workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted

apply_wqattrs_commit() updates node_nr_active->max unconditionally.
wq->node_nr_active[] is only allocated for unbound workqueues, so guard
the call before per-cpu workqueues start using this path.

No functional change: only unbound workqueues reach apply_wqattrs_*()
today.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 38 insertions, 0 deletions

diff --git a/Documentation/admin-guide/braille-console.rst b/Documentation/admin-guide/braille-console.rst
new file mode 100644
index 000000000..153472e93
--- /dev/null
+++ b/Documentation/admin-guide/braille-console.rst
@@ -0,0 +1,38 @@
+Linux Braille Console
+=====================
+
+To get early boot messages on a braille device (before userspace screen
+readers can start), you first need to compile the support for the usual serial
+console (see :ref:`Documentation/admin-guide/serial-console.rst <serial_console>`), and
+for braille device
+(in :menuselection:`Device Drivers --> Accessibility support --> Console on braille device`).
+
+Then you need to specify a ``console=brl``, option on the kernel command line, the
+format is::
+
+	console=brl,serial_options...
+
+where ``serial_options...`` are the same as described in
+:ref:`Documentation/admin-guide/serial-console.rst <serial_console>`.
+
+So for instance you can use ``console=brl,ttyS0`` if the braille device is connected to the first serial port, and ``console=brl,ttyS0,115200`` to
+override the baud rate to 115200, etc.
+
+By default, the braille device will just show the last kernel message (console
+mode).  To review previous messages, press the Insert key to switch to the VT
+review mode.  In review mode, the arrow keys permit to browse in the VT content,
+`PAGE-UP`/`PAGE-DOWN` keys go at the top/bottom of the screen, and
+the `HOME` key goes back
+to the cursor, hence providing very basic screen reviewing facility.
+
+Sound feedback can be obtained by adding the ``braille_console.sound=1`` kernel
+parameter.
+
+For simplicity, only one braille console can be enabled, other uses of
+``console=brl,...`` will be discarded.  Also note that it does not interfere with
+the console selection mechanism described in
+:ref:`Documentation/admin-guide/serial-console.rst <serial_console>`.
+
+For now, only the VisioBraille device is supported.
+
+Samuel Thibault <samuel.thibault@ens-lyon.org>