On Fri, Jan 11, 2013 at 03:02:02PM +0000, Grant Likely wrote: > On Thu, 3 Jan 2013 19:04:55 +0300, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote: > > On Sat, Dec 22, 2012 at 09:56:20AM +0000, Grant Likely wrote: > > > On Wed, 19 Dec 2012 19:39:14 +0300, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote: > > > > On Wed, Dec 19, 2012 at 03:11:54PM +0000, Grant Likely wrote: > > > > > On Tue, 11 Dec 2012 16:36:27 -0800 (PST), Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx> wrote: > > > > > > > > > > > > Hi > > > > > > > > > > > > > According to its documentation, clk_get() returns a "valid IS_ERR() condition > > > > > > > containing errno", so we should call IS_ERR() rather than a NULL check. > > > > > > > > > > > > > > Signed-off-by: Cyril Roelandt <tipecaml@xxxxxxxxx> > > > > > > > > > > > > Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx> > > > > > > > > > > Applied, thanks. > > > > > > > > In another thread, we were just talking about who clk_get() can > > > > return a NULL if !CONFIG_HAVE_CLK. That might change to match the > > > > documentation later... Not sure. > > > > > > So what is the solution here? Will the dummy clk_get() be changed, or is > > > there more work needed on the drivers? > > > > > > > This driver can't function without a clk. It should select that at > > build time instead of testing for it at probe. Just checking for > > IS_ERR() will NOT cause a NULL dereference so the patch is ok in > > that respect. I'm not sure if this can be build without > > CONFIG_HAVE_CLK. > > Your suggestion is to make this driver depend on CONFIG_HAVE_CLK? I'm > fine with that, but it doesn't sort out the core infrastructure question > about whether it is valid for the empty clk_get() to return NULL. Nor is > it a particularly sustainable solution (ie. if a large number of drivers > want to do the same thing). > We've spread this conversation out across several different threads. http://lists.infradead.org/pipermail/linux-arm-kernel/2013-January/139186.html Basically, drivers should use accessor functions which handle NULL pointers instead of dereferencing the pointer directly. regards, dan carpenter -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
