tty: The big operations rework
- Operations are now a shared const function block as with most other Linux
objects
- Introduce wrappers for some optional functions to get consistent behaviour
- Wrap put_char which used to be patched by the tty layer
- Document which functions are needed/optional
- Make put_char report success/fail
- Cache the driver->ops pointer in the tty as tty->ops
- Remove various surplus lock calls we no longer need
- Remove proc_write method as noted by Alexey Dobriyan
- Introduce some missing sanity checks where certain driver/ldisc
combinations would oops as they didn't check needed methods were present
[akpm@linux-foundation.org: fix fs/compat_ioctl.c build]
[akpm@linux-foundation.org: fix isicom]
[akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build]
[akpm@linux-foundation.org: fix kgdb]
Signed-off-by: Alan Cox <alan@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/net/slip.c b/drivers/net/slip.c
index 5a55ede..84af68f 100644
--- a/drivers/net/slip.c
+++ b/drivers/net/slip.c
@@ -396,14 +396,14 @@
/* Order of next two lines is *very* important.
* When we are sending a little amount of data,
- * the transfer may be completed inside driver.write()
+ * the transfer may be completed inside the ops->write()
* routine, because it's running with interrupts enabled.
* In this case we *never* got WRITE_WAKEUP event,
* if we did not request it before write operation.
* 14 Oct 1994 Dmitry Gorodchanin.
*/
sl->tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
- actual = sl->tty->driver->write(sl->tty, sl->xbuff, count);
+ actual = sl->tty->ops->write(sl->tty, sl->xbuff, count);
#ifdef SL_CHECK_TRANSMIT
sl->dev->trans_start = jiffies;
#endif
@@ -437,7 +437,7 @@
return;
}
- actual = tty->driver->write(tty, sl->xhead, sl->xleft);
+ actual = tty->ops->write(tty, sl->xhead, sl->xleft);
sl->xleft -= actual;
sl->xhead += actual;
}
@@ -462,7 +462,7 @@
}
printk(KERN_WARNING "%s: transmit timed out, %s?\n",
dev->name,
- (sl->tty->driver->chars_in_buffer(sl->tty) || sl->xleft) ?
+ (tty_chars_in_buffer(sl->tty) || sl->xleft) ?
"bad line quality" : "driver error");
sl->xleft = 0;
sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
@@ -830,6 +830,9 @@
if (!capable(CAP_NET_ADMIN))
return -EPERM;
+ if (tty->ops->write == NULL)
+ return -EOPNOTSUPP;
+
/* RTnetlink lock is misused here to serialize concurrent
opens of slip channels. There are better ways, but it is
the simplest one.
@@ -1432,7 +1435,7 @@
/* put END into tty queue. Is it right ??? */
if (!netif_queue_stopped(sl->dev)) {
/* if device busy no outfill */
- sl->tty->driver->write(sl->tty, &s, 1);
+ sl->tty->ops->write(sl->tty, &s, 1);
}
} else
set_bit(SLF_OUTWAIT, &sl->flags);
