When the console has been redirected, a hangup of the tty
will cause tty_release to be called under the big tty_mutex,
which leads to a deadlock because hangup is also called
under the BTM.
This moves the BTM deeper into the tty_hangup function so
we can close the redirected tty without holding the BTM.
In case of pty, we now need to drop the BTM before
calling tty_vhangup.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This changes all remaining users of tty_lock_nested
to be non-recursive, which lets us kill this function.
As a consequence, we won't need to keep the lock count
any more, which allows more simplifications later.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
tty_mutex is never taken with the BTM held, except for
two corner cases that are worked around here.
We give up the BTM before calling tty_release() in the
error path of tty_open().
Similarly, we reorder the locking in ptmx_open()
to get tty_mutex before the BTM.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
As a preparation for replacing the big kernel lock
in the TTY layer, wrap all the callers in new
macros tty_lock, tty_lock_nested and tty_unlock.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch is against the 2.6.34 source.
Paraphrased from the 1989 BSD patch by David Borman @ cray.com:
These are the changes needed for the kernel to support
LINEMODE in the server.
There is a new bit in the termios local flag word, EXTPROC.
When this bit is set, several aspects of the terminal driver
are disabled. Input line editing, character echo, and mapping
of signals are all disabled. This allows the telnetd to turn
off these functions when in linemode, but still keep track of
what state the user wants the terminal to be in.
New ioctl:
TIOCSIG Generate a signal to processes in the
current process group of the pty.
There is a new mode for packet driver, the TIOCPKT_IOCTL bit.
When packet mode is turned on in the pty, and the EXTPROC bit
is set, then whenever the state of the pty is changed, the
next read on the master side of the pty will have the TIOCPKT_IOCTL
bit set. This allows the process on the server side of the pty
to know when the state of the terminal has changed; it can then
issue the appropriate ioctl to retrieve the new state.
Since the original BSD patches accompanied the source code for telnet
I've left that reference here, but obviously the feature is useful for
any remote terminal protocol, including ssh.
The corresponding feature has existed in the BSD tty driver since 1989.
For historical reference, a good copy of the relevant files can be found
here:
http://anonsvn.mit.edu/viewvc/krb5/trunk/src/appl/telnet/?pathrev=17741
Signed-off-by: Howard Chu <hyc@symas.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
In particular, several occurances of funny versions of 'success',
'unknown', 'therefore', 'acknowledge', 'argument', 'achieve', 'address',
'beginning', 'desirable', 'separate' and 'necessary' are fixed.
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Joe Perches <joe@perches.com>
Cc: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Start trying to untangle the remaining BKL mess
Updated to fix missing unlock_kernel noted by Dan Carpenter
Signed-off-by: Alan "I must be out of my tree" Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
For consistency drop & in front of every proc_handler. Explicity
taking the address is unnecessary and it prevents optimizations
like stubbing the proc_handlers to NULL.
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Now that sys_sysctl is a wrapper around /proc/sys all of
the binary sysctl support elsewhere in the tree is
dead code.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Corey Minyard <minyard@acm.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Neil Brown <neilb@suse.de>
Cc: "James E.J. Bottomley" <James.Bottomley@suse.de>
Acked-by: Clemens Ladisch <clemens@ladisch.de> for drivers/char/hpet.c
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
After m68k's task_thread_info() doesn't refer to current,
it's possible to remove sched.h from interrupt.h and not break m68k!
Many thanks to Heiko Carstens for allowing this.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
David Howells noticed (due to the compiler warning about an unused
'pty_ops_bsd' variable) that we haven't actually been using the code
that implements TIOCSPTLCK for legacy pty handling. It's been that way
since 2.6.26, commit 3e8e88ca05 to be
exact ("pty: prepare for tty->ops changes").
DavidH initially submitted a patch just removing the dead code entirely,
and since nobody has apparently ever complained, I'm not entirely sure
that wouldn't be the right thing to do. But since the whole and only
point of the legacy pty code is to be compatible with legacy distros
that don't use the new unix98 pty model, let's just wire it up again.
And clean it up a bit while we're at it.
Acked-by: David Howells <dhowells@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit ac89a9174 ("pty: don't limit the writes to 'pty_space()' inside
'pty_write()'") removed the pty_space() checking, in order to let the
regular tty buffer code limit the buffering itself.
That was all good, but as a subtle side effect it meant that we'd be
doing a tty_wakeup() even in the case where the buffers were all filled
up, and didn't actually make any progress on the write.
Which sounds innocuous, but it interacts very badly with the ppp_async
code, which has an infinite loop in ppp_async_push() that tries to push
out data to the tty. When we call tty_wakeup(), that loop ends up
thinking that progress was made (see the subtle interactions between
XMIT_WAKEUP and 'tty_stuffed' for details). End result: one unhappy ppp
user.
