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authorThadeu Lima de Souza Cascardo <cascardo@holoscopio.com>2009-12-14 18:00:31 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-15 08:53:27 -0800
commit1f2f38d89d1eced2079189cd880eeacee378370a (patch)
tree143d4219d4249591ef1e74688673f9b78ce06aa7 /drivers/char/misc.c
parent4ae717da8d18839487485f6ae608b8542790fdd3 (diff)
drivers/char/misc.c: use bitmap/bitops functions for dynamic minor number allocation
Use DECLARE_BITMAP(), find_first_zero_bit(), set_bit() and clear_bit() instead of rewriting code to do it with the minor number dynamic allocation bitmap. We need to invert the bit position to keep the code behaviour of using the last minor numbers first, since we don't have a find_last_zero_bit. Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/char/misc.c')
-rw-r--r--drivers/char/misc.c22
1 files changed, 9 insertions, 13 deletions
diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index a3a02f6303c..94a136e96c0 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -60,7 +60,7 @@ static DEFINE_MUTEX(misc_mtx);
* Assigned numbers, used for dynamic minors
*/
#define DYNAMIC_MINORS 64 /* like dynamic majors */
-static unsigned char misc_minors[DYNAMIC_MINORS / 8];
+static DECLARE_BITMAP(misc_minors, DYNAMIC_MINORS);
#ifdef CONFIG_PROC_FS
static void *misc_seq_start(struct seq_file *seq, loff_t *pos)
@@ -196,27 +196,23 @@ int misc_register(struct miscdevice * misc)
}
if (misc->minor == MISC_DYNAMIC_MINOR) {
- int i = DYNAMIC_MINORS;
- while (--i >= 0)
- if ( (misc_minors[i>>3] & (1 << (i&7))) == 0)
- break;
- if (i<0) {
+ int i = find_first_zero_bit(misc_minors, DYNAMIC_MINORS);
+ if (i >= DYNAMIC_MINORS) {
mutex_unlock(&misc_mtx);
return -EBUSY;
}
- misc->minor = i;
+ misc->minor = DYNAMIC_MINORS - i - 1;
+ set_bit(i, misc_minors);
}
- if (misc->minor < DYNAMIC_MINORS)
- misc_minors[misc->minor >> 3] |= 1 << (misc->minor & 7);
dev = MKDEV(MISC_MAJOR, misc->minor);
misc->this_device = device_create(misc_class, misc->parent, dev,
misc, "%s", misc->name);
if (IS_ERR(misc->this_device)) {
- int i = misc->minor;
+ int i = DYNAMIC_MINORS - misc->minor - 1;
if (i < DYNAMIC_MINORS && i >= 0)
- misc_minors[i>>3] &= ~(1 << (i & 7));
+ clear_bit(i, misc_minors);
err = PTR_ERR(misc->this_device);
goto out;
}
@@ -243,7 +239,7 @@ int misc_register(struct miscdevice * misc)
int misc_deregister(struct miscdevice *misc)
{
- int i = misc->minor;
+ int i = DYNAMIC_MINORS - misc->minor - 1;
if (list_empty(&misc->list))
return -EINVAL;
@@ -252,7 +248,7 @@ int misc_deregister(struct miscdevice *misc)
list_del(&misc->list);
device_destroy(misc_class, MKDEV(MISC_MAJOR, misc->minor));
if (i < DYNAMIC_MINORS && i >= 0)
- misc_minors[i>>3] &= ~(1 << (i & 7));
+ clear_bit(i, misc_minors);
mutex_unlock(&misc_mtx);
return 0;
}