Re: [RFC PATCH 1/5] IB/core: Add Core Capability flags to ib_device

[Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

[-- Attachment #1: Type: text/plain, Size: 1350 bytes --]

On Mon, 2015-05-04 at 16:42 +0000, Hefty, Sean wrote:

> >  struct ib_port_attr {
> >  	enum ib_port_state	state;
> >  	enum ib_mtu		max_mtu;
> >  	enum ib_mtu		active_mtu;
> >  	int			gid_tbl_len;
> > +	u64                     core_cap_flags;
> >  	u32			port_cap_flags;
> >  	u32			max_msg_sz;
> >  	u32			bad_pkey_cntr;
> > @@ -1684,6 +1705,7 @@ struct ib_device {
> >  	u32			     local_dma_lkey;
> >  	u8                           node_type;
> >  	u8                           phys_port_cnt;
> > +	u64                         *core_cap_flags; /* Per port core
> > capability flags */
> 
> Why are the core_cap_flags duplicated in the struct and in port attributes?

Because the per port ib_port_attr struct is not visible to the core
code, it must call ib_query_port each time it wants to see it.  In order
to make the helpers avoid a call, you have to stash the cap_flags into
the ib_device struct.  In the past, the only thing there was the
node_type, and it was per device and not per node.  In order to make all
of this work and not require calls into the driver all the time, that
has to change to a per-port array.  Eventually we could get rid of the
node_type element once everything is in place.


-- 
Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
              GPG KeyID: 0E572FDD



[-- Attachment #2: This is a digitally signed message part --]
[-- Type: application/pgp-signature, Size: 819 bytes --]