From 3c94ce6f48f484bbc4dba83c0ed1f98f5e10957c Mon Sep 17 00:00:00 2001 From: "Dae S. Kim" 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 Cc: Arnd Bergmann Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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 522136d..190d442 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); -- 2.7.4