The patch titled
drivers/char/misc.c: use bitmap/bitops functions for dynamic minor number allocation
has been added to the -mm tree. Its filename is
drivers-char-miscc-use-bitmap-bitops-functions-for-dynamic-minor-number-allocation.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: drivers/char/misc.c: use bitmap/bitops functions for dynamic minor number allocation
From: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/char/misc.c | 22 +++++++++-------------
1 file changed, 9 insertions(+), 13 deletions(-)
diff -puN drivers/char/misc.c~drivers-char-miscc-use-bitmap-bitops-functions-for-dynamic-minor-number-allocation drivers/char/misc.c
--- a/drivers/char/misc.c~drivers-char-miscc-use-bitmap-bitops-functions-for-dynamic-minor-number-allocation
+++ a/drivers/char/misc.c
@@ -61,7 +61,7 @@ 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)
@@ -199,27 +199,23 @@ int misc_register(struct miscdevice * mi
}
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;
}
@@ -246,7 +242,7 @@ int misc_register(struct miscdevice * mi
int misc_deregister(struct miscdevice *misc)
{
- int i = misc->minor;
+ int i = DYNAMIC_MINORS - misc->minor - 1;
if (list_empty(&misc->list))
return -EINVAL;
@@ -255,7 +251,7 @@ int misc_deregister(struct miscdevice *m
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;
}
_
Patches currently in -mm which might be from cascardo@xxxxxxxxxxxxxx are
linux-next.patch
cmpc_acpi-add-support-for-classmate-pc-acpi-devices.patch
cmpc_acpi-add-support-for-classmate-pc-acpi-devices-fix.patch
cmpc_acpi-add-support-for-classmate-pc-acpi-devices-depends-on-acpi.patch
misc-remove-mac-pmu-function-declaration-from-misc-device-class.patch
drivers-char-miscc-clear-allocation-bit-in-minor-bitmap-when-device-register-fails.patch
drivers-char-miscc-use-bitmap-bitops-functions-for-dynamic-minor-number-allocation.patch
drivers-char-miscc-use-a-proper-range-for-minor-number-dynamic-allocation.patch
spidev-use-declare_bitmap-instead-of-declaring-the-array.patch
spidev-use-declare_bitmap-instead-of-declaring-the-array-checkpatch-fixes.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
