If the host is slow in reading data or doesn't read data at all,
blocking write calls not only blocked the program that called write()
but the entire guest itself.
To overcome this, let's not block till the host signals it has given
back the virtio ring element we passed it. Instead, send the buffer to
the host and return to userspace. This operation then becomes similar
to how non-blocking writes work, so let's use the existing code for this
path as well.
This code change also ensures blocking write calls do get blocked if
there's not enough room in the virtio ring as well as they don't return
-EAGAIN to userspace.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
CC: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After d9e1b6c450 ("ipmi: fix ACPI detection with regspacing") we get
[ 11.026326] ipmi_si: probing via ACPI
[ 11.030019] ipmi_si 00:09: (null) regsize 1 spacing 1 irq 0
[ 11.035594] ipmi_si: Adding ACPI-specified kcs state machine
on an old system with only one range for ipmi kcs range.
Try to fix it by adding another res pointer.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These devices don't do any writeback but their device inodes still can get
dirty so mark bdi appropriately so that bdi code does the right thing and files
inodes to lists of bdi carrying the device inodes.
Cc: stable@kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
A userspace could submit a buffer with 0 length to be written to the
host. Prevent such a situation.
This was not needed previously, but recent changes in the way write()
works exposed this condition to trigger a virtqueue event to the host,
causing a NULL buffer to be sent across.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
CC: stable@kernel.org
I found this while working on a Linux agent for spice, the symptom I was
seeing was select blocking on the spice vdagent virtio serial port even
though there were messages queued up there.
virtio_console's port_fops_poll checks port->inbuf != NULL to determine
if read won't block. However if an application reads enough bytes from
inbuf through port_fops_read, to empty the current port->inbuf,
port->inbuf will be NULL even though there may be buffers left in the
virtqueue.
This causes poll() to block even though there is data to be read,
this patch fixes this by using will_read_block(port) instead of the
port->inbuf != NULL check.
Signed-off-By: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
There is a second revision of B43 (a desktop gen4 part) floating around,
functionally equivalent to the original B43, so simply add the new
PCI-IDs.
Bugzilla: https://bugs.freedesktop.org/show_bugs.cgi?id=30221
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org
New pci ids for GT2 and GT2+ on desktop and mobile sandybridge,
and graphics device ids for server sandybridge. Also rename original
ids string to reflect GT1 version.
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Sandybridge GTT has new cache control bits in PTE, which controls
graphics page cache in LLC or LLC/MLC, so we need to extend the mask
function to respect the new bits.
And set cache control to always LLC only by default on Gen6.
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
It should shift bit 39-32 into pte's bit 11-4.
Reported-by:Takashi Iwai <tiwai@suse.de>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Make sure we always detect when we fail to correctly allocate the Isoch
Flush Page and print an error to warn the user about the likely memory
corruption that will result in invalid rendering or worse.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: stable@kernel.org
I found a bug "by chance" in drivers/char/tty_io.c
I mean "by chance" because I was just reading the code of the
tty_find_polling_driver() to make a new tty_find_by_name() function.
In tty_find_polling_driver() the driver actually test "tty_line <=
p->num" while num refers to the number of struct tty_struct pointers
allocated for the p->ttys (p is a tty_driver), and tty_line is scanned
in a tty name, which can be for example ttyS2. Then tty_line equals 2.
And if p->num is 2, we have only p->ttys[0] and p->ttys[1], but no
p->ttys[2].
This is actually unharmful, for tty_find_polling_driver() is used only
in drivers/serial/kgdboc.c, and there's a test over there to find a
console with a matching index, which will never happen.
This is still a bug anyway.
Signed-off-by: Nathael Pajani <nathael.pajani@ed3l.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
After 02f0777a0d "vc_origin" is no
longer reset to the screen buffer before calling the con_init() hook
of the new console driver.
If the old driver wasn't using a fixed scanout buffer (e.g. the case
of vgacon) "vc_origin" may be a pointer to a VRAM location, and its
contents aren't guaranteed to be preserved after calling con_deinit()
on the old driver and con_init() on the new driver, i.e. the
subsequent console resize may fill the framebuffer with garbage.
It can be reproduced in the transition from vgacon to the nouveau
framebuffer driver: in that case the legacy VGA aperture "vc_origin"
points to becomes unreadable after fbcon_init().
