Skip to content
  1. Jan 09, 2014
    • John David Anglin's avatar
      parisc: Ensure full cache coherency for kmap/kunmap · f8dae006
      John David Anglin authored
      
      
      Helge Deller noted a few weeks ago problems with the AIO support on
      parisc. This change is the result of numerous iterations on how best to
      deal with this problem.
      
      The solution adopted here is to provide full cache coherency in a
      uniform manner on all parisc systems. This involves calling
      flush_dcache_page() on kmap operations and flush_kernel_dcache_page() on
      kunmap operations. As a result, the copy_user_page() and
      clear_user_page() functions can be removed and the overall code is
      simpler.
      
      The change ensures that both userspace and kernel aliases to a mapped
      page are invalidated and flushed. This is necessary for the correct
      operation of PA8800 and PA8900 based systems which do not support
      inequivalent aliases.
      
      With this change, I have observed no cache related issues on c8000 and
      rp3440. It is now possible for example to do kernel builds with "-j64"
      on four way systems.
      
      On systems using XFS file systems, the patch recently posted by Mikulas
      Patocka to "fix crash using XFS on loopback" is needed to avoid a hang
      caused by an uninitialized lock passed to flush_dcache_page() in the
      page struct.
      
      Signed-off-by: default avatarJohn David Anglin <dave.anglin@bell.net>
      Cc: stable@vger.kernel.org # v3.9+
      Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      f8dae006
  2. Jan 08, 2014
  3. Jan 07, 2014
  4. Jan 06, 2014
  5. Jan 05, 2014