Fixed by noticing when tty_insert_flip_string() didn't actually do
anything, and then not doing any more processing (including, very much
not calling tty_wakeup()).
Bisected-and-tested-by: Peter Volkov <pva@gentoo.org>
Cc: stable@kernel.org (2.6.31)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The whole write-room thing is something that is up to the _caller_ to
worry about, not the pty layer itself. The total buffer space will
still be limited by the buffering routines themselves, so there is no
advantage or need in having pty_write() artificially limit the size
somehow.
And what happened was that the caller (the n_tty line discipline, in
this case) may have verified that there is room for 2 bytes to be
written (for NL -> CRNL expansion), and it used to then do those writes
as two single-byte writes. And if the first byte written (CR) then
caused a new tty buffer to be allocated, pty_space() may have returned
zero when trying to write the second byte (LF), and then incorrectly
failed the write - leading to a lost newline character.
This should finally fix
http://bugzilla.kernel.org/show_bug.cgi?id=14015
Reported-by: Mikael Pettersson <mikpe@it.uu.se>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit d945cb9cc ("pty: Rework the pty layer to use the normal buffering
logic") dropped the test for 'tty->stopped' in pty_write_room(), which
then causes the n_tty line discipline thing to not throttle the data
properly when the tty is stopped.
So instead of pausing the write due to the tty being stopped, the ldisc
layer would go ahead and push it down to the pty. The pty write()
routine would then refuse to take the data (because it _did_ check
'stopped'), and the data wouldn't actually be written.
This whole stopped test should eventually be moved into the tty ldisc
layer rather than have low-level tty drivers care about these things,
but right now the fix is to just re-instate the missing pty 'stopped'
handling.
Reported-and-tested-by: Artur Skawina <art.08.09@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We really don't want to mark the pty as a low-latency device, because as
Alan points out, the ->write method can be called from an IRQ (ppp?),
and that means we can't use ->low_latency=1 as we take mutexes in the
low_latency case.
So rather than using low_latency to force the written data to be pushed
to the ldisc handling at 'write()' time, just make the reader side (or
the poll function) do the flush when it checks whether there is data to
be had.
This also fixes the problem with lost data in an emacs compile buffer
(bugzilla 13815), and we can thus revert the low_latency pty hack
(commit 3a54297478e6578f96fd54bf4daa1751130aca86: "pty: quickfix for the
pty ENXIO timing problems").
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[ Modified to do the tty_flush_to_ldisc() inside input_available_p() so
that it triggers for both read and poll() - Linus]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This also makes close stall in the normal case which is apparently
needed to fix emacs
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT
This will make hardirq.h inclusion cheaper for every PREEMPT=n config
(which includes allmodconfig/allyesconfig, BTW)
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes the ppp problems and various other issues with call locking
caused by one side of a pty called in one locking context trying to match
another with differing rules on the other side. We also get a big slack
space to work with that means we can bury the flow control deadlock case
for any conceivable real world situation.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The pty code has always been buggy on its ldisc handling. The recent
changes made the window for the race much bigger. Pending fixing it
properly which is not at all trivial, at least make the race small again so
we don't disrupt other dev work.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are several pretty much unfixable races in the old ldisc code, especially
with respect to pty behaviour and also to hangup. It's easier to rewrite the
code than simply try and patch it up.
This patch
- splits the ldisc from the tty (so we will be able to refcount it more cleanly
later)
- introduces a mutex lock for ldisc changing on an active device
- fixes the complete mess that hangup caused
- implements hopefully correct setldisc/close/hangup locking
There are still some problems around pty pairs that have always been there but
at least it is now possible to understand the code and fix further problems.
This fixes the following known bugs
- hang up can leak ldisc references
- hang up may not call open/close on ldisc in a matched way
- pty/tty pairs can deadlock during an ldisc change
- reading the ldisc proc files can cause every ldisc to be loaded
and probably a few other of the mysterious ldisc race reports.
I'm sure it also adds the odd new one.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We fixed the globals, so now fix the comment
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The pty changes and updates for window sizing forgot to correct the
kerneldoc
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Building an allnoconfig kernel, sparse asked whether these could be
static, so I checked, and they are only used in the file where they are
declared.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The write wakeup is done anyway for the poll while DO_WRITE_WAKUP is
cleared, set and managed by the ldisc layer and is no business of the pty
code.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have special case logic for resizing pty/tty pairs. We also have a per
driver resize method so for the pty case we should use it.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We need both termios and termios_locked so allocate them as one
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The updating and moving around of the pty code added a bug where both the
helper and caller free the main tty struct (the pty driver must free the
o_tty pair itself however).
