linux.git/drivers/char/hvc_console.c, branch master

tty: move hvc drivers to drivers/tty/hvc/

2011-01-13T20:03:00+00:00

As requested by Arnd Bergmann, the hvc drivers are now
moved to the drivers/tty/hvc/ directory.  The virtio_console.c driver
was also moved, as it required the hvc_console.h file to be able to be
built, and it really is a hvc driver.

Cc: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

drivers/char/hvc_console.c: remove unneeded __set_current_state(TASK_RUNNING)

2010-10-28T01:03:14+00:00

This doesn't do anything.

Cc: Timur Tabi 
Cc: Benjamin Herrenschmidt 
Cc: Amit Shah 
Cc: Greg Kroah-Hartman 
Cc: Kumar Gala 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Input: sysrq - drop tty argument form handle_sysrq()

2010-08-21T07:34:45+00:00

Sysrq operations do not accept tty argument anymore so no need to pass
it to us.

[Stephen Rothwell : fix build breakage in drm code
 caused by sysrq using bool but not including linux/types.h]

[Sachin Sant : fix build breakage in s390 keyboadr
 driver]

Acked-by: Alan Cox 
Acked-by: Jason Wessel 
Acked-by: Greg Kroah-Hartman 
Signed-off-by: Dmitry Torokhov

hvc_console: use "*_console" nomenclature to avoid modpost warning.

2010-07-09T01:28:24+00:00

The use of "hvc_con_driver" as the name for a file-static "struct
console" with a ".setup" field pointing to an __init function causes
a modpost warning, since a non-initdata structure points to init code.
Using "hvc_console" as the name triggers the hacky "*_console"
workaround in modpost to silence the warning, and is the same thing
that most of the other console drivers already do.

I made the same change in hvsi.c since I happened to notice it was
likely to suffer from the same problem.

Signed-off-by: Chris Metcalf 
Signed-off-by: Benjamin Herrenschmidt

hvc_console: Fix race between hvc_close and hvc_remove

2010-04-08T00:16:20+00:00

I don't claim to understand the tty layer, but it seems like hvc_open and
hvc_close should be balanced in their kref reference counting.

Right now we get a kref every call to hvc_open:

        if (hp->count++ > 0) {
                tty_kref_get(tty); <----- here
                spin_unlock_irqrestore(&hp->lock, flags);
                hvc_kick();
                return 0;
        } /* else count == 0 */

        tty->driver_data = hp;

        hp->tty = tty_kref_get(tty); <------ or here if hp->count was 0

But hvc_close has:

        tty_kref_get(tty);

        if (--hp->count == 0) {
...
                /* Put the ref obtained in hvc_open() */
                tty_kref_put(tty);
...
        }

        tty_kref_put(tty);

Since the outside kref get/put balance we only do a single kref_put when
count reaches 0.

The patch below changes things to call tty_kref_put once for every
hvc_close call, and with that my machine boots fine.

Signed-off-by: Anton Blanchard 
Acked-by: Amit Shah 
Signed-off-by: Rusty Russell

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30T13:02:32+00:00

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 
Guess-its-ok-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Lee Schermerhorn

hvc_console: Fix race between hvc_close and hvc_remove

2010-03-19T14:17:54+00:00

Alan pointed out a race in the code where hvc_remove is invoked. The
recent virtio_console work is the first user of hvc_remove().

Alan describes it thus:

The hvc_console assumes that a close and remove call can't occur at the
same time.

In addition tty_hangup(tty) is problematic as tty_hangup is asynchronous
itself....

So this can happen

        hvc_close                               hvc_remove
        hung up ? - no
                                                lock
                                                tty = hp->tty
                                                unlock
        lock
        hp->tty = NULL
        unlock
        notify del
        kref_put the hvc struct
        close completes
        tty is destroyed
                                                tty_hangup dead tty
                                                tty->ops will be NULL
                                                NULL->...

This patch adds some tty krefs and also converts to using tty_vhangup().

Reported-by: Alan Cox 
Signed-off-by: Amit Shah 
CC: Alan Cox 
CC: linuxppc-dev@ozlabs.org
CC: Rusty Russell 
Signed-off-by: Greg Kroah-Hartman

hvc_console: fix test on unsigned in hvc_console_print()

2010-03-02T22:43:13+00:00

vtermnos[] is unsigned, so this test was wrong.

Signed-off-by: Roel Kluin 
Cc: Benjamin Herrenschmidt 
Cc: Hendrik Brueckner 
Cc: Christian Borntraeger 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

hvc_console: Remove __devinit annotation from hvc_alloc

2010-02-03T06:39:49+00:00

Virtio consoles can be hotplugged, so hvc_alloc gets called from
multiple sites: from the initial probe() routine as well as later on
from workqueue handlers which aren't __devinit code.

So, drop the __devinit annotation for hvc_alloc.

Signed-off-by: Amit Shah 
Cc: linuxppc-dev@ozlabs.org
Signed-off-by: Benjamin Herrenschmidt

hvc_console: Make the ops pointer const.

2010-02-03T06:39:49+00:00

This is nicer for modern R/O protection.  And noone needs it non-const, so
constify the callers as well.

Signed-off-by: Rusty Russell 
Signed-off-by: Amit Shah 
To: Christian Borntraeger 
Cc: linuxppc-dev@ozlabs.org
Signed-off-by: Benjamin Herrenschmidt