From 36546e5b803f6e363906607307f27c489441fd15 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Tue, 2 Dec 2014 11:23:15 +0000 Subject: bitmap: add atomic test and clear The new bitmap_test_and_clear_atomic() function clears a range and returns whether or not the bits were set. Signed-off-by: Stefan Hajnoczi Message-Id: <1417519399-3166-3-git-send-email-stefanha@redhat.com> [Test before xchg; then a full barrier is needed at the end just like in the previous patch. The barrier can be avoided if we did at least one xchg. - Paolo] Reviewed-by: Fam Zheng Signed-off-by: Paolo Bonzini --- include/qemu/bitmap.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/qemu/bitmap.h b/include/qemu/bitmap.h index 3e0a4f3e0c..86dd9cd5fc 100644 --- a/include/qemu/bitmap.h +++ b/include/qemu/bitmap.h @@ -41,6 +41,7 @@ * bitmap_set(dst, pos, nbits) Set specified bit area * bitmap_set_atomic(dst, pos, nbits) Set specified bit area with atomic ops * bitmap_clear(dst, pos, nbits) Clear specified bit area + * bitmap_test_and_clear_atomic(dst, pos, nbits) Test and clear area * bitmap_find_next_zero_area(buf, len, pos, n, mask) Find bit free area */ @@ -229,6 +230,7 @@ static inline int bitmap_intersects(const unsigned long *src1, void bitmap_set(unsigned long *map, long i, long len); void bitmap_set_atomic(unsigned long *map, long i, long len); void bitmap_clear(unsigned long *map, long start, long nr); +bool bitmap_test_and_clear_atomic(unsigned long *map, long start, long nr); unsigned long bitmap_find_next_zero_area(unsigned long *map, unsigned long size, unsigned long start, -- cgit v1.2.3