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We've done the heavy lifting now its time to mop up a bit
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pass-in 'inode' or 'tty' parameter to devpts interfaces. With multiple
devpts instances, these parameters will be used in subsequent patches
to identify the instance of devpts mounted. The parameters also help
simplify devpts implementation.
Changelog[v3]:
- minor changes due to merge with ttydev updates
- rename parameters to emphasize they are ptmx or pts inodes
- pass-in tty_struct * to devpts_pty_kill() (this will help
cleanup the get_node() call in a subsequent patch)
Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The majority of the remaining init_dev code is pty special cases. We
refactor this code into the driver->install method.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Original suggestion and proposal from Sukadev Bhattiprolu.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have the lookup operation abstracted which is nice for pty cleanup but
we really want to abstract the add/remove entries as well so that we can
pull the pty code out of the tty core and create a clear defined interface
for the tty driver table.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix up the naming, style and extract some bits of code into the driver
specific code
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Carry on pushing code out of tty_io when it belongs to other drivers. I'm
not 100% happy with some of this and it will be worth revisiting some of the
exports later when the restructuring work is done.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Right now there are various drivers that try to use tty->count to know when
they get the final close. Aristeau Rozanski showed while debugging the vt
sysfs race that this isn't entirely safe.
Instead of driver side tricks to work around this introduce a shutdown which
is called when the tty is being destructed. This also means that the shutdown
method is tied into the refcounting.
Use this to rework the console close/sysfs logic.
Remove lots of special case code from the tty core code. The pty code can now
have a shutdown() method that replaces the special case hackery in the tree
free up paths.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
We are about to change the tty layer to avoid keeping private copies of all
the methods in each tty. We have to update the pty layer first as it
currently patches the ioctl method according to the tty type. Use multiple
tty operations sets instead.
Signed-off-by: Alan Cox <alan@redhat.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Push the BKL down into the line disciplines
- Switch the tty layer to unlocked_ioctl
- Introduce a new ctrl_lock spin lock for the control bits
- Eliminate much of the lock_kernel use in n_tty
- Prepare to (but don't yet) call the drivers with the lock dropped
on the paths that historically held the lock
BKL now primarily protects open/close/ldisc change in the tty layer
[jirislaby@gmail.com: a couple of fixes]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Instead of having a bunch of ifdefs in sysctl.c move all of the pty sysctl
logic into drivers/char/pty.c
As well as cleaning up the logic this prevents sysctl_check_table from
complaining that the root table has a NULL data pointer on something with
generic methods.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
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>
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>
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/devfs-2.6: (22 commits)
[PATCH] devfs: Remove it from the feature_removal.txt file
[PATCH] devfs: Last little devfs cleanups throughout the kernel tree.
[PATCH] devfs: Rename TTY_DRIVER_NO_DEVFS to TTY_DRIVER_DYNAMIC_DEV
[PATCH] devfs: Remove the tty_driver devfs_name field as it's no longer needed
[PATCH] devfs: Remove the line_driver devfs_name field as it's no longer needed
[PATCH] devfs: Remove the videodevice devfs_name field as it's no longer needed
[PATCH] devfs: Remove the gendisk devfs_name field as it's no longer needed
[PATCH] devfs: Remove the miscdevice devfs_name field as it's no longer needed
[PATCH] devfs: Remove the devfs_fs_kernel.h file from the tree
[PATCH] devfs: Remove devfs_remove() function from the kernel tree
[PATCH] devfs: Remove devfs_mk_cdev() function from the kernel tree
[PATCH] devfs: Remove devfs_mk_bdev() function from the kernel tree
[PATCH] devfs: Remove devfs_mk_symlink() function from the kernel tree
[PATCH] devfs: Remove devfs_mk_dir() function from the kernel tree
[PATCH] devfs: Remove devfs_*_tape() functions from the kernel tree
[PATCH] devfs: Remove devfs support from the sound subsystem
[PATCH] devfs: Remove devfs support from the ide subsystem.
[PATCH] devfs: Remove devfs support from the serial subsystem
[PATCH] devfs: Remove devfs from the init code
[PATCH] devfs: Remove devfs from the partition code
...
Remove TTY_DONT_FLIP tty flag. This flag was introduced in 2.1.X kernels
to prevent the N_TTY line discipline functions read_chan() and
n_tty_receive_buf() from running at the same time. 2.2.15 introduced
tty->read_lock to protect access to the N_TTY read buffer, which is the
only state requiring protection between these two functions.
The current TTY_DONT_FLIP implementation is broken for SMP, and is not
universally honored by drivers that send data directly to the line
discipline receive_buf function.
Because TTY_DONT_FLIP is not necessary, is broken in implementation, and is
not universally honored, it is removed.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I've always found this flag confusing. Now that devfs is no longer around, it
has been renamed, and the documentation for when this flag should be used has
been updated.
Also fixes all drivers that use this flag.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Arnd Bergmann