user/sven/linux.git/include/linux/tty.h, branch v3.9.11

tty: Added a CONFIG_TTY option to allow removal of TTY

2013-01-19T00:15:27Z

The option allows you to remove TTY and compile without errors. This saves space on systems that won't support TTY interfaces anyway. bloat-o-meter output is below. The bulk of this patch consists of Kconfig changes adding "depends on TTY" to various serial devices and similar drivers that require the TTY layer. Ideally, these dependencies would occur on a common intermediate symbol such as SERIO, but most drivers "select SERIO" rather than "depends on SERIO", and "select" does not respect dependencies. bloat-o-meter output comparing our previous minimal to new minimal by removing TTY. The list is filtered to not show removed entries with awk '$3 != "-"' as the list was very long. add/remove: 0/226 grow/shrink: 2/14 up/down: 6/-35356 (-35350) function old new delta chr_dev_init 166 170 +4 allow_signal 80 82 +2 static.__warned 143 142 -1 disallow_signal 63 62 -1 __set_special_pids 95 94 -1 unregister_console 126 121 -5 start_kernel 546 541 -5 register_console 593 588 -5 copy_from_user 45 40 -5 sys_setsid 128 120 -8 sys_vhangup 32 19 -13 do_exit 1543 1526 -17 bitmap_zero 60 40 -20 arch_local_irq_save 137 117 -20 release_task 674 652 -22 static.spin_unlock_irqrestore 308 260 -48 Signed-off-by: Joe Millenbach Reviewed-by: Jamey Sharp Reviewed-by: Josh Triplett Signed-off-by: Greg Kroah-Hartman

TTY: switch tty_flip_buffer_push

2013-01-16T06:30:15Z

Now, we start converting tty buffer functions to actually use tty_port. This will allow us to get rid of the need of tty in many call sites. Only tty_port will needed and hence no more tty_port_tty_get in those paths. Now, the one where most of tty_port_tty_get gets removed: tty_flip_buffer_push. IOW we also closed all the races in drivers not using tty_port_tty_get at all yet. Also we move tty_flip_buffer_push declaration from include/linux/tty.h to include/linux/tty_flip.h to all others while we are changing it anyway. Signed-off-by: Jiri Slaby Signed-off-by: Greg Kroah-Hartman

TTY: move low_latency to tty_port

2013-01-16T06:23:16Z

One point is to have less places where we actually need tty pointer. The other is that low_latency is bound to buffer processing and buffers are now in tty_port. So it makes sense to move low_latency to tty_port too. Signed-off-by: Jiri Slaby Signed-off-by: Greg Kroah-Hartman

TTY: introduce tty_port_destroy

2012-11-16T01:20:58Z

After commit "TTY: move tty buffers to tty_port", the tty buffers are not freed in some drivers. This is because tty_port_destructor is not called whenever a tty_port is freed. This was an assumption I counted with but was unfortunately untrue. Those using refcounting are safe now, but for those which do not we introduce a function to be called right before the tty_port is freed by the drivers. Signed-off-by: Jiri Slaby Signed-off-by: Greg Kroah-Hartman

TTY: move tty buffers to tty_port

2012-10-22T23:58:28Z

So this is it. The big step why we did all the work over the past kernel releases. Now everything is prepared, so nothing protects us from doing that big step. | | \ \ nnnn/^l | | | | \ / / | | | '-,.__ => \/ ,-` => | '-,.__ | O __.´´) ( .` | O __.´´) ~~~ ~~ `` ~~~ ~~ The buffers are now in the tty_port structure and we can start teaching the buffer helpers (insert char/string, flip etc.) to use tty_port instead of tty_struct all around. Signed-off-by: Jiri Slaby Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman

TTY: add port -> tty link

2012-10-22T23:53:40Z

For that purpose we have to temporarily introduce a second tty back pointer into tty_port. It is because serial layer, and maybe others, still do not use tty_port_tty_set/get. So that we cannot set the tty_port->tty to NULL at will now. Yes, the fix would be to convert whole serial layer and all its users to tty_port_tty_set/get. However we are in the process of removing the need of tty in most of the call sites, so this would lead to a duplicated work. Instead we have now tty_port->itty (internal tty) which will be used only in flush_to_ldisc. For that one it is ensured that itty is valid wherever the work is run. IOW, the work is synchronously cancelled before we set itty to NULL and also before hangup is processed. After we need only tty_port and not tty_struct in most code, this shall be changed to tty_port_tty_set/get and itty removed completely. Signed-off-by: Jiri Slaby Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman

TTY: move TTY_FLUSH* flags to tty_port

2012-10-22T23:53:21Z

They are only TTY buffers specific. And the buffers will go to tty_port in the next patches. So to remove the need to have both tty_port and tty_struct at some places, let us move the flags to tty_port. Signed-off-by: Jiri Slaby Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman

TTY: move ldisc data from tty_struct: locks

2012-10-22T23:53:01Z

atomic_write_lock is not n_tty specific, so move it up in the tty_struct. And since these are the last ones to move, remove also the comment saying there are some ldisc' members. There are none now. Signed-off-by: Jiri Slaby Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman

TTY: move ldisc data from tty_struct: read_* and echo_* and canon_* stuff

2012-10-22T23:53:01Z

All the ring-buffers... Signed-off-by: Jiri Slaby Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman

TTY: move ldisc data from tty_struct: bitmaps

2012-10-22T23:53:00Z

Here we move bitmaps and use DECLARE_BITMAP to declare them in the new structure. And instead of memset, we use bitmap_zero as it is more appropriate. Signed-off-by: Jiri Slaby Acked-by: Alan Cox Signed-off-by: Greg Kroah-Hartman