Commit 03f4a822 authored Mar 23, 2012 by Akinobu Mita Committed by Linus Torvalds Mar 23, 2012

bitops: introduce for_each_clear_bit()

Introduce 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: David Woodhouse <dwmw2@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Stefano Panella <stefano.panella@csr.com>
Cc: David Vrabel <david.vrabel@csr.com>
Cc: Sergei Shtylyov <sshtylyov@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 0a329d2d

include/linux/bitops.h

+11 −0

Original line number	Diff line number	Diff line
		@@ -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;

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