Re: [PATCH v2] net: dsa: Remove VLA usage

We avoid 2 VLAs by using a pre-allocated field in dsa_switch. We also
try to avoid dynamic allocation whenever possible (when using fewer than
bits-per-long ports, which is the common case).

Link: http://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Link: http://lkml.kernel.org/r/20180505185145.GB32630@lunn.ch
Signed-off-by: Salvatore Mesoraca <redacted>
[kees: tweak commit subject and message slightly]
Signed-off-by: Kees Cook <redacted>
---
 include/net/dsa.h |  3 +++
 net/dsa/dsa2.c    | 14 ++++++++++++++
 net/dsa/switch.c  | 22 ++++++++++------------
 3 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/include/net/dsa.h b/include/net/dsa.h
index fdbd6082945d..461e8a7661b7 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h

@@ -259,6 +259,9 @@ struct dsa_switch {
 	/* Number of switch port queues */
 	unsigned int		num_tx_queues;
 
+	unsigned long		*bitmap;
+	unsigned long		_bitmap;