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Date:   Thu, 27 Oct 2022 13:22:07 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Wei Liu <wei.liu@kernel.org>
Cc:     Shradha Gupta <shradhagupta@linux.microsoft.com>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        linux-hyperv@vger.kernel.org,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Dexuan Cui <decui@microsoft.com>,
        Michael Kelley <mikelley@microsoft.com>
Subject: Re: [PATCH v2 1/2] mm/page_reporting: Add checks for
 page_reporting_order param
Message-Id: <20221027132207.bb4e9408e1ca94b3dfaca405@linux-foundation.org>
In-Reply-To: <Y1lTWxMnk3lnS+3V@liuwe-devbox-debian-v2>
References: <1664447081-14744-1-git-send-email-shradhagupta@linux.microsoft.com>
        <1664517699-1085-1-git-send-email-shradhagupta@linux.microsoft.com>
        <1664517699-1085-2-git-send-email-shradhagupta@linux.microsoft.com>
        <Y1lTWxMnk3lnS+3V@liuwe-devbox-debian-v2>
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On Wed, 26 Oct 2022 15:33:47 +0000 Wei Liu <wei.liu@kernel.org> wrote:

> On Thu, Sep 29, 2022 at 11:01:38PM -0700, Shradha Gupta wrote:
> > Current code allows the page_reporting_order parameter to be changed
> > via sysfs to any integer value.  The new value is used immediately
> > in page reporting code with no validation, which could cause incorrect
> > behavior.  Fix this by adding validation of the new value.
> > Export this parameter for use in the driver that is calling the
> > page_reporting_register().
> > This is needed by drivers like hv_balloon to know the order of the
> > pages reported. Traditionally the values provided in the kernel boot
> > line or subsequently changed via sysfs take priority therefore, if
> > page_reporting_order parameter's value is set, it takes precedence
> > over the value passed while registering with the driver.
> > 
> > Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
> 
> Andrew and other MM reviewers, can I get an ack / nack for this patch?

Looks OK to me.  Can this be merged via the hyperv tree?