From: Greg KH <gregkh@linuxfoundation.org>
To: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: linux-kernel@vger.kernel.org, devel@linuxdriverproject.org,
olaf@aepfle.de, apw@canonical.com, vkuznets@redhat.com,
jasowang@redhat.com, stable@vger.kernel.org
Subject: Re: [PATCH 3/7] Drivers: hv: vmbus: Fix a bug in hv_need_to_signal_on_read()
Date: Thu, 31 Mar 2016 17:00:17 -0700 [thread overview]
Message-ID: <20160401000017.GB10232@kroah.com> (raw)
In-Reply-To: <1458780837-4367-3-git-send-email-kys@microsoft.com>
On Wed, Mar 23, 2016 at 05:53:53PM -0700, K. Y. Srinivasan wrote:
> We need to issue a full memory barrier prior making a signalling decision.
>
> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
> Cc: stable@vger.kernel.org
> ---
> drivers/hv/ring_buffer.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
> index 2919395..67dc245 100644
> --- a/drivers/hv/ring_buffer.c
> +++ b/drivers/hv/ring_buffer.c
> @@ -104,6 +104,7 @@ static bool hv_need_to_signal_on_read(struct hv_ring_buffer_info *rbi)
> u32 cur_write_sz;
> u32 pending_sz;
>
> + mb();
And, are you sure this is correct? You better document the heck out of
this, why it's here, and what it is protecting. "raw" mb() calls are
really rare for good reason.
thanks,
greg k-h
next prev parent reply other threads:[~2016-04-01 0:00 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-24 0:53 [PATCH 0/7] Drivers: hv: vmbus: Cleanup the ring buffer code K. Y. Srinivasan
2016-03-24 0:53 ` [PATCH 1/7] Drivers: hv: vmbus: Introduce functions for estimating room in the ring buffer K. Y. Srinivasan
2016-03-24 0:53 ` [PATCH 2/7] Drivers: hv: vmbus: Use READ_ONCE() to read variables that are volatile K. Y. Srinivasan
2016-04-01 0:00 ` Greg KH
2016-04-01 22:02 ` KY Srinivasan
2016-03-24 0:53 ` [PATCH 3/7] Drivers: hv: vmbus: Fix a bug in hv_need_to_signal_on_read() K. Y. Srinivasan
2016-03-31 23:59 ` Greg KH
2016-04-01 21:03 ` KY Srinivasan
2016-04-01 0:00 ` Greg KH [this message]
2016-04-01 21:57 ` KY Srinivasan
2016-03-24 0:53 ` [PATCH 4/7] Drivers: hv: vmbus: Use the new virt_xx barrier code K. Y. Srinivasan
2016-03-24 0:53 ` [PATCH 5/7] Drivers: hv: vmbus: Export the vmbus_set_event() API K. Y. Srinivasan
2016-03-24 0:53 ` [PATCH 6/7] Drivers: hv: vmbus: Move some ring buffer functions to hyperv.h K. Y. Srinivasan
2016-03-24 0:53 ` [PATCH 7/7] Drivers: hv: vmbus: Implement APIs to support "in place" consumption of vmbus packets K. Y. Srinivasan
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