Hi, This is V2 of patches. I posted V1 here. https://lore.kernel.org/linux-fsdevel/20200123165249.GA7664@xxxxxxxxxx/ Changes since V1. - Took care of feedback from Christoph. - Made ->zero_page_range() mandatory operation. - Provided a generic helper to zero range for non-pmem drivers. - Merged __dax_zero_page_range() and iomap_dax_zero() - Made changes to dm drivers. - Limited range zeroing to with-in single page. - Tested patches with real hardware. description ----------- This is an RFC patch series to provide a dax operation to zero a range of memory. It will also clear poison in the process. Motivation from this patch comes from Christoph's feedback that he will rather prefer a dax way to zero a range instead of relying on having to call blkdev_issue_zeroout() in __dax_zero_page_range(). https://lkml.org/lkml/2019/8/26/361 My motivation for this change is virtiofs DAX support. There we use DAX but we don't have a block device. So any dax code which has the assumption that there is always a block device associated is a problem. So this is more of a cleanup of one of the places where dax has this dependency on block device and if we add a dax operation for zeroing a range, it can help with not having to call blkdev_issue_zeroout() in dax path. Thanks Vivek Vivek Goyal (5): dax, pmem: Add a dax operation zero_page_range s390,dax: Add dax zero_page_range operation to dcssblk driver dm,dax: Add dax zero_page_range operation dax,iomap: Start using dax native zero_page_range() dax,iomap: Add helper dax_iomap_zero() to zero a range drivers/dax/super.c | 20 ++++++++++++ drivers/md/dm-linear.c | 18 +++++++++++ drivers/md/dm-log-writes.c | 17 ++++++++++ drivers/md/dm-stripe.c | 23 ++++++++++++++ drivers/md/dm.c | 30 ++++++++++++++++++ drivers/nvdimm/pmem.c | 50 +++++++++++++++++++++++++++++ drivers/s390/block/dcssblk.c | 7 ++++ fs/dax.c | 60 ++++++++++++++--------------------- fs/iomap/buffered-io.c | 9 +----- include/linux/dax.h | 17 ++++++---- include/linux/device-mapper.h | 3 ++ 11 files changed, 204 insertions(+), 50 deletions(-) -- 2.18.1
