[PATCH 1/3] hv: hv_util: move vmbus_open() to a later place

[PATCH 1/3] hv: hv_util: move vmbus_open() to a later place

[Dexuan Cui]

Before the line vmbus_open() returns, srv->util_cb can be already running
and the variablies, like util_fw_version, are needed by the srv->util_cb.

So we have to make sure the variables are initialized before the vmbus_open().

CC: "K. Y. Srinivasan" <kys@microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
 drivers/hv/hv_util.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 3b9c9ef..c5be773 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -340,12 +340,8 @@ static int util_probe(struct hv_device *dev,
 
 	set_channel_read_state(dev->channel, false);
 
-	ret = vmbus_open(dev->channel, 4 * PAGE_SIZE, 4 * PAGE_SIZE, NULL, 0,
-			srv->util_cb, dev->channel);
-	if (ret)
-		goto error;
-
 	hv_set_drvdata(dev, srv);
+
 	/*
 	 * Based on the host; initialize the framework and
 	 * service version numbers we will negotiate.
@@ -365,6 +361,11 @@ static int util_probe(struct hv_device *dev,
 		hb_srv_version = HB_VERSION;
 	}
 
+	ret = vmbus_open(dev->channel, 4 * PAGE_SIZE, 4 * PAGE_SIZE, NULL, 0,
+			srv->util_cb, dev->channel);
+	if (ret)
+		goto error;
+
 	return 0;
 
 error:
-- 
1.9.1

Re: [PATCH 1/3] hv: hv_util: move vmbus_open() to a later place

[Vitaly Kuznetsov]

Dexuan Cui <decui@microsoft.com> writes:

> Before the line vmbus_open() returns, srv->util_cb can be already running
> and the variablies, like util_fw_version, are needed by the srv->util_cb.
>
> So we have to make sure the variables are initialized before the vmbus_open().
>
> CC: "K. Y. Srinivasan" <kys@microsoft.com>
> Signed-off-by: Dexuan Cui <decui@microsoft.com>

It is not said in the description but moving hv_set_drvdata() before
vmbus_open() make sense in case probe and remove can collide (can
they?).

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>

> ---
>  drivers/hv/hv_util.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
> index 3b9c9ef..c5be773 100644
> --- a/drivers/hv/hv_util.c
> +++ b/drivers/hv/hv_util.c
> @@ -340,12 +340,8 @@ static int util_probe(struct hv_device *dev,
>
>  	set_channel_read_state(dev->channel, false);
>
> -	ret = vmbus_open(dev->channel, 4 * PAGE_SIZE, 4 * PAGE_SIZE, NULL, 0,
> -			srv->util_cb, dev->channel);
> -	if (ret)
> -		goto error;
> -
>  	hv_set_drvdata(dev, srv);
> +
>  	/*
>  	 * Based on the host; initialize the framework and
>  	 * service version numbers we will negotiate.
> @@ -365,6 +361,11 @@ static int util_probe(struct hv_device *dev,
>  		hb_srv_version = HB_VERSION;
>  	}
>
> +	ret = vmbus_open(dev->channel, 4 * PAGE_SIZE, 4 * PAGE_SIZE, NULL, 0,
> +			srv->util_cb, dev->channel);
> +	if (ret)
> +		goto error;
> +
>  	return 0;
>
>  error:

-- 
  Vitaly

RE: [PATCH 1/3] hv: hv_util: move vmbus_open() to a later place

[Dexuan Cui]

> -----Original Message-----
> From: Vitaly Kuznetsov [mailto:vkuznets@redhat.com]
> Sent: Thursday, January 29, 2015 21:13 PM
> To: Dexuan Cui
> Cc: gregkh@linuxfoundation.org; linux-kernel@vger.kernel.org; driverdev-
> devel@linuxdriverproject.org; olaf@aepfle.de; apw@canonical.com;
> jasowang@redhat.com; KY Srinivasan; Haiyang Zhang
> Subject: Re: [PATCH 1/3] hv: hv_util: move vmbus_open() to a later place
> 
> Dexuan Cui <decui@microsoft.com> writes:
> 
> > Before the line vmbus_open() returns, srv->util_cb can be already running
> > and the variablies, like util_fw_version, are needed by the srv->util_cb.
> >
> > So we have to make sure the variables are initialized before the vmbus_open().
> >
> > CC: "K. Y. Srinivasan" <kys@microsoft.com>
> > Signed-off-by: Dexuan Cui <decui@microsoft.com>
> 
> It is not said in the description but moving hv_set_drvdata() before
> vmbus_open() make sense in case probe and remove can collide (can
> they?).
I'm not so sure. In normal usages, the collision should be unlikely.
Anyway, the patch makes things better. :-)

> 
> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Thanks for the review!

Thanks,
-- Dexuan

> > ---
> >  drivers/hv/hv_util.c | 11 ++++++-----
> >  1 file changed, 6 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
> > index 3b9c9ef..c5be773 100644
> > --- a/drivers/hv/hv_util.c
> > +++ b/drivers/hv/hv_util.c
> > @@ -340,12 +340,8 @@ static int util_probe(struct hv_device *dev,
> >
> >  	set_channel_read_state(dev->channel, false);
> >
> > -	ret = vmbus_open(dev->channel, 4 * PAGE_SIZE, 4 * PAGE_SIZE, NULL, 0,
> > -			srv->util_cb, dev->channel);
> > -	if (ret)
> > -		goto error;
> > -
> >  	hv_set_drvdata(dev, srv);
> > +
> >  	/*
> >  	 * Based on the host; initialize the framework and
> >  	 * service version numbers we will negotiate.
> > @@ -365,6 +361,11 @@ static int util_probe(struct hv_device *dev,
> >  		hb_srv_version = HB_VERSION;
> >  	}
> >
> > +	ret = vmbus_open(dev->channel, 4 * PAGE_SIZE, 4 * PAGE_SIZE, NULL, 0,
> > +			srv->util_cb, dev->channel);
> > +	if (ret)
> > +		goto error;
> > +
> >  	return 0;
> >
> >  error:
> 
> --
>   Vitaly