Messages in this thread Patch in this message | | | Date | Mon, 17 Dec 2012 23:26:38 +0100 | From | "Dae S. Kim" <> | Subject | [PATCH] char/misc.c: misc_register: Do not loop on misc_list unconditionally |
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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
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