From: Dae S. Kim <dae@velatum.com>
Date: Wed, 20 Feb 2013 02:16:33 +0000 (+1100)
Subject: drivers/char/misc.c:misc_register(): do not loop on misc_list unconditionally
X-Git-Tag: next-20130220~1^2~104
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=0447b14453fafb1dddc890f8d1f01a1a020c7e86;p=karo-tx-linux.git

drivers/char/misc.c:misc_register(): do not loop on misc_list unconditionally

If the minor number is assigned dynamically, there is no need to search
for misc->minor in misc_list, since misc->minor == MISC_DYNAMIC_MINOR.

Signed-off-by: Dae S. Kim <dae@velatum.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index 522136d40843..7b262b69c653 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -190,12 +190,6 @@ int misc_register(struct miscdevice * misc)
 	INIT_LIST_HEAD(&misc->list);
 
 	mutex_lock(&misc_mtx);
-	list_for_each_entry(c, &misc_list, list) {
-		if (c->minor == misc->minor) {
-			mutex_unlock(&misc_mtx);
-			return -EBUSY;
-		}
-	}
 
 	if (misc->minor == MISC_DYNAMIC_MINOR) {
 		int i = find_first_zero_bit(misc_minors, DYNAMIC_MINORS);
@@ -205,6 +199,13 @@ int misc_register(struct miscdevice * misc)
 		}
 		misc->minor = DYNAMIC_MINORS - i - 1;
 		set_bit(i, misc_minors);
+	} else {
+		list_for_each_entry(c, &misc_list, list) {
+			if (c->minor == misc->minor) {
+				mutex_unlock(&misc_mtx);
+				return -EBUSY;
+			}
+		}
 	}
 
 	dev = MKDEV(MISC_MAJOR, misc->minor);