Patchwork [3/7] bitops: introduce list_for_each_clear_bit

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Submitter Akinobu Mita
Date Jan. 13, 2012, 3:53 p.m.
Message ID <1326470004-10096-4-git-send-email-akinobu.mita@gmail.com>
Download mbox | patch
Permalink /patch/135912/
State New
Headers show

Comments

Akinobu Mita - Jan. 13, 2012, 3:53 p.m.
Introduce list_for_each_clear_bit() and list_for_each_clear_bit_from().
They are similar to for_each_set_bit() and list_for_each_set_bit_from(),
but they iterate over all the cleared bits in a memory region.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: linux-s390@vger.kernel.org
Cc: linux-usb@vger.kernel.org
---
 include/linux/bitops.h |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)
Sergei Shtylyov - Jan. 13, 2012, 5:16 p.m.
Hello.

On 01/13/2012 06:53 PM, Akinobu Mita wrote:

> Introduce list_for_each_clear_bit() and list_for_each_clear_bit_from().

    It seems you've got somewhat muddled -- you're actually introducing 
for_each_clear_bit() and for_each_clear_bit_from()

> They are similar to for_each_set_bit() and list_for_each_set_bit_from(),
> but they iterate over all the cleared bits in a memory region.

> Signed-off-by: Akinobu Mita<akinobu.mita@gmail.com>
> Cc: Robert Richter<robert.richter@amd.com>
> Cc: Thomas Gleixner<tglx@linutronix.de>
> Cc: Ingo Molnar<mingo@redhat.com>
> Cc: "H. Peter Anvin"<hpa@zytor.com>
> Cc: x86@kernel.org
> Cc: David Woodhouse<dwmw2@infradead.org>
> Cc: linux-mtd@lists.infradead.org
> Cc: Martin Schwidefsky<schwidefsky@de.ibm.com>
> Cc: Heiko Carstens<heiko.carstens@de.ibm.com>
> Cc: linux390@de.ibm.com
> Cc: linux-s390@vger.kernel.org
> Cc: linux-usb@vger.kernel.org

WBR, Sergei
Akinobu Mita - Jan. 13, 2012, 11:36 p.m.
2012/1/14 Sergei Shtylyov <sshtylyov@mvista.com>:
> Hello.
>
> On 01/13/2012 06:53 PM, Akinobu Mita wrote:
>
>> Introduce list_for_each_clear_bit() and list_for_each_clear_bit_from().
>
>
>   It seems you've got somewhat muddled -- you're actually introducing
> for_each_clear_bit() and for_each_clear_bit_from()

Oops, thanks for a notification.

Patch

diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 15ad702..c8a0d65 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -32,6 +32,17 @@  extern unsigned long __sw_hweight64(__u64 w);
 	     (bit) < (size);					\
 	     (bit) = find_next_bit((addr), (size), (bit) + 1))
 
+#define for_each_clear_bit(bit, addr, size) \
+	for ((bit) = find_first_zero_bit((addr), (size));	\
+	     (bit) < (size);					\
+	     (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
+
+/* same as for_each_clear_bit() but use bit as value to start with */
+#define for_each_clear_bit_from(bit, addr, size) \
+	for ((bit) = find_next_zero_bit((addr), (size), (bit));	\
+	     (bit) < (size);					\
+	     (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
+
 static __inline__ int get_bitmask_order(unsigned int count)
 {
 	int order;