RE: [PATCH V2 08/14] Drivers: hv: balloon: Fix info request to show max page count

[Alex Ng (LIS)]

> -----Original Message-----
> From: Dan Carpenter [mailto:dan.carpenter@xxxxxxxxxx]
> Sent: Thursday, November 10, 2016 11:09 AM
> To: KY Srinivasan <kys@xxxxxxxxxxxxx>
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx; apw@xxxxxxxxxxxxx;
> vkuznets@xxxxxxxxxx; jasowang@xxxxxxxxxx;
> leann.ogasawara@xxxxxxxxxxxxx; Stephen Hemminger
> <sthemmin@xxxxxxxxxxxxx>; Alex Ng (LIS) <alexng@xxxxxxxxxxxxx>; Alex
> Ng (LIS) <alexng@xxxxxxxxxxxxx>
> Subject: Re: [PATCH V2 08/14] Drivers: hv: balloon: Fix info request to show
> max page count
> 
> On Tue, Nov 01, 2016 at 01:07:28PM -0700, kys@xxxxxxxxxxxxxxxxxxxxxx
> wrote:
> > From: Alex Ng <alexng@xxxxxxxxxxxxxxxxxxxxxx>
> >
> > Balloon driver was only printing the size of the info blob and not the
> > actual content. This fixes it so that the info blob (max page count as
> > configured in Hyper-V) is printed out.
> >
> > Signed-off-by: Alex Ng <alexng@xxxxxxxxxxxxx>
> > Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> > ---
> >  drivers/hv/hv_balloon.c |    9 +++++++--
> >  1 files changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
> > index 8cac29a..14c3dc4 100644
> > --- a/drivers/hv/hv_balloon.c
> > +++ b/drivers/hv/hv_balloon.c
> > @@ -1034,8 +1034,13 @@ static void process_info(struct
> hv_dynmem_device *dm, struct dm_info_msg *msg)
> >
> >  	switch (info_hdr->type) {
> >  	case INFO_TYPE_MAX_PAGE_CNT:
> > -		pr_info("Received INFO_TYPE_MAX_PAGE_CNT\n");
> > -		pr_info("Data Size is %d\n", info_hdr->data_size);
> > +		if (info_hdr->data_size == sizeof(__u64)) {
> > +			__u64 *max_page_count = (__u64 *)&info_hdr[1];
> 
> Why __u64 instead of u64?  Is this code shared with user space?

__u64 was being used in other parts of this code already and I decided to follow that.

I wasn't aware of this distinction between the two.
This code is not shared in user-space, so perhaps we should clean up this file in a future patch.

Thanks for bringing it up.

> 
> regards,
> dan carpenter
>