)) {
> > +               timestamp->tv_sec = 0;
> > +               timestamp->tv_nsec = 0;
> > +       }
> > +}
> > +EXPORT_SYMBOL_GPL(pstore_get_timestamp);
> > +
> >   /*
> >    * callback from kmsg_dump. (s2,l2) has the most recently
> >    * written bytes, older bytes are in (s1,l1). Save as much
> > diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
> > index 5cb022c..e39297d 100644
> > --- a/fs/pstore/ram.c
> > +++ b/fs/pstore/ram.c
> > @@ -37,6 +37,8 @@
> >   #include <linux/of.h>
> >   #include <linux/of_address.h>
> >
> > +#include "internal.h"
> > +
> >   #define RAMOOPS_KERNMSG_HDR "===="
> >   #define MIN_MEM_SIZE 4096UL
> >
> > @@ -362,11 +364,8 @@ static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
> >          struct timespec timestamp;
> >          size_t len;
> >
> > -       /* Report zeroed timestamp if called before timekeeping has resumed. */
> > -       if (__getnstimeofday(&timestamp)) {
> > -               timestamp.tv_sec = 0;
> > -               timestamp.tv_nsec = 0;
> > -       }
> > +       pstore_get_timestamp(&timestamp);
> > +
> >          hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n",
> >                  (long)timestamp.tv_sec, (long)(timestamp.tv_nsec / 1000),
> >                  compressed ? 'C' : 'D');
> > --
> > 2.7.4