linux-toradex.git/include/linux/tty_ldisc.h, branch v5.16-rc3

tty: make tty_ldisc_ops::hangup return void

2021-09-22T14:59:13+00:00

The documentation says that the return value of tty_ldisc_ops::hangup
hook is ignored. And it really is, so there is no point for its return
type to be int. Switch it to void and all the hooks too.

Cc: Dmitry Torokhov 
Cc: Wolfgang Grandegger 
Cc: Marc Kleine-Budde 
Cc: "David S. Miller" 
Cc: Jakub Kicinski 
Cc: Paul Mackerras 
Cc: Liam Girdwood 
Cc: Mark Brown 
Cc: Jaroslav Kysela 
Cc: Takashi Iwai 
Cc: Peter Ujfalusi 
Acked-by: Dmitry Torokhov 
Acked-by: Mark Brown 
Acked-by: Marc Kleine-Budde 
Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20210914091134.17426-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

tty: remove extern from functions in tty headers

2021-09-22T14:59:13+00:00

After the recent headers cleanup, some function declarations still have
extern before them. It is superfluous (for function declarations), so
remove extern from those which still have it.

This unifies them with the rest of the files.

Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20210914091134.17426-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

tty: remove flags from struct tty_ldisc_ops

2021-09-22T14:59:13+00:00

The last user was apparently removed by commit a352def21a64 (tty: Ldisc
revamp) in 2008. So remove the field completely, the only setter
(n_tty_inherit_ops) and also its only possible value
(LDISC_FLAG_DEFINED).

Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20210914091134.17426-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

tty: include list & lockdep from tty_ldisc.h

2021-07-27T10:12:07+00:00

We use structs list_head and lockdep_map as non-pointers in tty_ldisc.h.
So better have headers defining them explicitly included so that the
structs are always defined. Not only implicitly via random include
chains.

Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20210723103147.18250-5-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

tty: move ldisc prototypes to tty_ldisc.h

2021-07-27T10:12:07+00:00

We already have tty_ldisc.h, so cleanup tty.h a bit by moving out
tty_ldisc-related function prototypes and a variable into tty_ldisc.h.
They are implemented in tty_ldisc.c anyway.

Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20210723103147.18250-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

tty: drop tty_ldisc_ops::refcount

2021-05-13T14:57:17+00:00

The refcount is checked only in tty_unregister_ldisc and EBUSY returned
if it is nonzero. But none of the tty_unregister_ldisc callers act
anyhow if this (or any other) error is returned. So remove
tty_ldisc_ops::refcount completely and make tty_unregister_ldisc return
'void' in the next patches. That means we assume tty_unregister_ldisc is
not called while the ldisc might be in use. That relies on
try_module_get in get_ldops and module_put in put_ldops.

Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20210505091928.22010-18-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

tty: make fp of tty_ldisc_ops::receive_buf{,2} const

2021-05-13T14:57:16+00:00

Char pointer (cp) passed to tty_ldisc_ops::receive_buf{,2} is const.
There is no reason for flag pointer (fp) not to be too. So switch it in
the definition and all uses.

Signed-off-by: Jiri Slaby 
Cc: William Hubbs 
Cc: Chris Brannon 
Cc: Kirk Reiser 
Cc: Samuel Thibault 
Cc: Marcel Holtmann 
Cc: Johan Hedberg 
Cc: Luiz Augusto von Dentz 
Cc: Dmitry Torokhov 
Cc: Arnd Bergmann 
Cc: "David S. Miller" 
Cc: Jakub Kicinski 
Cc: Wolfgang Grandegger 
Cc: Marc Kleine-Budde 
Cc: Andreas Koensgen 
Cc: Paul Mackerras 
Cc: Liam Girdwood 
Cc: Mark Brown 
Cc: Jaroslav Kysela 
Cc: Takashi Iwai 
Cc: Peter Ujfalusi 
Link: https://lore.kernel.org/r/20210505091928.22010-12-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

tty: remove TTY_LDISC_MAGIC

2021-03-10T08:34:06+00:00

First, it is never checked. Second, use of it as a debugging aid is
at least questionable. With the current tools, I don't think anyone used
this kind of thing for debugging purposes for years.

On the top of that, e.g. serdev does not set this field of tty_ldisc_ops
at all.

So get rid of this legacy.

Signed-off-by: Jiri Slaby 
Link: https://lore.kernel.org/r/20210302062214.29627-8-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer

2021-01-21T00:48:47+00:00

The tty line discipline .read() function was passed the final user
pointer destination as an argument, which doesn't match the 'write()'
function, and makes it very inconvenient to do a splice method for
ttys.

This is a conversion to use a kernel buffer instead.

NOTE! It does this by passing the tty line discipline ->read() function
an additional "cookie" to fill in, and an offset into the cookie data.

The line discipline can fill in the cookie data with its own private
information, and then the reader will repeat the read until either the
cookie is cleared or it runs out of data.

The only real user of this is N_HDLC, which can use this to handle big
packets, even if the kernel buffer is smaller than the whole packet.

Cc: Christoph Hellwig 
Cc: Greg Kroah-Hartman 
Cc: Al Viro 
Signed-off-by: Linus Torvalds

change semantics of ldisc ->compat_ioctl()

2018-10-13T04:50:53+00:00

First of all, make it return int.  Returning long when native method
had never allowed that is ridiculous and inconvenient.

More importantly, change the caller; if ldisc ->compat_ioctl() is NULL
or returns -ENOIOCTLCMD, tty_compat_ioctl() will try to feed cmd and
compat_ptr(arg) to ldisc's native ->ioctl().

That simplifies ->compat_ioctl() instances quite a bit - they only
need to deal with ioctls that are neither generic tty ones (those
would get shunted off to tty_ioctl()) nor simple compat pointer ones.

Note that something like TCFLSH won't reach ->compat_ioctl(),
even if ldisc ->ioctl() does handle it - it will be recognized
earlier and passed to tty_ioctl() (and ultimately - ldisc ->ioctl()).

For many ldiscs it means that NULL ->compat_ioctl() does the
right thing.  Those where it won't serve (see e.g. n_r3964.c) are
also easily dealt with - we need to handle the numeric-argument
ioctls (calling the native instance) and, if such would exist,
the ioctls that need layout conversion, etc.

All in-tree ldiscs dealt with.

Signed-off-by: Al Viro