linux-kernel - Re: [PATCH v2 0/7] binder: eliminate use of vmalloc space for binder buffers

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Date:   Fri, 8 Feb 2019 12:26:00 +0100
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Todd Kjos <tkjos@...roid.com>
Cc:     tkjos@...gle.com, arve@...roid.com, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org, maco@...gle.com,
        joel@...lfernandes.org, kernel-team@...roid.com
Subject: Re: [PATCH v2 0/7] binder: eliminate use of vmalloc space for binder
 buffers

On Wed, Jan 30, 2019 at 02:46:48PM -0800, Todd Kjos wrote:
> Binder buffers have always been mapped into kernel space
> via map_kernel_range_noflush() to allow the binder driver
> to modify the buffer before posting to userspace for
> processing.
> 
> In recent Android releases, the number of long-running
> binder processes has increased to the point that for
> 32-bit systems, there is a risk of running out of
> vmalloc space.
> 
> This patch set removes the persistent mapping of the
> binder buffers into kernel space. Instead, the binder
> driver creates temporary mappings with kmap() or
> kmap_atomic() to copy to or from the buffer only when
> necessary.

This patch series blows up when I apply it to my char-misc-next branch:

drivers/android/binder_alloc_selftest.c: In function ‘check_buffer_pages_allocated’:
drivers/android/binder_alloc_selftest.c:108:44: error: ‘struct binder_buffer’ has no member named ‘data’
  end = (void *)PAGE_ALIGN((uintptr_t)buffer->data + size);
                                            ^~
Did you forget to enable CONFIG_ANDROID_BINDER_IPC_SELFTEST when doing your
builds?

thanks,

greg k-h