[PULL] virtio console fixes

[PULL] virtio console fixes

[Rusty Russell]

The following changes since commit 48de8cb7847d040c8892701c1ff3c55eff1f46b4:
  Linus Torvalds (1):
        Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/.../tip/linux-2.6-tip

are available in the git repository at:

  ssh://master.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus.git master

Amit Shah (1):
      MAINTAINERS: Put the virtio-console entry in correct alphabetical order

Anton Blanchard (1):
      hvc_console: Fix race between hvc_close and hvc_remove

François Diakhaté (1):
      virtio: console: Fix early_put_chars usage

Michael S. Tsirkin (1):
      virtio: disable multiport console support.

Rusty Russell (1):
      virtio: console makes incorrect assumption about virtio API

 MAINTAINERS                    |   13 ++++----
 drivers/char/hvc_console.c     |    4 --
 drivers/char/virtio_console.c  |   65 +++++++++++++++++++++++++++++-----------
 include/linux/virtio_console.h |   23 --------------
 4 files changed, 54 insertions(+), 51 deletions(-)

commit 9a82446bd269b130a9ac270e720e65c3843d4d0c
Author: Amit Shah <amit.shah@redhat.com>
Date:   Tue Mar 23 18:23:09 2010 +0530

    MAINTAINERS: Put the virtio-console entry in correct alphabetical order
    
    Move around the entry for virtio-console to keep the file sorted.
    
    Signed-off-by: Amit Shah <amit.shah@redhat.com>
    Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

 MAINTAINERS |   13 +++++++------
 1 files changed, 7 insertions(+), 6 deletions(-)

commit 162a689a13ed61c0752726edb75427b2cd4186c1
Author: François Diakhaté <fdiakh@gmail.com>
Date:   Tue Mar 23 18:23:15 2010 +0530

    virtio: console: Fix early_put_chars usage
    
    Currently early_put_chars is not used by virtio_console because it can
    only be used once a port has been found, at which point it's too late
    because it is no longer needed. This patch should fix it.
    
    Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
    Signed-off-by: Amit Shah <amit.shah@redhat.com>
    Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

 drivers/char/virtio_console.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

commit 9ff4cfab82d27e9fda72315f911bbaa9516e04bc
Author: Rusty Russell <rusty@rustcorp.com.au>
Date:   Thu Apr 8 09:46:16 2010 -0600

    virtio: console makes incorrect assumption about virtio API
    
    The get_buf() API sets the second arg to the number of bytes *written*
    by the other side; in this case it should be zero as these are output buffers.
    
    lguest gets this right (obviously kvm's console doesn't), resulting in
    continual buildup of console writes.
    
    Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
    Acked-by: Amit Shah <amit.shah@redhat.com>

 drivers/char/virtio_console.c |   10 +++-------
 1 files changed, 3 insertions(+), 7 deletions(-)

commit b7a413015d2986edf020fba765c906cc9cbcbfc9
Author: Michael S. Tsirkin <mst@redhat.com>
Date:   Wed Mar 31 21:56:42 2010 +0300

    virtio: disable multiport console support.
    
    Move MULTIPORT feature and related config changes
    out of exported headers, and disable the feature
    at runtime.
    
    At this point, it seems less risky to keep code around
    until we can enable it than rip it out completely.
    
    Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
    Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

 drivers/char/virtio_console.c  |   49 +++++++++++++++++++++++++++++++++------
 include/linux/virtio_console.h |   23 ------------------
 2 files changed, 41 insertions(+), 31 deletions(-)

commit 320718ee074acce5ffced6506cb51af1388942aa
Author: Anton Blanchard <anton@samba.org>
Date:   Tue Apr 6 21:42:38 2010 +1000

    hvc_console: Fix race between hvc_close and hvc_remove
    
    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 <anton@samba.org>
    Acked-by: Amit Shah <amit.shah@redhat.com>
    Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

 drivers/char/hvc_console.c |    4 ----
 1 files changed, 0 insertions(+), 4 deletions(-)