dmi: don't save the same device twice

Now that we gather on-board devices from both DMI types 10 and 41, there is
a possibility that we list the same device twice.  In order to not confuse
drivers, and also to save memory, make sure that we do not add duplicate
devices to the dmi_devices list.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 653265a..de30275 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -10,10 +10,9 @@
 
 static char dmi_empty_string[] = "        ";
 
-static char * __init dmi_string(const struct dmi_header *dm, u8 s)
+static const char * __init dmi_string_nosave(const struct dmi_header *dm, u8 s)
 {
 	const u8 *bp = ((u8 *) dm) + dm->length;
-	char *str = "";
 
 	if (s) {
 		s--;
@@ -28,14 +27,29 @@
 
 			if (!memcmp(bp, dmi_empty_string, cmp_len))
 				return dmi_empty_string;
-			str = dmi_alloc(len);
-			if (str != NULL)
-				strcpy(str, bp);
-			else
-				printk(KERN_ERR "dmi_string: cannot allocate %Zu bytes.\n", len);
+			return bp;
 		}
 	}
 
+	return "";
+}
+
+static char * __init dmi_string(const struct dmi_header *dm, u8 s)
+{
+	const char *bp = dmi_string_nosave(dm, s);
+	char *str;
+	size_t len;
+
+	if (bp == dmi_empty_string)
+		return dmi_empty_string;
+
+	len = strlen(bp) + 1;
+	str = dmi_alloc(len);
+	if (str != NULL)
+		strcpy(str, bp);
+	else
+		printk(KERN_ERR "dmi_string: cannot allocate %Zu bytes.\n", len);
+
 	return str;
 }
 
@@ -167,10 +181,30 @@
 	dmi_ident[slot] = s;
 }
 
+static void __init dmi_save_one_device(int type, const char *name)
+{
+	struct dmi_device *dev;
+
+	/* No duplicate device */
+	if (dmi_find_device(type, name, NULL))
+		return;
+
+	dev = dmi_alloc(sizeof(*dev) + strlen(name) + 1);
+	if (!dev) {
+		printk(KERN_ERR "dmi_save_one_device: out of memory.\n");
+		return;
+	}
+
+	dev->type = type;
+	strcpy((char *)(dev + 1), name);
+	dev->name = (char *)(dev + 1);
+	dev->device_data = NULL;
+	list_add(&dev->list, &dmi_devices);
+}
+
 static void __init dmi_save_devices(const struct dmi_header *dm)
 {
 	int i, count = (dm->length - sizeof(struct dmi_header)) / 2;
-	struct dmi_device *dev;
 
 	for (i = 0; i < count; i++) {
 		const char *d = (char *)(dm + 1) + (i * 2);
@@ -179,16 +213,7 @@
 		if ((*d & 0x80) == 0)
 			continue;
 
-		dev = dmi_alloc(sizeof(*dev));
-		if (!dev) {
-			printk(KERN_ERR "dmi_save_devices: out of memory.\n");
-			break;
-		}
-
-		dev->type = *d++ & 0x7f;
-		dev->name = dmi_string(dm, *d);
-		dev->device_data = NULL;
-		list_add(&dev->list, &dmi_devices);
+		dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d + 1)));
 	}
 }
 
@@ -253,23 +278,12 @@
 static void __init dmi_save_extended_devices(const struct dmi_header *dm)
 {
 	const u8 *d = (u8*) dm + 5;
-	struct dmi_device *dev;
 
 	/* Skip disabled device */
 	if ((*d & 0x80) == 0)
 		return;
 
-	dev = dmi_alloc(sizeof(*dev));
-	if (!dev) {
-		printk(KERN_ERR "dmi_save_extended_devices: out of memory.\n");
-		return;
-	}
-
-	dev->type = *d-- & 0x7f;
-	dev->name = dmi_string(dm, *d);
-	dev->device_data = NULL;
-
-	list_add(&dev->list, &dmi_devices);
+	dmi_save_one_device(*d & 0x7f, dmi_string_nosave(dm, *(d - 1)));
 }
 
 /*