[PATCH v2] staging: dgnc: replace DGNC_VERIFY_BOARD macro with dgnc_verify_board function.

[Elise Lennion <elise.lennion@gmail.com>]

Fix checkpatch warning:

WARNING: Macros with flow control statements should be avoided

Macros with flow control statements should be avoided. They break
the flow of the calling function and make it harder to test the code.

Signed-off-by: Elise Lennion <elise.lennion@gmail.com>
---

v2: Fixed the return values of dgnc_verify_board. 
    Reworked to return NULL instead of 0, as suggested 
    by Julia Lawall <julia.lawall@lip6.fr>.

 drivers/staging/dgnc/dgnc_sysfs.c | 74 +++++++++++++++++++++++++++------------
 1 file changed, 51 insertions(+), 23 deletions(-)

diff --git a/drivers/staging/dgnc/dgnc_sysfs.c b/drivers/staging/dgnc/dgnc_sysfs.c
index 290bf6e..cdec40a 100644
--- a/drivers/staging/dgnc/dgnc_sysfs.c
+++ b/drivers/staging/dgnc/dgnc_sysfs.c
@@ -90,17 +90,21 @@ void dgnc_remove_driver_sysfiles(struct pci_driver *dgnc_driver)
 	driver_remove_file(driverfs, &driver_attr_pollrate);
 }
 
-#define DGNC_VERIFY_BOARD(p, bd)				\
-	do {							\
-		if (!p)						\
-			return 0;				\
-								\
-		bd = dev_get_drvdata(p);			\
-		if (!bd || bd->magic != DGNC_BOARD_MAGIC)	\
-			return 0;				\
-		if (bd->state != BOARD_READY)			\
-			return 0;				\
-	} while (0)
+static struct dgnc_board *dgnc_verify_board(struct device *p)
+{
+	struct dgnc_board *bd;
+
+	if (!p)
+		return NULL;
+
+	bd = dev_get_drvdata(p);
+	if (!bd || bd->magic != DGNC_BOARD_MAGIC)
+		return NULL;
+	if (bd->state != BOARD_READY)
+		return NULL;
+
+	return bd;
+}
 
 static ssize_t vpd_show(struct device *p, struct device_attribute *attr,
 			char *buf)
@@ -109,7 +113,9 @@ static ssize_t vpd_show(struct device *p, struct device_attribute *attr,
 	int count = 0;
 	int i = 0;
 
-	DGNC_VERIFY_BOARD(p, bd);
+	bd = dgnc_verify_board(p);
+	if (!bd)
+		return 0;
 
 	count += sprintf(buf + count,
 		"\n      0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F");
@@ -130,7 +136,9 @@ static ssize_t serial_number_show(struct device *p,
 	struct dgnc_board *bd;
 	int count = 0;
 
-	DGNC_VERIFY_BOARD(p, bd);
+	bd = dgnc_verify_board(p);
+	if (!bd)
+		return 0;
 
 	if (bd->serial_num[0] == '\0')
 		count += sprintf(buf + count, "<UNKNOWN>\n");
@@ -148,7 +156,9 @@ static ssize_t ports_state_show(struct device *p,
 	int count = 0;
 	int i = 0;
 
-	DGNC_VERIFY_BOARD(p, bd);
+	bd = dgnc_verify_board(p);
+	if (!bd)
+		return 0;
 
 	for (i = 0; i < bd->nasync; i++) {
 		count += snprintf(buf + count, PAGE_SIZE - count,
@@ -166,7 +176,9 @@ static ssize_t ports_baud_show(struct device *p,
 	int count = 0;
 	int i = 0;
 
-	DGNC_VERIFY_BOARD(p, bd);
+	bd = dgnc_verify_board(p);
+	if (!bd)
+		return 0;
 
 	for (i = 0; i < bd->nasync; i++) {
 		count +=  snprintf(buf + count, PAGE_SIZE - count,
@@ -184,7 +196,9 @@ static ssize_t ports_msignals_show(struct device *p,
 	int count = 0;
 	int i = 0;
 
-	DGNC_VERIFY_BOARD(p, bd);
+	bd = dgnc_verify_board(p);
+	if (!bd)
+		return 0;
 
 	for (i = 0; i < bd->nasync; i++) {
 		struct channel_t *ch = bd->channels[i];
@@ -215,7 +229,9 @@ static ssize_t ports_iflag_show(struct device *p,
 	int count = 0;
 	int i = 0;
 
-	DGNC_VERIFY_BOARD(p, bd);
+	bd = dgnc_verify_board(p);
+	if (!bd)
+		return 0;
 
 	for (i = 0; i < bd->nasync; i++) {
 		count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -233,7 +249,9 @@ static ssize_t ports_cflag_show(struct device *p,
 	int count = 0;
 	int i = 0;
 
-	DGNC_VERIFY_BOARD(p, bd);
+	bd = dgnc_verify_board(p);
+	if (!bd)
+		return 0;
 
 	for (i = 0; i < bd->nasync; i++) {
 		count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -251,7 +269,9 @@ static ssize_t ports_oflag_show(struct device *p,
 	int count = 0;
 	int i = 0;
 
-	DGNC_VERIFY_BOARD(p, bd);
+	bd = dgnc_verify_board(p);
+	if (!bd)
+		return 0;
 
 	for (i = 0; i < bd->nasync; i++) {
 		count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -269,7 +289,9 @@ static ssize_t ports_lflag_show(struct device *p,
 	int count = 0;
 	int i = 0;
 
-	DGNC_VERIFY_BOARD(p, bd);
+	bd = dgnc_verify_board(p);
+	if (!bd)
+		return 0;
 
 	for (i = 0; i < bd->nasync; i++) {
 		count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -287,7 +309,9 @@ static ssize_t ports_digi_flag_show(struct device *p,
 	int count = 0;
 	int i = 0;
 
-	DGNC_VERIFY_BOARD(p, bd);
+	bd = dgnc_verify_board(p);
+	if (!bd)
+		return 0;
 
 	for (i = 0; i < bd->nasync; i++) {
 		count += snprintf(buf + count, PAGE_SIZE - count, "%d %x\n",
@@ -305,7 +329,9 @@ static ssize_t ports_rxcount_show(struct device *p,
 	int count = 0;
 	int i = 0;
 
-	DGNC_VERIFY_BOARD(p, bd);
+	bd = dgnc_verify_board(p);
+	if (!bd)
+		return 0;
 
 	for (i = 0; i < bd->nasync; i++) {
 		count += snprintf(buf + count, PAGE_SIZE - count, "%d %ld\n",
@@ -323,7 +349,9 @@ static ssize_t ports_txcount_show(struct device *p,
 	int count = 0;
 	int i = 0;
 
-	DGNC_VERIFY_BOARD(p, bd);
+	bd = dgnc_verify_board(p);
+	if (!bd)
+		return 0;
 
 	for (i = 0; i < bd->nasync; i++) {
 		count += snprintf(buf + count, PAGE_SIZE - count, "%d %ld\n",
-- 
2.7.4