Re: [PATCH 2/8] zram: use idr instead of `zram_devices' array

Sergey Senozhatsky
2015-03-04T00:21:11Z

On (03/03/15 14:01), Andrew Morton wrote:
> > This patch makes some preparations for dynamic device ADD/REMOVE functionality
> > via /dev/zram-control interface.
> >
> > Remove `zram_devices' array and switch to id-to-pointer translation (idr).
> > idr doesn't bloat zram struct with additional members, f.e. list_head, yet
> > still provides ability to match the device_id with the device pointer.
> > No user-space visible changes.
> >
> > ...
> >
> > +static DEFINE_IDR(zram_index_idr);
>
> There is no locking protecting this idr?
>

correct. there is no concurrent idr index modification at this point.
add/remove functionality and concurrent idr modification will be intoriduced
in the patch 0005 zram add dynamic device add remove functionality (along
with `static DEFINE_MUTEX(zram_index_mutex)' idr protection).

-ss