[PATCH v2] wireless: mark expected switch fall-throughs

[Gustavo A. R. Silva]

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Warning level 3 was used: -Wimplicit-fallthrough=3

This code was not tested and GCC 7.2.0 was used to compile it.

Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
---
Changes in v2:
 - Explicity mention in the commit log that this the code was not
   tested.
 - Use warning level 3 instead of 2.
 - Change the form "else: fall through" to "fall through" instead.
 - Address -Wimplicit-fallthrough warnings in net/wireless/scan.c

 net/wireless/chan.c        | 2 ++
 net/wireless/nl80211.c     | 9 +++++++++
 net/wireless/scan.c        | 2 +-
 net/wireless/wext-compat.c | 2 ++
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index 2db713d..0a45265 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -747,6 +747,7 @@ bool cfg80211_chandef_usable(struct wiphy *wiphy,
 	case NL80211_CHAN_WIDTH_20:
 		if (!ht_cap->ht_supported)
 			return false;
+		/* fall through */
 	case NL80211_CHAN_WIDTH_20_NOHT:
 		prohibited_flags |= IEEE80211_CHAN_NO_20MHZ;
 		width = 20;
@@ -769,6 +770,7 @@ bool cfg80211_chandef_usable(struct wiphy *wiphy,
 		cap = vht_cap->cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK;
 		if (cap != IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ)
 			return false;
+		/* fall through */
 	case NL80211_CHAN_WIDTH_80:
 		if (!vht_cap->vht_supported)
 			return false;
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 744b585..0276370 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -1706,6 +1706,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 		state->split_start++;
 		if (state->split)
 			break;
+		/* fall through */
 	case 1:
 		if (nla_put(msg, NL80211_ATTR_CIPHER_SUITES,
 			    sizeof(u32) * rdev->wiphy.n_cipher_suites,
@@ -1752,6 +1753,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 		state->split_start++;
 		if (state->split)
 			break;
+		/* fall through */
 	case 2:
 		if (nl80211_put_iftypes(msg, NL80211_ATTR_SUPPORTED_IFTYPES,
 					rdev->wiphy.interface_modes))
@@ -1759,6 +1761,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 		state->split_start++;
 		if (state->split)
 			break;
+		/* fall through */
 	case 3:
 		nl_bands = nla_nest_start(msg, NL80211_ATTR_WIPHY_BANDS);
 		if (!nl_bands)
@@ -1784,6 +1787,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 				state->chan_start++;
 				if (state->split)
 					break;
+				/* fall through */
 			default:
 				/* add frequencies */
 				nl_freqs = nla_nest_start(
@@ -1837,6 +1841,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 			state->split_start++;
 		if (state->split)
 			break;
+		/* fall through */
 	case 4:
 		nl_cmds = nla_nest_start(msg, NL80211_ATTR_SUPPORTED_COMMANDS);
 		if (!nl_cmds)
@@ -1863,6 +1868,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 		state->split_start++;
 		if (state->split)
 			break;
+		/* fall through */
 	case 5:
 		if (rdev->ops->remain_on_channel &&
 		    (rdev->wiphy.flags & WIPHY_FLAG_HAS_REMAIN_ON_CHANNEL) &&
@@ -1880,6 +1886,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 		state->split_start++;
 		if (state->split)
 			break;
+		/* fall through */
 	case 6:
 #ifdef CONFIG_PM
 		if (nl80211_send_wowlan(msg, rdev, state->split))
@@ -1890,6 +1897,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 #else
 		state->split_start++;
 #endif
+		/* fall through */
 	case 7:
 		if (nl80211_put_iftypes(msg, NL80211_ATTR_SOFTWARE_IFTYPES,
 					rdev->wiphy.software_iftypes))
@@ -1902,6 +1910,7 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 		state->split_start++;
 		if (state->split)
 			break;
+		/* fall through */
 	case 8:
 		if ((rdev->wiphy.flags & WIPHY_FLAG_HAVE_AP_SME) &&
 		    nla_put_u32(msg, NL80211_ATTR_DEVICE_AP_SME,
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index d0e7472..0f0b519 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -1183,7 +1183,7 @@ cfg80211_inform_bss_data(struct wiphy *wiphy,
 	switch (ftype) {
 	case CFG80211_BSS_FTYPE_BEACON:
 		ies->from_beacon = true;
-		/* fall through to assign */
+		/* fall through - to assign */
 	case CFG80211_BSS_FTYPE_UNKNOWN:
 		rcu_assign_pointer(tmp.pub.beacon_ies, ies);
 		break;
diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
index 06943d9..d522787 100644
--- a/net/wireless/wext-compat.c
+++ b/net/wireless/wext-compat.c
@@ -1337,6 +1337,7 @@ static struct iw_statistics *cfg80211_wireless_stats(struct net_device *dev)
 			wstats.qual.qual = sig + 110;
 			break;
 		}
+		/* fall through */
 	case CFG80211_SIGNAL_TYPE_UNSPEC:
 		if (sinfo.filled & BIT_ULL(NL80211_STA_INFO_SIGNAL)) {
 			wstats.qual.updated |= IW_QUAL_LEVEL_UPDATED;
@@ -1345,6 +1346,7 @@ static struct iw_statistics *cfg80211_wireless_stats(struct net_device *dev)
 			wstats.qual.qual = sinfo.signal;
 			break;
 		}
+		/* fall through */
 	default:
 		wstats.qual.updated |= IW_QUAL_LEVEL_INVALID;
 		wstats.qual.updated |= IW_QUAL_QUAL_INVALID;
-- 
2.7.4