uevent: use add_uevent_var() instead of open coding it

Make use of add_uevent_var() instead of (often incorrectly) open coding it.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Eric Rannaud <eric.rannaud@gmail.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/ieee1394/nodemgr.c b/drivers/ieee1394/nodemgr.c
index c5ace19..1644e6fd 100644
--- a/drivers/ieee1394/nodemgr.c
+++ b/drivers/ieee1394/nodemgr.c
@@ -1163,6 +1163,7 @@
 	struct unit_directory *ud;
 	int i = 0;
 	int length = 0;
+	int retval = 0;
 	/* ieee1394:venNmoNspNverN */
 	char buf[8 + 1 + 3 + 8 + 2 + 8 + 2 + 8 + 3 + 8 + 1];
 
@@ -1176,14 +1177,11 @@
 
 #define PUT_ENVP(fmt,val) 					\
 do {								\
-    	int printed;						\
-	envp[i++] = buffer;					\
-	printed = snprintf(buffer, buffer_size - length,	\
-			   fmt, val);				\
-	if ((buffer_size - (length+printed) <= 0) || (i >= num_envp))	\
-		return -ENOMEM;					\
-	length += printed+1;					\
-	buffer += printed+1;					\
+	retval = add_uevent_var(envp, num_envp, &i,		\
+				buffer, buffer_size, &length,	\
+				fmt, val);			\
+	if (retval)						\
+		return retval;					\
 } while (0)
 
 	PUT_ENVP("VENDOR_ID=%06x", ud->vendor_id);