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

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Message-ID: <20161103113421.GA4873@mentor.com>
Date:   Thu, 3 Nov 2016 17:04:22 +0530
From:   Sandeep Jain <Sandeep_Jain@...tor.com>
To:     Richard Weinberger <richard.weinberger@...il.com>
CC:     David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Steve Longerbeam <steve_longerbeam@...tor.com>,
        Jim Baxter <jim_baxter@...tor.com>
Subject: Re: [PATCH] mtd: Allocate bdi objects dynamically

Dear Maintainers,
  This patch is reviewed by Richard.
Requesting for Maintainer's attention for patch merge.

Thanks & Regards,
Sandeep Jain

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>
> 
> -- 
> Thanks,
> //richard