On Wed, Oct 07, 2020 at 03:10:17PM -0500, Tony Asleson wrote: > On 10/1/20 6:48 AM, Greg Kroah-Hartman wrote: > > On Wed, Sep 30, 2020 at 09:35:52AM -0500, Tony Asleson wrote: > >> On 9/30/20 2:38 AM, Greg Kroah-Hartman wrote: > >>> On Tue, Sep 29, 2020 at 05:04:32PM -0500, Tony Asleson wrote: > >>>> I'm trying to figure out a way to positively identify which storage > >>>> device an error belongs to over time. > >>> > >>> "over time" is not the kernel's responsibility. > >>> > >>> This comes up every 5 years or so. The kernel provides you, at runtime, > >>> a mapping between a hardware device and a "logical" device. It can > >>> provide information to userspace about this mapping, but once that > >>> device goes away, the kernel is free to reuse that logical device again. > >>> > >>> If you want to track what logical devices match up to what physical > >>> device, then do it in userspace, by parsing the log files. > >> > >> I don't understand why people think it's acceptable to ask user space to > >> parse text that is subject to change. > > > > What text is changing? The format of of the prefix of dev_*() is well > > known and has been stable for 15+ years now, right? What is difficult > > in parsing it? > > Many of the storage layer messages are using printk, not dev_printk. Ok, then stop right there. Fix that up. Don't try to route around the standard way of displaying log messages by creating a totally different way of doing things. Just use the dev_*() calls, and all will be fine. Kernel log messages are not "ABI" in that they have to be preserved in any specific way, so adding a prefix to them as dev_*() does, will be fine. thanks, greg k-h
