On 11. 08. 23, 12:26, Ilpo Järvinen wrote:
On Thu, 10 Aug 2023, Jiri Slaby (SUSE) wrote:
Currently, the tty layer ops and functions use various types for same
things:
* characters and flags: unsigned char, char are used on a random basis,
* counts: int, unsigned int, size_t are used, again more-or-less
randomly.
This makes it rather hard to remember where each type is required and it
also makes the code harder to follow. Also the code has to do min_t() on
many places simply because the variables hold the same kind of data, but
of different type.
This is the first part of the series to unify the types:
* make characters and flags 'u8'. This is what the hardware expects and
what feeds the tty layer with. Since we compile with -funsigned-char,
char and unsigned char are the same types on all platforms. So there
is no actual change in type.
* make sizes/counts 'size_t'. This is what comes from the VFS layer and
some tty functions already operate on this. So instead of using
"shorter" (in term of bytes on 64bit) unsigned int, stick to size_t
and promote it to most places.
More cleanup and spreading will be done in tty_buffer, n_tty, and
likely other places later.
Patches 1-8 are cleanups only. The rest (the real switch) depends on
those.
Yeah, very much needed change and step into the right direction!
It's a bit tedious to review all this and comment a particular subchange
but e.g. n_tty_receive_buf_common() still seems to still have int count
which I think fall into the same call chain about size/count (probably
most related change is #15). Note though that it also has room which I
think can actually become negative so it might not be as straightforward
search and replace like some other parts are.
tl;dr
https://git.kernel.org/pub/scm/linux/kernel/git/jirislaby/linux.git/commit/?h=devel&id=9abb593df5a9b9b72d13438f1862ca67936f6b66
----
Yes, sorry, my bad -- I forgot to elaborate on why this is "part I." and
what is going to be part II., III., ...
So yeah, I have more in my queue which is growing a lot. I had to cut it
at some point as I was losing myself in all the changes already. So I
flushed this "part I.". It is only a minimalistic change in the core and
necessary changes in drivers' hooks. Parts II. and on will spread this
more, of course. Ideally, to every single loop in every driver ;) (in
long-term).
I still have a bunch of changes for tty_buffer and n_tty in my queue. As
soon as I rebase on the today's -next which is already supposed to
contain this part I., I will send part II. with these changes. I could
have merged those II. changes to some earlier I. patches. At first, I
actually did try, but the patches were growing with more and more
dependencies, so I stopped this approach. Instead, I separated the
changes per the core/ldisc/drivers. The parts are self-contained,
despite it might look like the changes are incomplete (i.e. not
everything is changed everywhere). After all, I wanted to avoid one
hundred+ patches series.
thanks,
--
js
suse labs
