kernel.git/drivers/tty/amiserial.c, branch linux-5.14.y

tty: make tty_operations::chars_in_buffer return uint

2021-05-13T16:29:11Z

tty_operations::chars_in_buffer is another hook which is expected to return values >= 0. So make it explicit by the return type too -- use unsigned int. Signed-off-by: Jiri Slaby Acked-By: Anton Ivanov Acked-by: David Sterba Cc: Jeff Dike Cc: Richard Weinberger Cc: Arnd Bergmann Cc: Samuel Iglesias Gonsalvez Cc: Jens Taprogge Cc: Karsten Keil Cc: Ulf Hansson Cc: "David S. Miller" Cc: Jakub Kicinski Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: David Lin Cc: Johan Hovold Cc: Alex Elder Cc: Jiri Kosina Cc: Shawn Guo Cc: Sascha Hauer Cc: Oliver Neukum Cc: Felipe Balbi Cc: Mathias Nyman Cc: Marcel Holtmann Cc: Johan Hedberg Cc: Luiz Augusto von Dentz Link: https://lore.kernel.org/r/20210505091928.22010-27-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: make tty_operations::write_room return uint

2021-05-13T15:03:20Z

Line disciplines expect a positive value or zero returned from tty->ops->write_room (invoked by tty_write_room). So make this assumption explicit by using unsigned int as a return value. Both of tty->ops->write_room and tty_write_room. Signed-off-by: Jiri Slaby Acked-by: Laurentiu Tudor Acked-by: Alex Elder Acked-by: Max Filippov # xtensa Acked-by: David Sterba Acked-By: Anton Ivanov Acked-by: Geert Uytterhoeven Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: Jeff Dike Cc: Richard Weinberger Cc: Chris Zankel Cc: Arnd Bergmann Cc: Samuel Iglesias Gonsalvez Cc: Jens Taprogge Cc: Karsten Keil Cc: Scott Branden Cc: Ulf Hansson Cc: "David S. Miller" Cc: Jakub Kicinski Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: David Lin Cc: Johan Hovold Cc: Jiri Kosina Cc: Shawn Guo Cc: Sascha Hauer Cc: Oliver Neukum Cc: Felipe Balbi Cc: Mathias Nyman Cc: Marcel Holtmann Cc: Johan Hedberg Cc: Luiz Augusto von Dentz Link: https://lore.kernel.org/r/20210505091928.22010-23-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: cumulate and document tty_struct::flow* members

2021-05-13T14:57:16Z

Group the flow flags under a single struct called flow. The new struct contains 'stopped' and 'tco_stopped' bools which used to be bits in a bitfield. The struct also contains the lock protecting them to potentially share the same cache line. Note that commit c545b66c6922b (tty: Serialize tcflow() with other tty flow control changes) added a padding to the original bitfield. It was for the bitfield to occupy a whole 64b word to avoid interferring stores on Alpha (cannot we evaporate this arch with weird implications to C code yet?). But it doesn't work as expected as the padding (tty_struct::unused) is aligned to a 8B boundary too and occupies some bytes from the next word. So make it reliable by: 1) setting __aligned of the struct -- that aligns the start, and 2) making 'unsigned long unused[0]' as the last member of the struct -- pads the end. This is also the perfect time to start the documentation of tty_struct where all this lives. So we start by documenting what these bools actually serve for. And why we do all the alignment dances. Only the few up-to-date information from the Theodore's comment made it into this new Kerneldoc comment. Signed-off-by: Jiri Slaby Cc: "David S. Miller" Cc: Jakub Kicinski Cc: Jonathan Corbet Cc: Arnd Bergmann Cc: Ulf Hansson Cc: Heiko Carstens Cc: Vasily Gorbik Cc: Christian Borntraeger Cc: Shawn Guo Cc: Sascha Hauer Cc: Vineet Gupta Cc: "Maciej W. Rozycki" Link: https://lore.kernel.org/r/20210505091928.22010-13-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: amiserial: add missing TIOCSSERIAL jiffies conversions

2021-04-07T15:22:07Z

The tty-port close_delay and closing_wait parameters set by TIOCSSERIAL are specified in jiffies, while the values returned by TIOCGSERIAL are specified in centiseconds. Add the missing conversions so that TIOCSSERIAL works as expected also if this code is ever reused on a system where HZ is not 100. Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210407102334.32361-10-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: amiserial: fix TIOCSSERIAL permission check

2021-04-07T15:22:07Z

Changing the port closing_wait parameter is a privileged operation. Add the missing check to TIOCSSERIAL so that -EPERM is returned in case an unprivileged user tries to change the closing-wait setting. Cc: stable@vger.kernel.org Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210407102334.32361-9-johan@kernel.org Signed-off-by: Greg Kroah-Hartman

tty: do not check tty_unregister_driver's return value

2021-03-10T08:34:09Z

These drivers check tty_unregister_driver return value. But they don't handle a failure correctly (they free the driver in any case). So stop checking tty_unregister_driver return value and remove also the prints. In the next patch, tty_unregister_driver's return type will be switched to void. Cc: Chris Zankel Cc: Max Filippov Cc: linux-xtensa@linux-xtensa.org Cc: Jiri Kosina Cc: David Sterba Reviewed-by: Max Filippov Acked-by: David Sterba Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210302062214.29627-34-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty_port: drop last traces of low_latency

2021-01-07T15:17:32Z

The main purpose of tty_port::low_latency was removed in commit a9c3f68f3cd8 (tty: Fix low_latency BUG) back in 2014. It was left in place for drivers as an optional tune knob. But only one driver has been using it until the previous commit. So remove this misconcept completely, given there are no users. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210105120239.28031-11-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

Remove every trace of SERIAL_MAGIC

2019-11-13T11:01:14Z

This means removing support for checking magic in amiserial.c (SERIAL_PARANOIA_CHECK option), which was checking a magic field which doesn't currently exist in the struct. That code hasn't built at least since git. Removing the definition from the header is safe anyway as that code was from another driver and not including it. Signed-off-by: Pascal Terjan Reviewed-by: Geert Uytterhoeven Link: https://lore.kernel.org/r/20191105192749.67533-1-pterjan@google.com Signed-off-by: Greg Kroah-Hartman

kill TIOCSERGSTRUCT

2018-10-13T04:50:53Z

Once upon a time a bunch of serial drivers used to provide that; today it's only amiserial and it's FUBAR - the structure being copied to userland includes kernel pointers, fields with config-dependent size, etc. No userland code using it could possibly survive - e.g. enabling lockdep definitely changes the layout. Besides, it's a massive infoleak. Kill it. If somebody needs that data for debugging purposes, they can bloody well expose it saner ways. Assuming anyone does debugging of amiserial in the first place, that is. Signed-off-by: Al Viro

kill TIOCSER[SG]WILD

2018-10-13T04:50:52Z

the only user is very old setserial rc script and even that (as far back as MCC Interim, AFAICS) doesn't actually fail - just gives one message during the boot ("Cannot scan for wild interrupts") and proceeds past that just fine. Signed-off-by: Al Viro