linux-kernel - Re: [PATCH] mtd: Allocate bdi objects dynamically

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Date:   Thu, 1 Dec 2016 10:14:00 -0800
From:   Brian Norris <computersforpeace@...il.com>
To:     Marek Vasut <marek.vasut@...il.com>
Cc:     Sandeep Jain <Sandeep_Jain@...tor.com>,
        Richard Weinberger <richard.weinberger@...il.com>,
        Steve Longerbeam <steve_longerbeam@...tor.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Jim Baxter <jim_baxter@...tor.com>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
        David Woodhouse <dwmw2@...radead.org>,
        Cyrille Pitchen <cyrille.pitchen@...el.com>
Subject: Re: [PATCH] mtd: Allocate bdi objects dynamically

On Thu, Dec 01, 2016 at 04:39:23PM +0100, Marek Vasut wrote:
> On 11/29/2016 09:12 AM, Sandeep Jain wrote:
> > On Sat, Nov 05, 2016 at 08:22:31AM +0100, Marek Vasut wrote:
> >> On 11/03/2016 12:34 PM, Sandeep Jain wrote:
> >>> On Sat, Sep 17, 2016 at 04:41:47PM +0200, Richard Weinberger wrote:
> >>>> On Thu, Aug 4, 2016 at 4:01 PM, Sandeep Jain <Sandeep_Jain@...tor.com> wrote:
> >>>>> From: Steve Longerbeam <steve_longerbeam@...tor.com>
> >>>>>
> >>>>> The MTD backing dev info objects mtd_bdi was statically allocated.
> >>>>> So when MTD is built as a loadable module, this object fall in the
> >>>>> vmalloc address space.
> >>>>>
> >>>>> The problem with that, is that the BDI APIs use wake_up_bit(), which calls
> >>>>> virt_to_page() to retrieve the memory zone of the page containing the
> >>>>> wait_queue to wake up, and virt_to_page() is not valid for vmalloc or
> >>>>> highmem addresses.
> >>>>>
> >>>>> Fix this by allocating the BDI objects dynamically with kmalloc. The
> >>>>> objects now fall in the logical address space so that BDI APIs will
> >>>>> work in all cases (mtd builtin or module).
> >>>>>
> >>>>> Signed-off-by: Steve Longerbeam <steve_longerbeam@...tor.com>
> >>>>> Signed-off-by: Jim Baxter <jim_baxter@...tor.com>
> >>>>> Signed-off-by: Sandeep Jain <Sandeep_Jain@...tor.com>
> >>>>
> >>>> Reviewed-by: Richard Weinberger <richard@....at>
> >>
> >> I don't see any obvious problem either:
> >> Reviewed-by: Marek Vasut <marek.vasut@...il.com>
> 
> Bump?

Applied to l2-mtd.git.