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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>
This commit is contained in:
Dae S. Kim 2013-02-27 17:05:14 -08:00 committed by Linus Torvalds
parent f2afae4629
commit 3c94ce6f48
1 changed files with 9 additions and 7 deletions
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16
drivers/char/misc.c
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@ -183,19 +183,12 @@ static const struct file_operations misc_fops = {
int misc_register(struct miscdevice * misc) int misc_register(struct miscdevice * misc)
{ {
struct miscdevice *c;
dev_t dev; dev_t dev;
int err = 0; int err = 0;
INIT_LIST_HEAD(&misc->list); INIT_LIST_HEAD(&misc->list);
mutex_lock(&misc_mtx); 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) { if (misc->minor == MISC_DYNAMIC_MINOR) {
int i = find_first_zero_bit(misc_minors, DYNAMIC_MINORS); 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; misc->minor = DYNAMIC_MINORS - i - 1;
set_bit(i, misc_minors); 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); dev = MKDEV(MISC_MAJOR, misc->minor);