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path: root/drivers/s390/char/sclp_tty.c
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2008-07-14[S390] sclp_tty: Fix scheduling while atomic bug.Heiko Carstens
Finally fixes a possible scheduling while in atomic context bug. The driver used to wait on a waitqueue if no empty buffer was available. This could lead to a deadlock if the driver was called from non-schedulable context. So fix this. The write operation may fail now. It returns the number of characters accepted. put_char will never fail, since it writes characters to an intermediate buffer which gets flushed as soon as it is full. That means the driver now can busy wait if something is in the intermediate buffer and a write_string operation follows. Seems to be an acceptable compromise, since that shouldn't happen too often. Cc: Peter Oberparleiter <peter.oberparleiter@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-07-14[S390] sclp_tty: remove ioctl interface.Heiko Carstens
After all we came to the conclusion that this interface doesn't make any sense. Besides that the ioctl number used was never registered, the header file isn't exported, and we doubt there is even a single user. So remove this interface, since it eases maintenance. Cc: Peter Oberparleiter <peter.oberparleiter@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-07-14[S390] Cleanup sclp printk messages.Martin Schwidefsky
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2008-04-30s390 tty: Prepare for put_char to return success/failAlan Cox
Put the changes into the drivers first. This will still compile/work but produce a warning if bisected so can still be debugged Signed-off-by: Alan Cox <alan@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Peter Oberparleiter <peter.oberparleiter@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-17[S390] sclp: Get rid of in_atomic() use.Heiko Carstens
Reintroduces in_interrupt() check in sclp_tty code. Add may_schedule parameter to vt220 write function, so we can let the write function know if it may schedule or not. So we disallow scheduling for all console calls and may allow them for tty calls. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2008-02-05[S390] sclp_tty/sclp_vt220: Fix scheduling while atomicChristian Borntraeger
Under load the following bug message appeared while using sysrq-t: BUG: scheduling while atomic: bash/3662/0x00000004 0000000000105b74 000000003ba17740 0000000000000002 0000000000000000 000000003ba177e0 000000003ba17758 000000003ba17758 0000000000105bfe 0000000000817ba8 000000003f2a5350 0000000000000000 0000000000000000 000000003ba17740 000000000000000c 000000003ba17740 000000003ba177b0 0000000000568630 0000000000105bfe 000000003ba17740 000000003ba17790 Call Trace: ([<0000000000105b74>] show_trace+0x13c/0x158) [<0000000000105c58>] show_stack+0xc8/0xfc [<0000000000105cbc>] dump_stack+0x30/0x40 [<000000000012a0c8>] __schedule_bug+0x84/0x94 [<000000000056234e>] schedule+0x5ea/0x970 [<0000000000477cd2>] __sclp_vt220_write+0x1f6/0x3ec [<0000000000477f00>] sclp_vt220_con_write+0x38/0x48 [<0000000000130b4a>] __call_console_drivers+0xbe/0xd8 [<0000000000130bf0>] _call_console_drivers+0x8c/0xd0 [<0000000000130eea>] release_console_sem+0x1a6/0x2fc [<0000000000131786>] vprintk+0x262/0x480 [<00000000001319fa>] printk+0x56/0x68 [<0000000000125aaa>] print_cfs_rq+0x45e/0x4a4 [<000000000012614e>] sched_debug_show+0x65e/0xee8 [<000000000012a8fc>] show_state_filter+0x1cc/0x1f0 [<000000000044d39c>] sysrq_handle_showstate+0x2c/0x3c [<000000000044d1fe>] __handle_sysrq+0xae/0x18c [<00000000002001f2>] write_sysrq_trigger+0x8a/0x90 [<00000000001f7862>] proc_reg_write+0x9a/0xc4 [<00000000001a83d4>] vfs_write+0xb8/0x174 [<00000000001a8b88>] sys_write+0x58/0x8c [<0000000000112e7c>] sysc_noemu+0x10/0x16 [<0000020000116f68>] 0x20000116f68 The problem seems to be, that with a full console buffer, release_console_sem disables interrupts with spin_lock_irqsave and then calls the console function without enabling interrupts. __sclp_vt220_write checks for in_interrupt, to decide if it can schedule. It should check for in_atomic instead. The same is true for sclp_tty.c. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-04-27[S390] sclp: fix coding style.Stefan Haberland
Use only capital letters for defines. Cc: Peter Oberparleiter <peter.oberparleiter@de.ibm.com> Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2007-02-14[PATCH] remove many unneeded #includes of sched.hTim Schmielau
After Al Viro (finally) succeeded in removing the sched.h #include in module.h recently, it makes sense again to remove other superfluous sched.h includes. There are quite a lot of files which include it but don't actually need anything defined in there. Presumably these includes were once needed for macros that used to live in sched.h, but moved to other header files in the course of cleaning it up. To ease the pain, this time I did not fiddle with any header files and only removed #includes from .c-files, which tend to cause less trouble. Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha, arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig, allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all configs in arch/arm/configs on arm. I also checked that no new warnings were introduced by the patch (actually, some warnings are removed that were emitted by unnecessarily included header files). Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-05[S390] Get rid of a lot of sparse warnings.Heiko Carstens
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2006-12-08[PATCH] tty: switch to ktermiosAlan Cox
This is the grungy swap all the occurrences in the right places patch that goes with the updates. At this point we have the same functionality as before (except that sgttyb() returns speeds not zero) and are ready to begin turning new stuff on providing nobody reports lots of bugs If you are a tty driver author converting an out of tree driver the only impact should be termios->ktermios name changes for the speed/property setting functions from your upper layers. If you are implementing your own TCGETS function before then your driver was broken already and its about to get a whole lot more painful for you so please fix it 8) Also fill in c_ispeed/ospeed on init for most devices, although the current code will do this for you anyway but I'd like eventually to lose that extra paranoia [akpm@osdl.org: bluetooth fix] [mp3@de.ibm.com: sclp fix] [mp3@de.ibm.com: warning fix for tty3270] [hugh@veritas.com: fix tty_ioctl powerpc build] [jdike@addtoit.com: uml: fix ->set_termios declaration] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Martin Peschke <mp3@de.ibm.com> Acked-by: Peter Oberparleiter <oberpar@de.ibm.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-02[PATCH] const struct tty_operationsJeff Dike
As part of an SMP cleanliness pass over UML, I consted a bunch of structures in order to not have to document their locking. One of these structures was a struct tty_operations. In order to const it in UML without introducing compiler complaints, the declaration of tty_set_operations needs to be changed, and then all of its callers need to be fixed. This patch declares all struct tty_operations in the tree as const. In all cases, they are static and used only as input to tty_set_operations. As an extra check, I ran an i386 allyesconfig build which produced no extra warnings. 53 drivers are affected. I checked the history of a bunch of them, and in most cases, there have been only a handful of maintenance changes in the last six months. serial_core.c was the busiest one that I looked at. Signed-off-by: Jeff Dike <jdike@addtoit.com> Acked-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-30Remove obsolete #include <linux/config.h>Jörn Engel
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-01-10[PATCH] TTY layer buffering revampAlan Cox
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>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
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!