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/mmc/mmc_sysfs.c b/drivers/mmc/mmc_sysfs.c
index d32698b..e0e82d8 100644
--- a/drivers/mmc/mmc_sysfs.c
+++ b/drivers/mmc/mmc_sysfs.c
@@ -86,31 +86,26 @@
 {
 	struct mmc_card *card = dev_to_mmc_card(dev);
 	char ccc[13];
-	int i = 0;
+	int retval = 0, i = 0, length = 0;
 
-#define add_env(fmt,val)						\
-	({								\
-		int len, ret = -ENOMEM;					\
-		if (i < num_envp) {					\
-			envp[i++] = buf;				\
-			len = snprintf(buf, buf_size, fmt, val) + 1;	\
-			buf_size -= len;				\
-			buf += len;					\
-			if (buf_size >= 0)				\
-				ret = 0;				\
-		}							\
-		ret;							\
-	})
+#define add_env(fmt,val) do {					\
+	retval = add_uevent_var(envp, num_envp, &i,		\
+				buf, buf_size, &length,		\
+				fmt, val);			\
+	if (retval)						\
+		return retval;					\
+} while (0);
 
 	for (i = 0; i < 12; i++)
 		ccc[i] = card->csd.cmdclass & (1 << i) ? '1' : '0';
 	ccc[12] = '\0';
 
-	i = 0;
 	add_env("MMC_CCC=%s", ccc);
 	add_env("MMC_MANFID=%06x", card->cid.manfid);
 	add_env("MMC_NAME=%s", mmc_card_name(card));
 	add_env("MMC_OEMID=%04x", card->cid.oemid);
+#undef add_env
+	envp[i] = NULL;
 
 	return 0;
 }