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* tty: move global ldisc idle waitqueue to the individual ldiscIvo Sieben2012-05-101-0/+2
| | | | | | | | | | | The global wait_queue that is used for line discipline idle handling is moved to a separate wait_queue for each line instance. This prevents unnecessary blocking on one line, because of idle handling on another line. Signed-off-by: Ivo Sieben <meltedpianoman@gmail.com> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "tty: make receive_buf() return the amout of bytes received"Linus Torvalds2011-06-041-5/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Balbi2011-04-221-4/+5
| | | | | | | | | | | | | 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>
* pps: timestamp is always passed to dcd_change()Alexander Gordeev2011-01-131-1/+1
| | | | | | | | | | | Remove the code that gatheres timestamp in pps_tty_dcd_change() in case passed ts parameter is NULL because it never happens in the current code. Fix comments as well. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pps: unify timestamp gatheringAlexander Gordeev2011-01-131-2/+3
| | | | | | | | | | Add a helper function to gather timestamps. This way clients don't have to duplicate it. Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su> Acked-by: Rodolfo Giometti <giometti@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ldisc: new dcd_change() method for line disciplinesRodolfo Giometti2010-03-121-0/+8
| | | | | | | | | | Signed-off-by: Rodolfo Giometti <giometti@linux.it> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Greg KH <greg@kroah.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty-ldisc: make refcount be atomic_t 'users' countLinus Torvalds2009-08-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | This is pure preparation of changing the ldisc reference counting to be a true refcount that defines the lifetime of the ldisc. But this is a purely syntactic change for now to make the next steps easier. This patch should make no semantic changes at all. But I wanted to make the ldisc refcount be an atomic (I will be touching it without locks soon enough), and I wanted to rename it so that there isn't quite as much confusion between 'ldo->refcount' (ldisk operations refcount) and 'ld->refcount' (ldisc refcount itself) in the same file. So it's now an atomic 'ld->users' count. It still starts at zero, despite having a reference from 'tty->ldisc', but that will change once we turn it into a _real_ refcount. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Tested-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@mail.by> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* tty: Ldisc revampAlan Cox2008-07-201-1/+6
| | | | | | | | | | | | Move the line disciplines towards a conventional ->ops arrangement. For the moment the actual 'tty_ldisc' struct in the tty is kept as part of the tty struct but this can then be changed if it turns out that when it all settles down we want to refcount ldiscs separately to the tty. Pull the ldisc code out of /proc and put it with our ldisc code. Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: add compat_ioctlPaul Fulghum2007-05-111-0/+7
| | | | | | | | | | | | | | | Add compat_ioctl method for tty code to allow processing of 32 bit ioctl calls on 64 bit systems by tty core, tty drivers, and line disciplines. Based on patch by Arnd Bergmann: http://www.uwsg.iu.edu/hypermail/linux/kernel/0511.0/1732.html [akpm@linux-foundation.org: make things static] Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] tty: switch to ktermios and new frameworkAlan Cox2006-12-081-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | This is the core of the switch to the new framework. I've split it from the driver patches which are mostly search/replace and would encourage people to give this one a good hard stare. The references to BOTHER and ISHIFT are the termios values that must be defined by a platform once it wants to turn on "new style" ioctl support. The code patches here ensure that providing 1. The termios overlays the ktermios in memory 2. The only new kernel only fields are c_ispeed/c_ospeed (or none) the existing behaviour is retained. This is true for the patches at this point in time. Future patches will define BOTHER, ISHIFT and enable newer termios structures for each architecture, and once they are all done some of the ifdefs also vanish. [akpm@osdl.org: warning fix] [akpm@osdl.org: IRDA fix] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] TTY layer buffering revampAlan Cox2006-01-101-9/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The API and code have been through various bits of initial review by serial driver people but they definitely need to live somewhere for a while so the unconverted drivers can get knocked into shape, existing drivers that have been updated can be better tuned and bugs whacked out. This replaces the tty flip buffers with kmalloc objects in rings. In the normal situation for an IRQ driven serial port at typical speeds the behaviour is pretty much the same, two buffers end up allocated and the kernel cycles between them as before. When there are delays or at high speed we now behave far better as the buffer pool can grow a bit rather than lose characters. This also means that we can operate at higher speeds reliably. For drivers that receive characters in blocks (DMA based, USB and especially virtualisation) the layer allows a lot of driver specific code that works around the tty layer with private secondary queues to be removed. The IBM folks need this sort of layer, the smart serial port people do, the virtualisers do (because a virtualised tty typically operates at infinite speed rather than emulating 9600 baud). Finally many drivers had invalid and unsafe attempts to avoid buffer overflows by directly invoking tty methods extracted out of the innards of work queue structs. These are no longer needed and all go away. That fixes various random hangs with serial ports on overflow. The other change in here is to optimise the receive_room path that is used by some callers. It turns out that only one ldisc uses receive room except asa constant and it updates it far far less than the value is read. We thus make it a variable not a function call. I expect the code to contain bugs due to the size alone but I'll be watching and squashing them and feeding out new patches as it goes. Because the buffers now dynamically expand you should only run out of buffering when the kernel runs out of memory for real. That means a lot of the horrible hacks high performance drivers used to do just aren't needed any more. Description: tty_insert_flip_char is an old API and continues to work as before, as does tty_flip_buffer_push() [this is why many drivers dont need modification]. It does now also return the number of chars inserted There are also tty_buffer_request_room(tty, len) which asks for a buffer block of the length requested and returns the space found. This improves efficiency with hardware that knows how much to transfer. and tty_insert_flip_string_flags(tty, str, flags, len) to insert a string of characters and flags For a smart interface the usual code is len = tty_request_buffer_room(tty, amount_hardware_says); tty_insert_flip_string(tty, buffer_from_card, len); More description! At the moment tty buffers are attached directly to the tty. This is causing a lot of the problems related to tty layer locking, also problems at high speed and also with bursty data (such as occurs in virtualised environments) I'm working on ripping out the flip buffers and replacing them with a pool of dynamically allocated buffers. This allows both for old style "byte I/O" devices and also helps virtualisation and smart devices where large blocks of data suddenely materialise and need storing. So far so good. Lots of drivers reference tty->flip.*. Several of them also call directly and unsafely into function pointers it provides. This will all break. Most drivers can use tty_insert_flip_char which can be kept as an API but others need more. At the moment I've added the following interfaces, if people think more will be needed now is a good time to say int tty_buffer_request_room(tty, size) Try and ensure at least size bytes are available, returns actual room (may be zero). At the moment it just uses the flipbuf space but that will change. Repeated calls without characters being added are not cumulative. (ie if you call it with 1, 1, 1, and then 4 you'll have four characters of space. The other functions will also try and grow buffers in future but this will be a more efficient way when you know block sizes. int tty_insert_flip_char(tty, ch, flag) As before insert a character if there is room. Now returns 1 for success, 0 for failure. int tty_insert_flip_string(tty, str, len) Insert a block of non error characters. Returns the number inserted. int tty_prepare_flip_string(tty, strptr, len) Adjust the buffer to allow len characters to be added. Returns a buffer pointer in strptr and the length available. This allows for hardware that needs to use functions like insl or mencpy_fromio. Signed-off-by: Alan Cox <alan@redhat.com> Cc: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: John Hawkes <hawkes@sgi.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-161-0/+154
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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