tty: Partially revert the removal of the Cyclades public API

Fix a user API regression introduced with commit f76edd8f7c ("tty:
cyclades, remove this orphan"), which removed a part of the API and
caused compilation errors for user programs using said part, such as
GCC 9 in its libsanitizer component[1]:

.../libsanitizer/sanitizer_common/sanitizer_platform_limits_posix.cc:160:10: fatal error: linux/cyclades.h: No such file or directory
  160 | #include <linux/cyclades.h>
      |          ^~~~~~~~~~~~~~~~~~
compilation terminated.
make[4]: *** [Makefile:664: sanitizer_platform_limits_posix.lo] Error 1

As the absolute minimum required bring `struct cyclades_monitor' and
ioctl numbers back then so as to make the library build again.  Add a
preprocessor warning as to the obsolescence of the features provided.

References:

[1] GCC PR sanitizer/100379, "cyclades.h is removed from linux kernel
    header files", <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100379>

Fixes: f76edd8f7c ("tty: cyclades, remove this orphan")
Cc: stable@vger.kernel.org # v5.13+
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Maciej W. Rozycki <macro@embecosm.com>
Link: https://lore.kernel.org/r/alpine.DEB.2.20.2201260733430.11348@tpp.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Maciej W. Rozycki 2022-01-26 09:22:54 +00:00 committed by Greg Kroah-Hartman
parent 152d1afa83
commit f23653fe64

View File

@ -0,0 +1,35 @@
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _UAPI_LINUX_CYCLADES_H
#define _UAPI_LINUX_CYCLADES_H
#warning "Support for features provided by this header has been removed"
#warning "Please consider updating your code"
struct cyclades_monitor {
unsigned long int_count;
unsigned long char_count;
unsigned long char_max;
unsigned long char_last;
};
#define CYGETMON 0x435901
#define CYGETTHRESH 0x435902
#define CYSETTHRESH 0x435903
#define CYGETDEFTHRESH 0x435904
#define CYSETDEFTHRESH 0x435905
#define CYGETTIMEOUT 0x435906
#define CYSETTIMEOUT 0x435907
#define CYGETDEFTIMEOUT 0x435908
#define CYSETDEFTIMEOUT 0x435909
#define CYSETRFLOW 0x43590a
#define CYGETRFLOW 0x43590b
#define CYSETRTSDTR_INV 0x43590c
#define CYGETRTSDTR_INV 0x43590d
#define CYZSETPOLLCYCLE 0x43590e
#define CYZGETPOLLCYCLE 0x43590f
#define CYGETCD1400VER 0x435910
#define CYSETWAIT 0x435912
#define CYGETWAIT 0x435913
#endif /* _UAPI_LINUX_CYCLADES_H */