> -----Original Message----- > From: Nicholas Mc Guire <der.h...@hofr.at> > Sent: Thursday, January 10, 2019 8:44 PM > To: Leo Li <leoyang...@nxp.com> > Cc: Scott Wood <o...@buserror.net>; linuxppc-dev <linuxppc- > d...@lists.ozlabs.org>; lkml <linux-kernel@vger.kernel.org>; moderated > list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE <linux-arm- > ker...@lists.infradead.org>; Nicholas Mc Guire <hof...@osadl.org> > Subject: Re: [PATCH] soc: fsl: guts: us devm_kstrdup_const() for RO data > > On Thu, Jan 10, 2019 at 01:43:01PM -0600, Li Yang wrote: > > On Sat, Dec 22, 2018 at 2:02 AM Nicholas Mc Guire <der.h...@hofr.at> > wrote: > > > > > > On Fri, Dec 21, 2018 at 08:29:56PM -0600, Scott Wood wrote: > > > > On Fri, 2018-12-07 at 09:22 +0100, Nicholas Mc Guire wrote: > > > > > devm_kstrdup() may return NULL if internal allocation failed, > > > > > but as machine is from the device tree, and thus RO, > > > > > devm_kstrdup_const() can be used here, which will only copy the > reference. > > > > > > > > Is it really going to only copy the reference? That would require > > > > that > > > > is_kernel_rodata(machine) be true, which it shouldn't be since > > > > it's not part of the kernel image. > > > > > > > I had tried to figure out what is RO and what not but was not able > > > to determine that - from the discussion it seemed that the > > > assumption of RO is correct though I did not ask if it would satisfy > > > is_kernel_rodata() so that explains the incorrect assertion. > > > see > > > > https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fl > > > > kml.org%2Flkml%2F2018%2F12%2F6%2F42&data=02%7C01%7Cleoyang.l > i%40 > > > > nxp.com%7Cf72d70a65d1b47f6883808d6776e9d58%7C686ea1d3bc2b4c6fa92c > d99 > > > > c5c301635%7C0%7C1%7C636827714307963102&sdata=xnaO0Y7q%2Byad > Yv8sF > > > VPFtkfllgnwpEIkkTIgw0K%2Fovg%3D&reserved=0 > > > So then the only option is to check the return and cleanup on > > > allocation failure as the orriginal patch proposed. > > > > Thanks for the good discussion. I will drop the previous patch. But > > would it also be good to just have "soc_dev_attr.machine = machine" > > directly? > > > I think that the intent is to switch to managed devm API so that the cleanup > is > handled properly currently you would get "machine" from > of_property_read_string_index > -> of_property_read_string_helper > -> of_find_property > which does not do any allocation - so there would actually not be anything to > cleanup here - don´t see why your solution would not be suitable given the > current API. the only advantage of the devm_kstrdup() is that underlying > APIs internal changes would have no effect. Thanks. I will sent out a new version. Regards, Leo
