[ adding akpm, sfr, and jens ] I applied this series and pushed it out for the nvdimm.git branch that gets auto pulled into -next. The set is still awaiting acks from device-mapper, ext4, xfs, and vfs (for the copy_from_iter_ops, patch 29/33). If those come next week perhaps this can be merged for 4.12, but if not this will need to wait until 4.13. There are some minor collisions with Al's copy_from_user rework, the new dax tracepoints, and the removal of discard support from the brd driver. A sample merge is available here: https://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm.git/log/?h=libnvdimm-for-4.12-merge If it causes any other problems just drop and I'll retry for 4.13. On Mon, Apr 17, 2017 at 12:08 PM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > [ resend to add dm-devel, linux-block, and fs-devel, apologies for the > duplicates ] > > Changes since v1 [1] and the dax-fs RFC [2]: > * rename struct dax_inode to struct dax_device (Christoph) > * rewrite arch_memcpy_to_pmem() in C with inline asm > * use QUEUE_FLAG_WC to gate dax cache management (Jeff) > * add device-mapper plumbing for the ->copy_from_iter() and ->flush() > dax_operations > * kill struct blk_dax_ctl and bdev_direct_access (Christoph) > * cleanup the ->direct_access() calling convention to be page based > (Christoph) > * introduce dax_get_by_host() and don't pollute struct super_block with > dax_device details (Christoph) > > [1]: https://lists.01.org/pipermail/linux-nvdimm/2017-January/008586.html > [2]: https://lwn.net/Articles/713064/ > > --- > A few months back, in the course of reviewing the memcpy_nocache() > proposal from Brian, Linus proposed that the pmem specific > memcpy_to_pmem() routine be moved to be implemented at the driver level > [3]: > > "Quite frankly, the whole 'memcpy_nocache()' idea or (ab-)using > copy_user_nocache() just needs to die. It's idiotic. > > As you point out, it's also fundamentally buggy crap. > > Throw it away. There is no possible way this is ever valid or > portable. We're not going to lie and claim that it is. > > If some driver ends up using 'movnt' by hand, that is up to that > *driver*. But no way in hell should we care about this one whit in > the sense of <linux/uaccess.h>." > > This feedback also dovetails with another fs/dax.c design wart of being > hard coded to assume the backing device is pmem. We call the pmem > specific copy, clear, and flush routines even if the backing device > driver is one of the other 3 dax drivers (axonram, dccssblk, or brd). > There is no reason to spend cpu cycles flushing the cache after writing > to brd, for example, since it is using volatile memory for storage. > > Moreover, the pmem driver might be fronting a volatile memory range > published by the ACPI NFIT, or the platform might have arranged to flush > cpu caches on power fail. This latter capability is a feature that has > appeared in embedded storage appliances (pre-ACPI-NFIT nvdimm > platforms). > > So, this series: > > 1/ moves what was previously named "the pmem api" out of the global > namespace and into drivers that need to be concerned with > architecture specific persistent memory considerations. > > 2/ arranges for dax to stop abusing __copy_user_nocache() and implements > a libnvdimm-local memcpy that uses 'movnt' on x86_64. This might be > expanded in the future to use 'movntdqa' if the copy size is above > some threshold, or expanded with support for other architectures [4]. > > 3/ makes cache maintenance optional by arranging for dax to call driver > specific copy and flush operations only if the driver publishes them. > > 4/ allows filesytem-dax cache management to be controlled by the block > device write-cache queue flag. The pmem driver is updated to clear > that flag by default when pmem is driving volatile memory. > > [3]: https://lists.01.org/pipermail/linux-nvdimm/2017-January/008364.html > [4]: https://lists.01.org/pipermail/linux-nvdimm/2017-April/009478.html > > These patches have been through a round of build regression fixes > notified by the 0day robot. All review welcome, but the patches that > need extra attention are the device-mapper and uio changes > (copy_from_iter_ops). > > This series is based