[PATCH] tty buffering stall fix
Prevent stalled processing of received data when a driver allocates tty
buffer space but does not immediately follow the allocation with more data
and a call to schedule receive tty processing. (example: hvc_console) This
bug was introduced by the first locking patch for the new tty buffering.
Signed-off-by: Paul Fulghum <paulkf@microgate.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/kbd_kern.h b/include/linux/kbd_kern.h
index 3aed373..e87c32a 100644
--- a/include/linux/kbd_kern.h
+++ b/include/linux/kbd_kern.h
@@ -153,8 +153,10 @@
{
unsigned long flags;
spin_lock_irqsave(&t->buf.lock, flags);
- if (t->buf.tail != NULL)
+ if (t->buf.tail != NULL) {
t->buf.tail->active = 0;
+ t->buf.tail->commit = t->buf.tail->used;
+ }
spin_unlock_irqrestore(&t->buf.lock, flags);
schedule_work(&t->buf.work);
}
diff --git a/include/linux/tty.h b/include/linux/tty.h
index a7bd3b4..f45cd74 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -58,6 +58,8 @@
int used;
int size;
int active;
+ int commit;
+ int read;
/* Data points here */
unsigned long data[0];
};
diff --git a/include/linux/tty_flip.h b/include/linux/tty_flip.h
index 82961eb..222faf9 100644
--- a/include/linux/tty_flip.h
+++ b/include/linux/tty_flip.h
@@ -29,8 +29,10 @@
{
unsigned long flags;
spin_lock_irqsave(&tty->buf.lock, flags);
- if (tty->buf.tail != NULL)
+ if (tty->buf.tail != NULL) {
tty->buf.tail->active = 0;
+ tty->buf.tail->commit = tty->buf.tail->used;
+ }
spin_unlock_irqrestore(&tty->buf.lock, flags);
schedule_delayed_work(&tty->buf.work, 1);
}