Revert "hvc_console: display printk messages on console."

This reverts commit 361162459f62dc0826b82c9690a741a940f457f0.

It causes an infinite loop when booting Linux under Xen, as so:

  [    2.382984] console [hvc0] enabled
  [    2.382984] console [hvc0] enabled
  [    2.382984] console [hvc0] enabled
  ...

as reported by Konrad Rzeszutek Wilk.  And Rusty reports the same for
lguest.  He goes on to say:

   "This is not a concurrency problem: the issue seems to be that
    calling register_console() twice on the same struct console is a bad
    idea."

and Greg says he'll fix it up properly at some point later. Revert for now.

Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reported-by: Rusty Russell <rusty@ozlabs.org>
Requested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Miche Baker-Harvey <miche@google.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 6 deletions

diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
index 7430bc3c8d53..b6b2d18fa38d 100644
--- a/drivers/tty/hvc/hvc_console.c
+++ b/drivers/tty/hvc/hvc_console.c
@@ -852,7 +852,7 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
          * find index to use:
          * see if this vterm id matches one registered for console.
          */
-        for (i = 0; i < MAX_NR_HVC_CONSOLES; i++)
+        for (i=0; i < MAX_NR_HVC_CONSOLES; i++)
                 if (vtermnos[i] == hp->vtermno &&
                     cons_ops[i] == hp->ops)
                         break;
@@ -862,13 +862,9 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
                 i = ++last_hvc;
 
         hp->index = i;
-        hvc_console.index = i;
-        vtermnos[i] = vtermno;
-        cons_ops[i] = ops;
 
         list_add_tail(&(hp->next), &hvc_structs);
         spin_unlock(&hvc_structs_lock);
-        register_console(&hvc_console);
 
         return hp;
 }
@@ -879,7 +875,6 @@ int hvc_remove(struct hvc_struct *hp)
         unsigned long flags;
         struct tty_struct *tty;
 
-        unregister_console(&hvc_console);
         spin_lock_irqsave(&hp->lock, flags);
         tty = tty_kref_get(hp->tty);