diff options
Diffstat (limited to 'drivers/char/misc.c')
| -rw-r--r-- | drivers/char/misc.c | 39 |
1 files changed, 30 insertions, 9 deletions
diff --git a/drivers/char/misc.c b/drivers/char/misc.c index 541edc26ec89..2cf595d2e10b 100644 --- a/drivers/char/misc.c +++ b/drivers/char/misc.c @@ -63,16 +63,30 @@ static DEFINE_MUTEX(misc_mtx); #define DYNAMIC_MINORS 128 /* like dynamic majors */ static DEFINE_IDA(misc_minors_ida); -static int misc_minor_alloc(void) +static int misc_minor_alloc(int minor) { - int ret; - - ret = ida_alloc_max(&misc_minors_ida, DYNAMIC_MINORS - 1, GFP_KERNEL); - if (ret >= 0) { - ret = DYNAMIC_MINORS - ret - 1; + int ret = 0; + + if (minor == MISC_DYNAMIC_MINOR) { + /* allocate free id */ + ret = ida_alloc_max(&misc_minors_ida, DYNAMIC_MINORS - 1, GFP_KERNEL); + if (ret >= 0) { + ret = DYNAMIC_MINORS - ret - 1; + } else { + ret = ida_alloc_range(&misc_minors_ida, MISC_DYNAMIC_MINOR + 1, + MINORMASK, GFP_KERNEL); + } } else { - ret = ida_alloc_range(&misc_minors_ida, MISC_DYNAMIC_MINOR + 1, - MINORMASK, GFP_KERNEL); + /* specific minor, check if it is in dynamic or misc dynamic range */ + if (minor < DYNAMIC_MINORS) { + minor = DYNAMIC_MINORS - minor - 1; + ret = ida_alloc_range(&misc_minors_ida, minor, minor, GFP_KERNEL); + } else if (minor > MISC_DYNAMIC_MINOR) { + ret = ida_alloc_range(&misc_minors_ida, minor, minor, GFP_KERNEL); + } else { + /* case of non-dynamic minors, no need to allocate id */ + ret = 0; + } } return ret; } @@ -219,7 +233,7 @@ int misc_register(struct miscdevice *misc) mutex_lock(&misc_mtx); if (is_dynamic) { - int i = misc_minor_alloc(); + int i = misc_minor_alloc(misc->minor); if (i < 0) { err = -EBUSY; @@ -228,6 +242,7 @@ int misc_register(struct miscdevice *misc) misc->minor = i; } else { struct miscdevice *c; + int i; list_for_each_entry(c, &misc_list, list) { if (c->minor == misc->minor) { @@ -235,6 +250,12 @@ int misc_register(struct miscdevice *misc) goto out; } } + + i = misc_minor_alloc(misc->minor); + if (i < 0) { + err = -EBUSY; + goto out; + } } dev = MKDEV(MISC_MAJOR, misc->minor); |