This patch reverts the mentioned commit. To avoid the problem it
intended to fix, stop using "vc_scr_end" in vc_do_resize() to
calculate how many rows we have to copy (actually the code looks
simpler this way without the help of "vc_scr_end").
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Cc: qiaochong <qiaochong@loongson.cn>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The KIOCSOUND and KDMKTONE ioctls are based on the CLOCK_TICK_RATE,
which is architecture and sometimes configuration specific.
In practice, most user applications assume that it is actually defined
as the i8253 PIT base clock of 1193182 Hz, which is true on some
architectures but not on others.
This patch makes the vt code use the PIT frequency on all
architectures, which is much more well-defined. It will change the
behavior of user applications sending the beep ioctl on all
architectures that define CLOCK_TICK_RATE different from
PIT_TICK_RATE.
The original breakage was introduced in commit bcc8ca099 "Adapt
drivers/char/vt_ioctl.c to non-x86". Hopefully, reverting this change
will make the frequency correct in more cases than it will make it
incorrect.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
There is a path which still holds its mutex here.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This path needs a mutex_unlock(). This is stuff from the bkl to mutex
transition.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
copy_to_user() returns the number of bytes remaining but we want to return
a negative error code on errors.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Cc: "Michael H. Warfield" <mhw@wittsend.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We don't pass NULL tty pointers to the close function, and anyway we
already dereferenced it at this point. This check can be removed.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Cc: "Michael H. Warfield" <mhw@wittsend.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Sysrq operations do not accept tty argument anymore so no need to pass
it to us.
[Stephen Rothwell <sfr@canb.auug.org.au>: fix build breakage in drm code
caused by sysrq using bool but not including linux/types.h]
[Sachin Sant <sachinp@in.ibm.com>: fix build breakage in s390 keyboadr
driver]
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Noone is using tty argument so let's get rid of it.
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
tty: fix fu_list abuse
tty code abuses fu_list, which causes a bug in remount,ro handling.
If a tty device node is opened on a filesystem, then the last link to the inode
removed, the filesystem will be allowed to be remounted readonly. This is
because fs_may_remount_ro does not find the 0 link tty inode on the file sb
list (because the tty code incorrectly removed it to use for its own purpose).
This can result in a filesystem with errors after it is marked "clean".
Taking idea from Christoph's initial patch, allocate a tty private struct
at file->private_data and put our required list fields in there, linking
file and tty. This makes tty nodes behave the same way as other device nodes
and avoid meddling with the vfs, and avoids this bug.
The error handling is not trivial in the tty code, so for this bugfix, I take
the simple approach of using __GFP_NOFAIL and don't worry about memory errors.
This is not a problem because our allocator doesn't fail small allocs as a rule
anyway. So proper error handling is left as an exercise for tty hackers.
[ Arguably filesystem's device inode would ideally be divorced from the
driver's pseudo inode when it is opened, but in practice it's not clear whether
that will ever be worth implementing. ]
Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs: cleanup files_lock locking
Lock tty_files with a new spinlock, tty_files_lock; provide helpers to
manipulate the per-sb files list; unexport the files_lock spinlock.
Cc: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This patch fixes missing includes from a number of .c files because
the code (wrongfully) depended on prom.h including them. The include
of linux/of_address.h was removed in microblaze prom.h in commit
"of/address: Clean up function declarations" (sha1 id 22ae782f8), but
not fixed in some callers. This patch fixes them up.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Michal Simek <monstr@monstr.eu>
Commit b45cfba4e9 (vt,console,kdb:
implement atomic console enter/leave functions) introduced the ability
to atomically change the console mode with kernel mode setting but did
not preserve the state of the console_blanked variable.
The console_blanked variable must be restored when executing the
con_debug_leave() or further kernel mode set changes (such as using
chvt X) will fail to correctly set the state of console.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
CC: Andrew Morton <akpm@linux-foundation.org>
Fix the following new sparse warnings in vt.c introduced by the commit
b45cfba4e9 (vt,console,kdb: implement
atomic console enter/leave functions):
drivers/char/vt.c:197:5: warning: symbol 'saved_fg_console' was not declared. Should it be static?
drivers/char/vt.c:198:5: warning: symbol 'saved_last_console' was not declared. Should it be static?
drivers/char/vt.c:199:5: warning: symbol 'saved_want_console' was not declared. Should it be static?
drivers/char/vt.c:200:5: warning: symbol 'saved_vc_mode' was not declared. Should it be static?
