On Mon, Apr 10, 2017 at 05:35:02PM -0700, Dan Williams wrote: > Before we rework the "pmem api" to stop abusing __copy_user_nocache() > for memcpy_to_pmem() we need to fix cases where we may strand dirty data > in the cpu cache. The problem occurs when copy_from_iter_pmem() is used > for arbitrary data transfers from userspace. There is no guarantee that > these transfers, performed by dax_iomap_actor(), will have aligned > destinations or aligned transfer lengths. Backstop the usage > __copy_user_nocache() with explicit cache management in these unaligned > cases. > > Yes, copy_from_iter_pmem() is now too big for an inline, but addressing > that is saved for a later patch that moves the entirety of the "pmem > api" into the pmem driver directly. > > Fixes: 5de490daec8b ("pmem: add copy_from_iter_pmem() and clear_pmem()") > Cc: <stable@xxxxxxxxxxxxxxx> > Cc: <x86@xxxxxxxxxx> > Cc: Jan Kara <jack@xxxxxxx> > Cc: Jeff Moyer <jmoyer@xxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: Christoph Hellwig <hch@xxxxxx> > Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> > Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> > Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> > Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> This looks good to me, thanks for fixing this. Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>