On Wed, Aug 01, 2012 at 08:45:19AM +0200, Marek Vasut wrote:
> Dear Guenter Roeck,
>
> > On Wed, Aug 01, 2012 at 08:10:37AM +0200, Marek Vasut wrote:
> > > Dear Shawn Guo,
> > >
> > > > On Tue, Jul 31, 2012 at 10:42:28PM -0700, Guenter Roeck wrote:
> > > > > On Wed, Aug 01, 2012 at 01:58:56PM +0800, Shawn Guo wrote:
> > > > > > On Tue, Jul 31, 2012 at 10:29:47PM -0700, Guenter Roeck wrote:
> > > > > > > Anyone up for writing some patches ? If not, I'll do it.
> > > > > >
> > > > > > Go ahead.
> > > > >
> > > > > Ok, will do. It isn't that simple, actually, since at least some of
> > > > > the drivers also call spi_master_get(), and thus need two calls to
> > > > > spi_master_put() (or a call to spi_master_put and a call to kfree).
> > > >
> > > > Hmm, are you saying that there must be a spi_master_put call matching
> > > > spi_alloc_master? I think we only need to have spi_master_get and
> > > > spi_master_put matched.
> > >
> > > Naw, spi_master_get() does refcounting, spi_alloc_master() doesnt. You
> > > don't need to match spi_alloc_master() with spi_master_put()
> >
> > I must be missing something. Why do almost all spi drivers call it in the
> > error path, even if there is no call to spi_master_get ?
>
> To push the refcounting to 0, to deallocate the device, I'd say ...
>
Guess we are in violent agreement. The sequence would then either be
master = spi_alloc_device();
...
spi_master_put(master);
or
master = spi_alloc_device();
...
kfree(master);
which makes sense to me. Question still is why most drivers neither call kfree()
nor spi_master_put() in the remove function.
Thanks,
Guenter
------------------------------------------------------------------------------
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and
threat landscape has changed and how IT managers can respond. Discussions
will include endpoint security, mobile security and the latest in malware
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
_______________________________________________
spi-devel-general mailing list
spi-devel-general@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/spi-devel-general
