[dm-devel] [PATCH 2/5] libmultipath: change reservation_key to a uint64_t
Benjamin Marzinski
bmarzins at redhat.com
Fri Sep 8 22:55:03 UTC 2017
On Fri, Sep 08, 2017 at 11:09:17PM +0200, Martin Wilck wrote:
> On Fri, 2017-09-08 at 13:45 -0500, Benjamin Marzinski wrote:
> > The reservation key is currently being stored as any array of 8
> > unsigned
> > chars. This is exactly the same in-memory representation as a big
> > endian 64 bit integer. However, the code for dealing with a big
> > endian
> > 64 bit integer is much simpler, so switch to use that instead.
> >
> > Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
> > ---
> > libmpathpersist/mpath_persist.c | 23 +++++++----------------
> > libmultipath/byteorder.h | 36
> > ++++++++++++++++++++++++++++++++++++
> > libmultipath/config.c | 3 ---
> > libmultipath/config.h | 6 ++++--
> > libmultipath/dict.c | 31 ++++---------------------------
> > libmultipath/propsel.c | 6 +++---
> > libmultipath/structs.h | 5 ++++-
> > multipathd/main.c | 23 +++++------------------
> > 8 files changed, 63 insertions(+), 70 deletions(-)
> > create mode 100644 libmultipath/byteorder.h
> >
> >
> > char * prio_name;
> > char * prio_args;
> > - unsigned char * reservation_key;
> > + uint64_t reservation_key; /* stored in big-endian format */
>
> I would prefer if you could encapsulate this into a type that can't be
> implicitly converted to an int, such as
>
> struct res_key {
> uint64_t _v;
> } reservation_key;
>
> together with macros like
>
> #define reskey_to_uint64(r) be64_to_cpu((r)->_v)
> #define set_reskey_from_uint64(r, x) do { (r)->_v = (x); } while (0)
>
> Using be64_to_cpu is all too easily forgotten, which leads to nasty
> bugs.
That's a good idea. I'll resend with a structure instead of a straight
uint64_t.
-Ben
>
> Apart from that, ack.
>
> --
> Dr. Martin Wilck <mwilck at suse.com>, Tel. +49 (0)911 74053 2107
> SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton
> HRB 21284 (AG Nürnberg)
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