Hi Marek,
On Wed, Aug 01, 2012 at 04:31:04AM +0200, Marek Vasut wrote:
> Dear Guenter Roeck,
>
> [...]
>
> > > +static int __devexit mxs_spi_remove(struct platform_device *pdev)
> > > +{
> > > + struct spi_master *host;
> > > + struct mxs_spi *spi;
> > > + struct mxs_ssp *ssp;
> > > +
> > > + host = platform_get_drvdata(pdev);
> > > + spi = spi_master_get_devdata(host);
> > > + ssp = &spi->ssp;
> > > +
> > > + spi_unregister_master(host);
> > > +
> > > + platform_set_drvdata(pdev, NULL);
> > > +
> > > + clk_disable_unprepare(ssp->clk);
> > > +
> > > + spi_master_put(host);
> > > + kfree(host);
> > > +
> >
> > Is the kfree() here and in the probe function really necessary ?
>
> It certainly would seem that way.
>
> > Couple of reasons for asking: No other SPI master driver calls it in the
> > remove function (unless I missed it), most drivers don't call it in the
> > probe function error path, and if I call it in the remove function in a
> > SPI master driver I am working on, and load/unload the module several
> > times in a row, I get a nasty kernel crash.
>
> It seems the spi_master class takes care of that kfree() in
> spi.c:spi_master_release() . Good catch, thanks!
>
Given that, and assuming that spi_master_put() results in the call to
spi_master_release() for both the error case in the probe function and for
the release function, I take it that the kfree() is not needed at all,
and that the documentation for spi_alloc_master() is wrong. Does that sound
reasonable ?
Thanks,
Guenter
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