on a merge of char-misc-next (for cdev api reworks) > and libnvdimm-fixes (dax locking and __copy_user_nocache fixes). > > --- > > Dan Williams (33): > device-dax: rename 'dax_dev' to 'dev_dax' > dax: refactor dax-fs into a generic provider of 'struct dax_device' instances > dax: add a facility to lookup a dax device by 'host' device name > dax: introduce dax_operations > pmem: add dax_operations support > axon_ram: add dax_operations support > brd: add dax_operations support > dcssblk: add dax_operations support > block: kill bdev_dax_capable() > dax: introduce dax_direct_access() > dm: add dax_device and dax_operations support > dm: teach dm-targets to use a dax_device + dax_operations > ext2, ext4, xfs: retrieve dax_device for iomap operations > Revert "block: use DAX for partition table reads" > filesystem-dax: convert to dax_direct_access() > block, dax: convert bdev_dax_supported() to dax_direct_access() > block: remove block_device_operations ->direct_access() > x86, dax, pmem: remove indirection around memcpy_from_pmem() > dax, pmem: introduce 'copy_from_iter' dax operation > dm: add ->copy_from_iter() dax operation support > filesystem-dax: convert to dax_copy_from_iter() > dax, pmem: introduce an optional 'flush' dax_operation > dm: add ->flush() dax operation support > filesystem-dax: convert to dax_flush() > x86, dax: replace clear_pmem() with open coded memset + dax_ops->flush > x86, dax, libnvdimm: move wb_cache_pmem() to libnvdimm > x86, libnvdimm, pmem: move arch_invalidate_pmem() to libnvdimm > x86, libnvdimm, dax: stop abusing __copy_user_nocache > uio, libnvdimm, pmem: implement cache bypass for all copy_from_iter() operations > libnvdimm, pmem: fix persistence warning > libnvdimm, nfit: enable support for volatile ranges > filesystem-dax: gate calls to dax_flush() on QUEUE_FLAG_WC > libnvdimm, pmem: disable dax flushing when pmem is fronting a volatile region > > > MAINTAINERS | 2 > arch/powerpc/platforms/Kconfig | 1 > arch/powerpc/sysdev/axonram.c | 45 +++- > arch/x86/Kconfig | 1 > arch/x86/include/asm/pmem.h | 141 ------------ > arch/x86/include/asm/string_64.h | 1 > block/Kconfig | 1 > block/partition-generic.c | 17 - > drivers/Makefile | 2 > drivers/acpi/nfit/core.c | 15 + > drivers/block/Kconfig | 1 > drivers/block/brd.c | 52 +++- > drivers/dax/Kconfig | 10 + > drivers/dax/Makefile | 5 > drivers/dax/dax.h | 15 - > drivers/dax/device-dax.h | 25 ++ > drivers/dax/device.c | 415 +++++++++++------------------------ > drivers/dax/pmem.c | 10 - > drivers/dax/super.c | 445 ++++++++++++++++++++++++++++++++++++++ > drivers/md/Kconfig | 1 > drivers/md/dm-core.h | 1 > drivers/md/dm-linear.c | 53 ++++- > drivers/md/dm-snap.c | 6 - > drivers/md/dm-stripe.c | 65 ++++-- > drivers/md/dm-target.c | 6 - > drivers/md/dm.c | 112 ++++++++-- > drivers/nvdimm/Kconfig | 6 + > drivers/nvdimm/Makefile | 1 > drivers/nvdimm/bus.c | 10 - > drivers/nvdimm/claim.c | 9 - > drivers/nvdimm/core.c | 2 > drivers/nvdimm/dax_devs.c | 2 > drivers/nvdimm/dimm_devs.c | 2 > drivers/nvdimm/namespace_devs.c | 9 - > drivers/nvdimm/nd-core.h | 9 + > drivers/nvdimm/pfn_devs.c | 4 > drivers/nvdimm/pmem.c | 82 +++++-- > drivers/nvdimm/pmem.h | 26 ++ > drivers/nvdimm/region_devs.c | 39 ++- > drivers/nvdimm/x86.c | 155 +++++++++++++ > drivers/s390/block/Kconfig | 1 > drivers/s390/block/dcssblk.c | 44 +++- > fs/block_dev.c | 117 +++------- > fs/dax.c | 302 ++++++++++++++------------ > fs/ext2/inode.c | 9 + > fs/ext4/inode.c | 9 + > fs/iomap.c | 3 > fs/xfs/xfs_iomap.c | 10 + > include/linux/blkdev.h | 19 -- > include/linux/dax.h | 43 +++- > include/linux/device-mapper.h | 14 + > include/linux/iomap.h | 1 > include/linux/libnvdimm.h | 10 + > include/linux/pmem.h | 165 -------------- > include/linux/string.h | 8 + > include/linux/uio.h | 4 > lib/Kconfig | 6 - > lib/iov_iter.c | 25 ++ > tools/testing/nvdimm/Kbuild | 11 + > tools/testing/nvdimm/pmem-dax.c | 21 +- > 60 files changed, 1584 insertions(+), 1042 deletions(-) > delete mode 100644 arch/x86/include/asm/pmem.h > create mode 100644 drivers/dax/device-dax.h > rename drivers/dax/{dax.c => device.c} (60%) > create mode 100644 drivers/dax/super.c > create mode 100644 drivers/nvdimm/x86.c > delete mode 100644 include/linux/pmem.h
