On Wed, Oct 07, 2020 at 03:10:17PM -0500, Tony Asleson wrote:

On 10/1/20 6:48 AM, Greg Kroah-Hartman wrote:

quoted

On Wed, Sep 30, 2020 at 09:35:52AM -0500, Tony Asleson wrote:

quoted

On 9/30/20 2:38 AM, Greg Kroah-Hartman wrote:

quoted

On Tue, Sep 29, 2020 at 05:04:32PM -0500, Tony Asleson wrote:

quoted

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