[PATCH -next] spi: s3c64xx: fix reference leak to master in s3c64xx_spi_remove()

Andi Shyti
2016-07-13T08:34:13Z

Hi Wei,

> >> Once a spi_master_get() call succeeds, we need an additional
> >> spi_master_put() call to free the memory, otherwise we will
> >> leak a reference to master. Fix by removing the unnecessary
> >> spi_master_get() call.
> >>
> >> Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
> >
> >The patch doesn't have anything wrong, but what you write in the
> >description is not what you are doing in the patch.
> >
> >There is no memory allocated in spi_master_get and nothing leaks.
> >Besides master's resources are managed, so that there would
> >not be any need to call spi_master_put().
> >
> >spi_master_put() has been, indeed, removed in this commit:
> >91800f0e90050a4db4c77e940796f501e02af8be.
> >
>
> master allocated in spi_alloc_master() need device reference count to zero
> to be freed.
>
> The call sequence spi_alloc_master/spi_register_master/spi_unregister_master
> is complete; it reduces the device reference count to zero, which results in
> device memory being freed.
>
> In commit 91800f0e90050a4db4c77e940796f501e02af8be,
> devm_spi_register_master() equal to spi_register_master() and auto call
> spi_unregister_master() when remove. But remove spi_master_put()
> will cause the device reference count left no zero, since spi_master_get()
> is callled at the begin of remove function already.
>
> So I think we should either remove the spi_master_get() or add spi_master_put()
> before return from remove function.

Yes, you are right, I missed this part :)

Thanks,
Andi