isdn: isdnloop: fix logic error in isdnloop_sendbuf

arndb · davem330 · commit eef5a7cc2a57 · 2017-09-07T20:03:54.000-07:00
gcc-7 found an ancient bug in the loop driver, leading to a condition that is always false, meaning we ignore the contents of 'card->flags' here: drivers/isdn/isdnloop/isdnloop.c:412:37: error: ?: using integer constants in boolean context, the expression will always evaluate to 'true' [-Werror=int-in-bool-context] This changes the braces in the expression to ensure we actually compare the flag bits, rather than comparing a constant. As Joe Perches pointed out, an earlier patch of mine incorrectly assumed this was a false-positive warning. Cc: Joe Perches <joe@perches.com> Link: https://patchwork.kernel.org/patch/9840289/ Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/isdn/isdnloop/isdnloop.c b/drivers/isdn/isdnloop/isdnloop.c
@@ -409,7 +409,7 @@ isdnloop_sendbuf(int channel, struct sk_buff *skb, isdnloop_card *card)
 		return -EINVAL;
 	}
 	if (len) {
-		if (!(card->flags & (channel) ? ISDNLOOP_FLAGS_B2ACTIVE : ISDNLOOP_FLAGS_B1ACTIVE))
+		if (!(card->flags & (channel ? ISDNLOOP_FLAGS_B2ACTIVE : ISDNLOOP_FLAGS_B1ACTIVE)))
 			return 0;
 		if (card->sndcount[channel] > ISDNLOOP_MAX_SQUEUE)
 			return 0;

Original file line number	Diff line number	Diff line change
`@@ -409,7 +409,7 @@ isdnloop_sendbuf(int channel, struct sk_buff skb, isdnloop_card card)`
`409`	`409`	`return -EINVAL;`
`410`	`410`	`}`
`411`	`411`	`if (len) {`
`412`		`- if (!(card->flags & (channel) ? ISDNLOOP_FLAGS_B2ACTIVE : ISDNLOOP_FLAGS_B1ACTIVE))`
	`412`	`+ if (!(card->flags & (channel ? ISDNLOOP_FLAGS_B2ACTIVE : ISDNLOOP_FLAGS_B1ACTIVE)))`
`413`	`413`	`return 0;`
`414`	`414`	`if (card->sndcount[channel] > ISDNLOOP_MAX_SQUEUE)`
`415`	`415`	`return 0;`