On Wed, Mar 02, 2016 at 10:15:02AM +0100, Arnd Bergmann wrote:
I'm missing the background on this, just saw the patch fly by,
so sorry if this has been asked before:
Why do you want to invalidate the cache? Is this to save RAM
or is something else going to write here and you have to invalidate
it for correctness?
BLKZEROOUT can be though as a direct I/O operation - it issues a
WRITE SAME (or similar) command straight to the device to zero
the specified range. If there was cached data for this range it would
now be stale.