camcontrol rescan all fails if there is no bus 0

[Scott Long]

On Oct 31, 2010, at 8:10 AM, Ed Maste wrote:

> On Tue, Oct 26, 2010 at 10:41:11AM -0600, Scott Long wrote:
> 
>> Ok, I guess I need to see if CAM_XPT_PATH_ID can get returned from the
>> devmatch.
> 
> Is that not handled by this code that parses the returned XPT_DEV_MATCH
> results in in reset_or_rescan_bus:
> 
>    for (i = 0; i < matchccb.cdm.num_matches; i++) {
>            struct bus_match_result *bus_result;
> 
> ...
> 
>            bus_result = &matchccb.cdm.matches[i].result.bus_result;
> 
>            /*
>             * We don't want to rescan or reset the xpt bus.
>             * See above.
>             */
>            if ((int)bus_result->path_id == -1)
>                    continue;
> 
> That is, we do the actual rescan only on legitimate busses after the
> XPT_DEV_MATCH ioctl returns.
> 
>> What happens with this patch if you run it with no real buses
>> registered (i.e. cam module present, but no SIMs present)?
> 
> From the user's perspective, with the stock camcontrol and no
> registered busses I get: 
> 
> [root at edlaptop ~]# camcontrol rescan all
> camcontrol: CAMIOCOMMAND ioctl failed: Invalid argument
> 
> With the patch:
> 
> [root at edlaptop ~]# ./camcontrol rescan all
> [root at edlaptop ~]#
> 
> And then with a umass device attached:
> 
> [root at edlaptop ~]# ./camcontrol rescan all
> Re-scan of bus 0 was successful
> 
> -Ed

That all looks entirely reasonable.  Thanks for researching it.

Scott