From: "Dae S. Kim" <dae@velatum.com>
To: arnd@arndb.de
Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org
Subject: [PATCH] char/misc.c: misc_register: Do not loop on misc_list unconditionally
Date: Mon, 17 Dec 2012 23:26:38 +0100 [thread overview]
Message-ID: <20121217222638.GA3747@Delta> (raw)
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>
---
drivers/char/misc.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index 522136d..7b262b6 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);
--
1.7.9.5
next reply other threads:[~2012-12-17 22:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-17 22:26 Dae S. Kim [this message]
2012-12-19 23:12 ` [PATCH] char/misc.c: misc_register: Do not loop on misc_list unconditionally Andrew Morton
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