From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53417) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fYoNR-0007Ih-Cm for qemu-devel@nongnu.org; Fri, 29 Jun 2018 04:03:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fYoNO-0006nW-8K for qemu-devel@nongnu.org; Fri, 29 Jun 2018 04:03:33 -0400 Received: from relay.sw.ru ([185.231.240.75]:58236) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fYoNN-0006ki-WE for qemu-devel@nongnu.org; Fri, 29 Jun 2018 04:03:30 -0400 From: Denis Plotnikov Date: Fri, 29 Jun 2018 11:03:15 +0300 Message-Id: <20180629080320.320144-3-dplotnikov@virtuozzo.com> In-Reply-To: <20180629080320.320144-1-dplotnikov@virtuozzo.com> References: <20180629080320.320144-1-dplotnikov@virtuozzo.com> Subject: [Qemu-devel] [PATCH v0 2/7] bitops: add some atomic versions of bitmap operations List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dgilbert@redhat.com, quintela@redhat.com, pbonzini@redhat.com Cc: qemu-devel@nongnu.org 1. test bit 2. test and set bit Signed-off-by: Denis Plotnikov --- include/qemu/bitops.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h index 3f0926cf40..7b1c8c7baf 100644 --- a/include/qemu/bitops.h +++ b/include/qemu/bitops.h @@ -94,6 +94,21 @@ static inline int test_and_set_bit(long nr, unsigned long *addr) return (old & mask) != 0; } +/** + * test_and_set_bit_atomic - Set a bit atomically and return its old value + * @nr: Bit to set + * @addr: Address to count from + */ +static inline int test_and_set_bit_atomic(long nr, unsigned long *addr) +{ + unsigned long mask = BIT_MASK(nr); + unsigned long *p = addr + BIT_WORD(nr); + unsigned long old; + + old = atomic_fetch_or(p, mask); + return (old & mask) != 0; +} + /** * test_and_clear_bit - Clear a bit and return its old value * @nr: Bit to clear @@ -134,6 +149,15 @@ static inline int test_bit(long nr, const unsigned long *addr) return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1))); } +/** + * test_bit_atomic - Determine whether a bit is set atomicallly + * @nr: bit number to test + * @addr: Address to start counting from + */ +static inline int test_bit_atomic(long nr, const unsigned long *addr) +{ + return 1UL & (atomic_read(&addr[BIT_WORD(nr)]) >> (nr & (BITS_PER_LONG-1))); +} /** * find_last_bit - find the last set bit in a memory region * @addr: The address to start the search at -- 2.17.0