linux-kernel - RE: [PATCH 03/15] hyperv: use standard bitops

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Message-ID: <DM5PR03MB2490D5F2E1D208D674A5FFB1A0930@DM5PR03MB2490.namprd03.prod.outlook.com>
Date:   Wed, 21 Dec 2016 19:08:24 +0000
From:   KY Srinivasan <kys@...rosoft.com>
To:     Roman Kagan <rkagan@...tuozzo.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>
CC:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "Haiyang Zhang" <haiyangz@...rosoft.com>,
        "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "devel@...uxdriverproject.org" <devel@...uxdriverproject.org>,
        "Denis V . Lunev" <den@...nvz.org>
Subject: RE: [PATCH 03/15] hyperv: use standard bitops



> -----Original Message-----
> From: Roman Kagan [mailto:rkagan@...tuozzo.com]
> Sent: Tuesday, December 20, 2016 7:56 AM
> To: Paolo Bonzini <pbonzini@...hat.com>; Radim Krčmář
> <rkrcmar@...hat.com>; KY Srinivasan <kys@...rosoft.com>; Vitaly
> Kuznetsov <vkuznets@...hat.com>
> Cc: Thomas Gleixner <tglx@...utronix.de>; Ingo Molnar
> <mingo@...hat.com>; H. Peter Anvin <hpa@...or.com>; x86@...nel.org;
> Haiyang Zhang <haiyangz@...rosoft.com>; kvm@...r.kernel.org; linux-
> kernel@...r.kernel.org; devel@...uxdriverproject.org; Denis V . Lunev
> <den@...nvz.org>; Roman Kagan <rkagan@...tuozzo.com>
> Subject: [PATCH 03/15] hyperv: use standard bitops
>
No commit log?
 
> Signed-off-by: Roman Kagan <rkagan@...tuozzo.com>
> ---
>  drivers/hv/channel.c    | 8 +++-----
>  drivers/hv/connection.c | 9 +++------
>  2 files changed, 6 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
> index 5fb4c6d..f9df275 100644
> --- a/drivers/hv/channel.c
> +++ b/drivers/hv/channel.c
> @@ -49,15 +49,13 @@ void vmbus_setevent(struct vmbus_channel
> *channel)
>  	 */
>  	if ((channel->offermsg.monitor_allocated) &&
>  	    (!channel->low_latency)) {
> -		/* Each u32 represents 32 channels */
> -		sync_set_bit(channel->offermsg.child_relid & 31,
> -			(unsigned long *) vmbus_connection.send_int_page
> +
> -			(channel->offermsg.child_relid >> 5));
> +		set_bit(channel->offermsg.child_relid,
> +			(unsigned long
> *)vmbus_connection.send_int_page);
>
What is the rationale for dropping the sync variant?
 
>  		/* Get the child to parent monitor page */
>  		monitorpage = vmbus_connection.monitor_pages[1];
> 
> -		sync_set_bit(channel->monitor_bit,
> +		set_bit(channel->monitor_bit,
>  			(unsigned long *)&monitorpage->trigger_group
>  					[channel->monitor_grp].pending);
> 
Same comment as before.
> diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
> index aaa2103..139b33e 100644
> --- a/drivers/hv/connection.c
> +++ b/drivers/hv/connection.c
> @@ -468,12 +468,9 @@ void vmbus_set_event(struct vmbus_channel
> *channel)
>  {
>  	u32 child_relid = channel->offermsg.child_relid;
> 
> -	if (!channel->is_dedicated_interrupt) {
> -		/* Each u32 represents 32 channels */
> -		sync_set_bit(child_relid & 31,
> -			(unsigned long *)vmbus_connection.send_int_page
> +
> -			(child_relid >> 5));
> -	}
> +	if (!channel->is_dedicated_interrupt)
> +		set_bit(child_relid,
> +			(unsigned long
> *)vmbus_connection.send_int_page);
> 
>  	hv_do_hypercall(HVCALL_SIGNAL_EVENT, channel->sig_event,
> NULL);
>  }
> --
> 2.9.3