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path: root/drivers/tty/vt/selection.c (follow)
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* tty: Fix unsafe vt paste_selection()Peter Hurley2013-07-241-1/+3
| | | | | | | | | | Convert the tty_buffer_flush() exclusion mechanism to a public interface - tty_buffer_lock/unlock_exclusive() - and use the interface to safely write the paste selection to the line discipline. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Make ldisc input flow control concurrency-friendlyPeter Hurley2013-07-241-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Although line discipline receiving is single-producer/single-consumer, using tty->receive_room to manage flow control creates unnecessary critical regions requiring additional lock use. Instead, introduce the optional .receive_buf2() ldisc method which returns the # of bytes actually received. Serialization is guaranteed by the caller. In turn, the line discipline should schedule the buffer work item whenever space becomes available; ie., when there is room to receive data and receive_room() previously returned 0 (the buffer work item stops processing if receive_buf2() returns 0). Note the 'no room' state need not be atomic despite concurrent use by two threads because only the buffer work thread can set the state and only the read() thread can clear the state. Add n_tty_receive_buf2() as the receive_buf2() method for N_TTY. Provide a public helper function, tty_ldisc_receive_buf(), to use when directly accessing the receive_buf() methods. Line disciplines not using input flow control can continue to set tty->receive_room to a fixed value and only provide the receive_buf() method. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* TTY: vt, fix paste_selection ldisc handlingJiri Slaby2012-10-231-7/+2
| | | | | | | | | | | | | | | There used to be a single tty_ldisc_ref_wait. But then, when a big-tty-mutex (BTM) was introduced, it has to be tty_ldisc_ref + tty_unlock + tty_ldisc_ref_wait + tty_lock. Later, BTM was removed from that path and tty_ldisc_ref + tty_ldisc_ref_wait remained there. But it makes no sense now. So leave there only tty_ldisc_ref_wait. And when we have a reference to an ldisc, actually use it in the loop. Otherwise it may be racy. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* vt: tackle the main part of the selection logicAlan Cox2012-03-081-8/+31
| | | | | | | | We leave the existing paste mess alone and just fix up the vt side of things. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* vt: push down tioclinux casesAlan Cox2012-03-081-6/+6
| | | | | | | | Some of this ventures into selection which is still a complete lost cause. We are not making it any worse. It's completely busted anyway. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* vt:tackle kbd_tableAlan Cox2012-03-081-2/+7
| | | | | | | | | | | | | | | | | | | | | Keyboard struct lifetime is easy, but the locking is not and is completely ignored by the existing code. Tackle this one head on - Make the kbd_table private so we can run down all direct users - Hoick the relevant ioctl handlers into the keyboard layer - Lock them with the keyboard lock so they don't change mid keypress - Add helpers for things like console stop/start so we isolate the poking around properly - Tweak the braille console so it still builds There are a couple of FIXME locking cases left for ioctls that are so hideous they should be addressed in a later patch. After this patch the kbd_table is private and all the keyboard jiggery pokery is in one place. This update fixes speakup and also a memory leak in the original. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* TTY: remove tty_lockedJiri Slaby2011-08-231-2/+2
| | | | | | | | | | | | We used it really only serial and ami_serial. The rest of the callsites were BUG/WARN_ONs to check if BTM is held. Now that we pruned tty_locked from both of the real users, we can get rid of tty_lock along with __big_tty_mutex_owner. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Revert "tty: make receive_buf() return the amout of bytes received"Linus Torvalds2011-06-031-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit b1c43f82c5aa265442f82dba31ce985ebb7aa71c. It was broken in so many ways, and results in random odd pty issues. It re-introduced the buggy schedule_work() in flush_to_ldisc() that can cause endless work-loops (see commit a5660b41af6a: "tty: fix endless work loop when the buffer fills up"). It also used an "unsigned int" return value fo the ->receive_buf() function, but then made multiple functions return a negative error code, and didn't actually check for the error in the caller. And it didn't actually work at all. BenH bisected down odd tty behavior to it: "It looks like the patch is causing some major malfunctions of the X server for me, possibly related to PTYs. For example, cat'ing a large file in a gnome terminal hangs the kernel for -minutes- in a loop of what looks like flush_to_ldisc/workqueue code, (some ftrace data in the quoted bits further down). ... Some more data: It -looks- like what happens is that the flush_to_ldisc work queue entry constantly re-queues itself (because the PTY is full ?) and the workqueue thread will basically loop forver calling it without ever scheduling, thus starving the consumer process that could have emptied the PTY." which is pretty much exactly the problem we fixed in a5660b41af6a. Milton Miller pointed out the 'unsigned int' issue. Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reported-by: Milton Miller <miltonm@bga.com> Cc: Stefan Bigler <stefan.bigler@keymile.com> Cc: Toby Gray <toby.gray@realvnc.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: make receive_buf() return the amout of bytes receivedFelipe Balbi2011-04-231-2/+1
| | | | | | | | | | | | | it makes it simpler to keep track of the amount of bytes received and simplifies how flush_to_ldisc counts the remaining bytes. It also fixes a bug of lost bytes on n_tty when flushing too many bytes via the USB serial gadget driver. Tested-by: Stefan Bigler <stefan.bigler@keymile.com> Tested-by: Toby Gray <toby.gray@realvnc.com> Signed-off-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* tty: remove invalid location line in file headerJovi Zhang2011-04-201-2/+0
| | | | | | | | remove invalid location line in each file header after location moved from driver/char to driver/tty Signed-off-by: Jovi Zhang <bookjovi@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* drivers: remove extraneous includes of smp_lock.hArnd Bergmann2011-03-021-1/+0
| | | | | | | | These were missed the last time I cleaned this up globally, because of code moving around or new code getting merged. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* console: rename acquire/release_console_sem() to console_lock/unlock()Torben Hohn2011-01-261-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | The -rt patches change the console_semaphore to console_mutex. As a result, a quite large chunk of the patches changes all acquire/release_console_sem() to acquire/release_console_mutex() This commit makes things use more neutral function names which dont make implications about the underlying lock. The only real change is the return value of console_trylock which is inverted from try_acquire_console_sem() This patch also paves the way to switching console_sem from a semaphore to a mutex. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: make console_trylock return 1 on success, per Geert] Signed-off-by: Torben Hohn <torbenh@gmx.de> Cc: Thomas Gleixner <tglx@tglx.de> Cc: Greg KH <gregkh@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* TTY: create drivers/tty/vt and move the vt code thereGreg Kroah-Hartman2010-11-051-0/+348
The vt and other related code is moved into the drivers/tty/vt directory. Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>