From 3c94ce6f48f484bbc4dba83c0ed1f98f5e10957c Mon Sep 17 00:00:00 2001
From: "Dae S. Kim" <dae@velatum.com>
Date: Wed, 27 Feb 2013 17:05:14 -0800
Subject: [PATCH] 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.
[akpm@linux-foundation.org: reduce scope of local `c']
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
drivers/char/misc.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index 522136d40843e..190d4423653f6 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -183,19 +183,12 @@ static const struct file_operations misc_fops = {
int misc_register(struct miscdevice * misc)
{
- struct miscdevice *c;
dev_t dev;
int err = 0;
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 +198,15 @@ int misc_register(struct miscdevice * misc)
}
misc->minor = DYNAMIC_MINORS - i - 1;
set_bit(i, misc_minors);
+ } else {
+ struct miscdevice *c;
+
+ 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);