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authorAkinobu Mita <akinobu.mita@gmail.com>2012-03-23 15:02:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-23 16:58:34 -0700
commit03f4a8226c2f9c14361f75848d1e93139bab90c4 (patch)
treec8c225f2debf749286c178897eaf2f802e50b0ab
parent0a329d2d5a1dd75273597538cdc33512ee38855e (diff)
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>
-rw-r--r--include/linux/bitops.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 348b1dca477a..a3b6b82108b9 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;