Messages in this thread | | | Date | Thu, 15 Apr 2021 16:53:48 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH 00/13] tty.h cleanups |
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On Thu, Apr 15, 2021 at 04:14:33PM +0200, Johan Hovold wrote: > On Thu, Apr 15, 2021 at 10:21:54AM +0200, Greg Kroah-Hartman wrote: > > On Fri, Apr 09, 2021 at 09:32:45AM +0200, Johan Hovold wrote: > > > On Thu, Apr 08, 2021 at 08:01:08PM +0200, Greg Kroah-Hartman wrote: > > > > On Thu, Apr 08, 2021 at 04:25:22PM +0200, Johan Hovold wrote: > > > > > On Thu, Apr 08, 2021 at 02:51:21PM +0200, Greg Kroah-Hartman wrote: > > > > > > Turns out there is a lot of tty-internal stuff in include/linux/tty.h > > > > > > that do not belong there. Create a internal-to-the-tty-layer .h file > > > > > > for these types of things and move function prototypes to it instead of > > > > > > being in the system-wide header file. > > > > > > > > > > > > Along the way clean up the use of some old tty-only debugging macros and > > > > > > use the in-kernel dev_*() calls instead. > > > > > > > > > > I'm afraid that's not a good idea since not all ttys have a > > > > > corresponding class device. Notable exception include pseudo terminals > > > > > and serdev. > > > > > > > > > > While dev_printk() can handle a NULL device argument without crashing, > > > > > we'll actually lose log information by removing the tty printk helpers. > > > > > > > > I think the same info will be printed here as before, just some NULL > > > > information at the beginning, right? And the benifits overall (for real > > > > tty devices), should outweigh the few devices that do not have this > > > > information. > > > > > > No, you'll only be losing information (tty driver and tty name). Here's > > > a pty example, where the first line in each pair use dev_info() and the > > > second tty_info(): > > > > > > [ 10.235331] (NULL device *): tty_get_device > > > [ 10.235441] ptm ptm0: tty_get_device > > > > > > [ 10.235586] (NULL device *): tty_get_device > > > [ 10.235674] pts pts0: tty_get_device > > > > > > and similar for serdev, which is becoming more and more common. > > > > Ok, good point, I'll go apply only the first 2 patches in this series > > (moving the macros out of tty.h and removing the unused one) and then > > will redo this set of patches again. > > Perhaps no harm in leaving the tty_info() on in there for consistency. > We have users of the _ratelimited() flavour of it (even if there's no > dependency).
I dropped it, no need to keep around unused macros :)
> > I think a better tty_msg() macro is warrented so that we can provide > > dev_*() output if we have a device, otherwise fall back to the old > > style to preserve functionality. > > Possibly, but the dev_printk() for the tty class devices wouldn't > provide any more info than what's already there (i.e. driver name + tty > name). > > (And associating ttys with other devices and drivers (e.g. a serdev > client and its driver) might not be what we want since you lose the > connection to the underlying tty driver.)
Yeah, I messed with this for a bit today and I think I'm just going to give up and leave it as-is for now...
thanks,
greg k-h
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