From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48302) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fdXmx-0004zh-32 for qemu-devel@nongnu.org; Thu, 12 Jul 2018 05:21:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fdXms-0006YZ-4Q for qemu-devel@nongnu.org; Thu, 12 Jul 2018 05:21:27 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:51640 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fdXmr-0006XW-Us for qemu-devel@nongnu.org; Thu, 12 Jul 2018 05:21:22 -0400 Date: Thu, 12 Jul 2018 10:21:17 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20180712092117.GC2610@work-vm> References: <20180629080320.320144-1-dplotnikov@virtuozzo.com> <20180629080320.320144-3-dplotnikov@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180629080320.320144-3-dplotnikov@virtuozzo.com> Subject: Re: [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: Denis Plotnikov Cc: quintela@redhat.com, pbonzini@redhat.com, qemu-devel@nongnu.org * Denis Plotnikov (dplotnikov@virtuozzo.com) wrote: > 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))); Note that fails the style check because it's expecting spaces around the '-', (which would then take you over 80 chars); your patch is consistent with the other places in the file though. It's probably best if you make the style checker happy. So, Reviewed-by: Dr. David Alan Gilbert > +} > /** > * find_last_bit - find the last set bit in a memory region > * @addr: The address to start the search at > -- > 2.17.0 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK