[PATCH] char/misc.c: misc_register: Do not loop on misc_list unconditionally

[Dae S. Kim]

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 <d...@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

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