Re: [PATCH] mtd: Allocate bdi objects dynamically

From: Richard Weinberger
Date: Sat Sep 17 2016 - 10:42:04 EST

On Thu, Aug 4, 2016 at 4:01 PM, Sandeep Jain <Sandeep_Jain@xxxxxxxxxx> wrote:
> From: Steve Longerbeam <steve_longerbeam@xxxxxxxxxx>
> 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@xxxxxxxxxx>
> Signed-off-by: Jim Baxter <jim_baxter@xxxxxxxxxx>
> Signed-off-by: Sandeep Jain <Sandeep_Jain@xxxxxxxxxx>

Reviewed-by: Richard Weinberger <richard@xxxxxx>