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
CC: Andrew Morton <akpm@linux-foundation.org>
Fix kconfig dependency warning for PC8736x_GPIO by restricting it to
X86_32.
warning: (SCx200_GPIO && SCx200 || PC8736x_GPIO && X86) selects NSC_GPIO which has unmet direct dependencies (X86_32)
NSC_GPIO is X86_32 only. The other driver (SCx200_GPIO) that selects
NSC_GPIO is X86_32 only (indirectly, since SCx200 depends on X86_32), so
limit this driver also.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Jordan Crouse <jordan.crouse@amd.com>
Cc: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are different types of a fifo which can not handled in C without a
lot of overhead. So i decided to write the API as a set of macros, which
is the only way to do a kind of template meta programming without C++.
This macros handles the different types of fifos in a transparent way.
There are a lot of benefits:
- Compile time handling of the different fifo types
- Better performance (a save put or get of an integer does only generate
9 assembly instructions on a x86)
- Type save
- Cleaner interface, the additional kfifo_..._rec() functions are gone
- Easier to use
- Less error prone
- Different types of fifos: it is now possible to define a int fifo or
any other type. See below for an example.
- Smaller footprint for none byte type fifos
- No need of creating a second hidden variable, like in the old DEFINE_KFIFO
The API was not changed.
There are now real in place fifos where the data space is a part of the
structure. The fifo needs now 20 byte plus the fifo space. Dynamic
assigned or allocated create a little bit more code.
Most of the macros code will be optimized away and simple generate a
function call. Only the really small one generates inline code.
Additionally you can now create fifos for any data type, not only the
"unsigned char" byte streamed fifos.
There is also a new kfifo_put and kfifo_get function, to handle a single
element in a fifo. This macros generates inline code, which is lit bit
larger but faster.
I know that this kind of macros are very sophisticated and not easy to
maintain. But i have all tested and it works as expected. I analyzed the
output of the compiler and for the x86 the code is as good as hand written
assembler code. For the byte stream fifo the generate code is exact the
same as with the current kfifo implementation. For all other types of
fifos the code is smaller before, because the interface is easier to use.
The main goal was to provide an API which is very intuitive, save and easy
to use. So linux will get now a powerful fifo API which provides all what
a developer needs. This will save in the future a lot of kernel space,
since there is no need to write an own implementation. Most of the device
driver developers need a fifo, and also deep kernel development will gain
benefit from this API.
Here are the results of the text section usage:
Example 1:
kfifo_put/_get kfifo_in/out current kfifo
dynamic allocated 0x000002a8 0x00000291 0x00000299
in place 0x00000291 0x0000026e 0x00000273
kfifo.c new old
text section size 0x00000be5 0x000008b2
As you can see, kfifo_put/kfifo_get creates a little bit more code than
kfifo_in/kfifo_out, but it is much faster (the code is inline).
The code is complete hand crafted and optimized. The text section size is
as small as possible. You get all the fifo handling in only 3 kb. This
includes type safe fix size records, dynamic records and DMA handling.
This should be the final version. All requested features are implemented.
Note: Most features of this API doesn't have any users. All functions
which are not used in the next 9 months will be removed. So, please adapt
your drivers and other sources as soon as possible to the new API and post
it.
This are the features which are currently not used in the kernel:
kfifo_to_user()
kfifo_from_user()
kfifo_dma_....() macros
kfifo_esize()
kfifo_recsize()
kfifo_put()
kfifo_get()
The fixed size record elements, exclude "unsigned char" fifo's and the
variable size records fifo's
This patch:
User of the kernel fifo should never bypass the API and directly access
the fifo structure. Otherwise it will be very hard to maintain the API.
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a spin_unlock_irqrestore missing on the error path. Converting the
return to break leads to the spin_unlock_irqrestore at the end of the
function.
The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@@
expression E1;
@@
* spin_lock_irqsave(E1,...);
<+... when != E1
if (...) {
... when != E1
* return ...;
}
...+>
* spin_unlock_irqrestore(E1,...);
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Print out the reg spacing and size for spmi and smbios so BIOS developers
can make them consistent.
Also remove extra PFX on the duplicating path.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Corey Minyard <minyard@acm.org>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Myron Stowe <myron.stowe@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Free the temporary info struct when we have duplicated ones.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Corey Minyard <minyard@acm.org>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Myron Stowe <myron.stowe@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix a warning message generated by GCC, and also updates a web address
pointing to a pdf containing information.
