linux-kernel - [PATCH] staging: rtl8188eu: Simplify memcmp logical checks

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Message-Id: <20180921002221.14424-1-natechancellor@gmail.com>
Date:   Thu, 20 Sep 2018 17:22:21 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
        Nathan Chancellor <natechancellor@...il.com>
Subject: [PATCH] staging: rtl8188eu: Simplify memcmp logical checks

Clang generates a warning when it sees a logical not followed by a
conditional operator like ==, >, or < because it thinks that the logical
not should be applied to the whole statement:

drivers/staging/rtl8188eu/core/rtw_ieee80211.c:293:8: warning: logical
not is only applied to the left hand side of this comparison
[-Wlogical-not-parentheses]

It assumes the author might have made a mistake in their logic:

if (!a == b) -> if (!(a == b))

Sometimes that is the case; other times, it's just a super convoluted
way of saying 'if (a)' when b = 0:

if (!1 == 0) -> if (0 == 0) -> if (true)

Alternatively:

if (!1 == 0) -> if (!!1) -> if (1)

Simplify these comparisons so that Clang doesn't complain.

Link: https://github.com/ClangBuiltLinux/linux/issues/161
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---
 drivers/staging/rtl8188eu/core/rtw_ieee80211.c | 2 +-
 drivers/staging/rtl8188eu/core/rtw_mlme.c      | 2 +-
 drivers/staging/rtl8188eu/core/rtw_recv.c      | 4 ++--
 drivers/staging/rtl8188eu/core/rtw_wlan_util.c | 2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/rtl8188eu/core/rtw_ieee80211.c b/drivers/staging/rtl8188eu/core/rtw_ieee80211.c
index 9e5c7e62d26f..20f34d25c369 100644
--- a/drivers/staging/rtl8188eu/core/rtw_ieee80211.c
+++ b/drivers/staging/rtl8188eu/core/rtw_ieee80211.c
@@ -284,7 +284,7 @@ unsigned char *rtw_get_wpa_ie(unsigned char *pie, uint *wpa_ie_len, int limit)
 
 		if (pbuf) {
 			/* check if oui matches... */
-			if (!memcmp((pbuf + 2), wpa_oui_type, sizeof(wpa_oui_type)) == false)
+			if (memcmp((pbuf + 2), wpa_oui_type, sizeof(wpa_oui_type)))
 				goto check_next_ie;
 
 			/* check version... */
diff --git a/drivers/staging/rtl8188eu/core/rtw_mlme.c b/drivers/staging/rtl8188eu/core/rtw_mlme.c
index ef8a7dc4bd34..43d6513484c5 100644
--- a/drivers/staging/rtl8188eu/core/rtw_mlme.c
+++ b/drivers/staging/rtl8188eu/core/rtw_mlme.c
@@ -1437,7 +1437,7 @@ static int rtw_check_join_candidate(struct mlme_priv *pmlmepriv
 	/* check ssid, if needed */
 	if (pmlmepriv->assoc_ssid.SsidLength) {
 		if (competitor->network.Ssid.SsidLength != pmlmepriv->assoc_ssid.SsidLength ||
-		    !memcmp(competitor->network.Ssid.Ssid, pmlmepriv->assoc_ssid.Ssid, pmlmepriv->assoc_ssid.SsidLength) == false)
+		    memcmp(competitor->network.Ssid.Ssid, pmlmepriv->assoc_ssid.Ssid, pmlmepriv->assoc_ssid.SsidLength))
 			goto exit;
 	}
 
diff --git a/drivers/staging/rtl8188eu/core/rtw_recv.c b/drivers/staging/rtl8188eu/core/rtw_recv.c
index ab9638d618a9..f3eb63f8cf0b 100644
--- a/drivers/staging/rtl8188eu/core/rtw_recv.c
+++ b/drivers/staging/rtl8188eu/core/rtw_recv.c
@@ -1283,8 +1283,8 @@ static int wlanhdr_to_ethhdr(struct recv_frame *precvframe)
 	psnap_type = ptr+pattrib->hdrlen + pattrib->iv_len+SNAP_SIZE;
 	/* convert hdr + possible LLC headers into Ethernet header */
 	if ((!memcmp(psnap, rtw_rfc1042_header, SNAP_SIZE) &&
-	     (!memcmp(psnap_type, SNAP_ETH_TYPE_IPX, 2) == false) &&
-	     (!memcmp(psnap_type, SNAP_ETH_TYPE_APPLETALK_AARP, 2) == false)) ||
+	     memcmp(psnap_type, SNAP_ETH_TYPE_IPX, 2) &&
+	     memcmp(psnap_type, SNAP_ETH_TYPE_APPLETALK_AARP, 2)) ||
 	     !memcmp(psnap, rtw_bridge_tunnel_header, SNAP_SIZE)) {
 		/* remove RFC1042 or Bridge-Tunnel encapsulation and replace EtherType */
 		bsnaphdr = true;
diff --git a/drivers/staging/rtl8188eu/core/rtw_wlan_util.c b/drivers/staging/rtl8188eu/core/rtw_wlan_util.c
index fb496ab5a862..51cf78150168 100644
--- a/drivers/staging/rtl8188eu/core/rtw_wlan_util.c
+++ b/drivers/staging/rtl8188eu/core/rtw_wlan_util.c
@@ -856,7 +856,7 @@ int rtw_check_bcn_info(struct adapter  *Adapter, u8 *pframe, u32 packet_len)
 		return _FAIL;
 	}
 
-	if (!memcmp(cur_network->network.MacAddress, pbssid, 6) == false) {
+	if (memcmp(cur_network->network.MacAddress, pbssid, 6) {
 		DBG_88E("Oops: rtw_check_network_encrypt linked but recv other bssid bcn\n%pM %pM\n",
 			(pbssid), (cur_network->network.MacAddress));
 		return true;
-- 
2.19.0