mac80211: make alignment warning optional

Driver authors should be aware of the alignment requirements, but
not everybody cares about the warning. This patch makes it depend
on a new Kconfig symbol MAC80211_DEBUG_PACKET_ALIGNMENT which can
be enabled regardless of MAC80211_DEBUG and is recommended for
driver authors (only). This also restricts the warning to data
packets so other packets need not be realigned to not trigger the
warning.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/net/mac80211/Kconfig b/net/mac80211/Kconfig
index 09c255002e5..e77592d050c 100644
--- a/net/mac80211/Kconfig
+++ b/net/mac80211/Kconfig
@@ -98,6 +98,18 @@ config MAC80211_DEBUGFS
 
           Say N unless you know you need this.
 
+config MAC80211_DEBUG_PACKET_ALIGNMENT
+        bool "Enable packet alignment debugging"
+        depends on MAC80211
+        help
+          This option is recommended for driver authors and strongly
+          discouraged for everybody else, it will trigger a warning
+          when a driver hands mac80211 a buffer that is aligned in
+          a way that will cause problems with the IP stack on some
+          architectures.
+
+          Say N unless you're writing a mac80211 based driver.
+
 config MAC80211_DEBUG
         bool "Enable debugging output"
         depends on MAC80211