CC [M] drivers/char/ipmi/ipmi_si_intf.o
drivers/char/ipmi/ipmi_si_intf.c: In function 'try_init_spmi':
drivers/char/ipmi/ipmi_si_intf.c:2016:8: warning: variable 'addr_space' set but not used
Signed-off-by: Sergey V. <sftp.mtuci@gmail.com>
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Acked-by: Corey Minyard <minyard@acm.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is one of the most interesting users of module parameters in the
tree, so weaning it off the old-style non-const module_param_call
scheme is a useful exercise.
I was confused by set_param_int/get_param_int (vs. the normal
param_set_int and param_get_int), so I renamed set_param_int to
set_param_timeout, and re-used param_get_int directly instead of
get_param_int. I also implemented param_check_wdog_ifnum and
param_check_timeout, so now the ifnum_to_use and timeout/pretimeout
parameters can just use plain module_param().
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Corey Minyard <minyard@acm.org>
Cc: openipmi-developer@lists.sourceforge.net
Today's next 20091117 build failed on s390 with
drivers/char/hvc_iucv.c:1331: error: 'param_ops_vmidfilter' undeclared here (not in a function)
make[2]: *** [drivers/char/hvc_iucv.o] Error 1
Most probably caused by commit 684a6d340b8a5767db4670031b0f39455346018a
(param:param_ops) which introduced a param_ops structure.
The following compile tested patch adds a param_ops structure for hvc_iucv.
Signed-off-by: Sachin Sant <sachinp@in.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Tested-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Sorry, one more fix, this one depends on the other, so this is rather 2/2.
--
tty->driver_data is used all over the code, but never set. This
results in oopses like:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000130
IP: [<ffffffff814a0040>] mutex_lock+0x10/0x40
...
Pid: 2157, comm: modem-manager Not tainted 2.6.34.1-0.1-desktop #1 2768DR7/2768DR7
RIP: 0010:[<ffffffff814a0040>] [<ffffffff814a0040>] mutex_lock+0x10/0x40
RSP: 0018:ffff88007b16fa50 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000130 RCX: 0000000000000003
RDX: 0000000000000003 RSI: 0000000000000286 RDI: 0000000000000130
RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000130
R13: 0000000000000001 R14: 0000000000000000 R15: ffff88007b16feb4
...
Call Trace:
[<ffffffffa077690d>] ntty_write_room+0x4d/0x90 [nozomi]
...
Set tty->driver_data to the computed port in .install to not recompute it in
every place where needed. Switch .open to use driver_data too.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@kernel.org> [.34, .35]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Currently ntty_install omits to increment tty count and we get the
following warnings:
Warning: dev (noz2) tty->count(0) != #fd's(1) in tty_open
So to fix that, add one tty->count++ there.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@kernel.org> [.34, .35]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
mxser_transmit_chars(tty, port) is called only from mxser_interrupt().
NULL check is performed in mxser_interrupt() so it is redundant here.
Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
Acked-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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>
Most tty drivers may block while opening a device.
Since this possibly depends on another thread
closing it first and both threads may need the BTM,
we need to release it here.
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>
The tty locking now follows the rules for mutexes, so
we can replace the BKL usage with a new subsystem
wide mutex.
Using a regular mutex here will change the behaviour
when blocked on the BTM from spinning to sleeping,
but that should not be visible to the user.
Using the mutex also means that all the BTM is now
covered by lockdep.
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 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>
Some wait_until_sent versions require the big
tty mutex, others don't and some callers of
wait_until_sent already hold it while other don't.
That leads to recursive use of the BTM in these
functions, which we're trying to get rid of.
This turns all cleans up the locking there so
that the driver's wait_until_sent function
never takes the BTM itself if it is already
called with that lock held.
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>
We need to release the BTM in paste_selection() when
sleeping in tty_ldisc_ref_wait to avoid deadlocks
with tty_ldisc_enable.
In tty_set_ldisc, we now always grab the BTM before
taking the ldisc_mutex in order to avoid AB-BA
deadlocks between the two.
tty_ldisc_halt potentially blocks on a workqueue
function that takes the BTM, so we must release
the BTM before calling it.
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>
Calling wait_event_interruptible implicitly
releases the BKL when it sleeps, but we need
to do this explcitly when we have converted
it to a mutex.
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 takes all the tty references through the expected interface points so
we can refcount them.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Amit Shah