Hi David, On 08/24/22 at 08:16am, David Laight wrote: ...... > > >>>> Le 20/08/2022 à 02:31, Baoquan He a écrit : > > >>>>> In some architectures, there are ARCH specifici io address mapping > > >>>>> handling when calling ioremap() or ioremap_prot(), e.g, arc, ia64, > > >>>>> openrisc, s390, sh. > > >>>>> > > >>>>> In oder to convert them to take GENERIC_IOREMAP method, we need change > > >>>>> the return value of hook ioremap_allowed() and iounmap_allowed(). > > >>>>> Meanwhile, rename them to arch_ioremap() and arch_iounmap() to reflect > > >>>>> their current behaviour. > > >>> > > >>> Thanks for reviewing. > > >>> > > >>>> > > >>>> Please don't just say you need to change the return value. Explain why. > > >>> > > >>> The 1st paragraph and the sentence 'In oder to convert them to take > > >>> GENERIC_IOREMAP method' tell the reason, no? > > >> > > >> What I would like to read is _why_ you need to change the return value > > >> in order to convert to GENERIC_IOREMAP > > > > > > I rephrase the log as below, it's OK to you? Or please help check and > > > tell what I need to improve to better explain the reason. > > > > > > ==== > > > The current io[re|un]map_allowed() hooks are used to check if the > > > io[re|un]map() actions are qualified to proceed when taking > > > GENERIC_IOREMAP way to do ioremap()/iounmap(). Otherwise io[re|un]map() > > > will return NULL. > > > > > > On some architectures like arc, ia64, openris, s390, sh, there are > > > ARCH specific io address mapping to translate the passed in physical > > > address to io address when calling ioremap(). In order to convert > > > these architectures to take GENERIC_IOREMAP way to ioremap(), we need > > > change the return value of hook ioremap_allowed() and iounmap_allowed(). > > > With the change, we can move the architecture specific io address > > > mapping into ioremap_allowed() hook, and give the mapped io address > > > out to let ioremap_prot() return it. While at it, rename the hooks to > > > arch_ioremap() and arch_iounmap() to reflect their new behaviour. > > > ==== > > > > > > > That looks more in line with the type of explanation I foresee in the > > commit message, thanks. > > I think you also need to summarise the change itself. > If the success/fail return actually changes then you really > need to change something so the compiler errors unchanged code. > Otherwise it is a complete recipe for disaster. Thanks for looking into this and sorry for late response. I am not sure if I follow you. In this patch, I just rename the old ioremap_allowed() to arch_ioremap(), and change its return value. Except of arm64 which has taken GENERIC_IOREMAP way to provide ioremap_allowed(), no other ARCHes are affected yet. This is what have been changed. Could you be more specific what I should add? Or are you suggesting words like below sentences need be added to patch log? If the success/fail return actually changes then you really need to change something so the compiler errors unchanged code. Otherwise it is a complete recipe for disaster. Thanks Baoquan
