[PATCH v3 00/11] evacuate struct page from the block layer, introduce __pfn_t

From: Dan Williams
Date: Tue May 12 2015 - 00:32:22 EST


Changes since v2 [1]:
[1]: https://lwn.net/Articles/643437/

1/ Linus pointed out that comparing a __pfn_t value against PAGE_OFFSET
was both inefficient, when PAGE_OFFSET is a large constant, and
incorrect for archs that set PAGE_OFFSET to zero. Instead, take
advantage of the standard alignment of a 'struct page *' to store a set
of flags. In this patch set the only flag defined is PFN_DEV to
indicate "this pfn originated from device memory". A potential future
flag is PFN_DEV_MAPPED if the device has arranged for an associated
struct page for the __pfn_t.

2/ Fix DAX against pmem device disable/removal using
kmap_atomic_pfn_t(). We can later exploit these annotations to protect
against the "stray pointer problem" whereby a kernel bug in an unrelated
part of the system causes inadvertent scribbling over pmem.

3/ Made the series easier to merge as it no longer causes compile errors
by default for new usages of bv_page arriving in the next merge window.

4/ arch/x86/kernel/kmap.c => mm/pfn.c since it is generic functionality.

5/ Updated the kmap_atomic() helpers in bio.h to use kmap_atomic_pfn_t()

Incremental diffstat:

arch/powerpc/sysdev/axonram.c | 9 +++++--
arch/x86/Kconfig | 2 +-
arch/x86/kernel/Makefile | 1 -
block/bio.c | 4 +--
block/blk-core.c | 2 +-
drivers/block/brd.c | 3 +--
drivers/block/pmem.c | 9 ++++---
drivers/s390/block/dcssblk.c | 11 +++++---
fs/block_dev.c | 4 +--
fs/dax.c | 57 ++++++++++++++++++++++++++++++++--------
include/asm-generic/pfn.h | 73 ++++++++++++++++++++++++++++++++++------------------
include/linux/bio.h | 14 +++++-----
include/linux/blk_types.h | 2 +-
include/linux/blkdev.h | 7 +++--
init/Kconfig | 12 ++++-----
mm/Makefile | 1 +
arch/x86/kernel/kmap.c => mm/pfn.c | 0
17 files changed, 140 insertions(+), 71 deletions(-)
rename arch/x86/kernel/kmap.c => mm/pfn.c (100%)

While we wait for the debate [2] to settle about what to do about i/o
paths that ostensibly require struct page, these patches enable a
stacked/tiered storage driver to manage pmem fronting slower storage
media.

[2]: https://lists.01.org/pipermail/linux-nvdimm/2015-May/000727.html

---

Dan Williams (10):
arch: introduce __pfn_t for persistenti/device memory
block: add helpers for accessing a bio_vec page
block: convert .bv_page to .bv_pfn bio_vec
dma-mapping: allow archs to optionally specify a ->map_pfn() operation
scatterlist: use sg_phys()
x86: support dma_map_pfn()
x86: support kmap_atomic_pfn_t() for persistent memory
block: convert kmap helpers to kmap_atomic_pfn_t()
dax: convert to __pfn_t
block: base support for pfn i/o

Matthew Wilcox (1):
scatterlist: support "page-less" (__pfn_t only) entries


Documentation/block/biodoc.txt | 4 +
arch/Kconfig | 6 ++
arch/arm/mm/dma-mapping.c | 2 -
arch/microblaze/kernel/dma.c | 2 -
arch/powerpc/sysdev/axonram.c | 13 ++-
arch/x86/Kconfig | 7 ++
arch/x86/kernel/amd_gart_64.c | 22 +++++-
arch/x86/kernel/pci-nommu.c | 22 +++++-
arch/x86/kernel/pci-swiotlb.c | 4 +
arch/x86/pci/sta2x11-fixup.c | 4 +
arch/x86/xen/pci-swiotlb-xen.c | 4 +
block/bio-integrity.c | 8 +-
block/bio.c | 82 +++++++++++++++-------
block/blk-core.c | 13 +++
block/blk-integrity.c | 7 +-
block/blk-lib.c | 2 -
block/blk-merge.c | 15 ++--
block/bounce.c | 26 +++----
drivers/block/aoe/aoecmd.c | 8 +-
drivers/block/brd.c | 7 +-
drivers/block/drbd/drbd_bitmap.c | 5 +
drivers/block/drbd/drbd_main.c | 6 +-
drivers/block/drbd/drbd_receiver.c | 4 +
drivers/block/drbd/drbd_worker.c | 3 +
drivers/block/floppy.c | 6 +-
drivers/block/loop.c | 13 ++-
drivers/block/nbd.c | 8 +-
drivers/block/nvme-core.c | 2 -
drivers/block/pktcdvd.c | 11 ++-
drivers/block/pmem.c | 19 ++++-
drivers/block/ps3disk.c | 2 -
drivers/block/ps3vram.c | 2 -
drivers/block/rbd.c | 2 -
drivers/block/rsxx/dma.c | 2 -
drivers/block/umem.c | 2 -
drivers/block/zram/zram_drv.c | 10 +--
drivers/dma/ste_dma40.c | 5 -
drivers/iommu/amd_iommu.c | 21 ++++--
drivers/iommu/intel-iommu.c | 26 +++++--
drivers/iommu/iommu.c | 2 -
drivers/md/bcache/btree.c | 4 +
drivers/md/bcache/debug.c | 6 +-
drivers/md/bcache/movinggc.c | 2 -
drivers/md/bcache/request.c | 6 +-
drivers/md/bcache/super.c | 10 +--
drivers/md/bcache/util.c | 5 +
drivers/md/bcache/writeback.c | 2 -
drivers/md/dm-crypt.c | 12 ++-
drivers/md/dm-io.c | 2 -
drivers/md/dm-log-writes.c | 14 ++--
drivers/md/dm-verity.c | 2 -
drivers/md/raid1.c | 50 +++++++------
drivers/md/raid10.c | 38 +++++-----
drivers/md/raid5.c | 6 +-
drivers/mmc/card/queue.c | 4 +
drivers/s390/block/dasd_diag.c | 2 -
drivers/s390/block/dasd_eckd.c | 14 ++--
drivers/s390/block/dasd_fba.c | 6 +-
drivers/s390/block/dcssblk.c | 15 +++-
drivers/s390/block/scm_blk.c | 2 -
drivers/s390/block/scm_blk_cluster.c | 2 -
drivers/s390/block/xpram.c | 2 -
drivers/scsi/mpt2sas/mpt2sas_transport.c | 6 +-
drivers/scsi/mpt3sas/mpt3sas_transport.c | 6 +-
drivers/scsi/sd_dif.c | 4 +
drivers/staging/android/ion/ion_chunk_heap.c | 4 +
drivers/staging/lustre/lustre/llite/lloop.c | 2 -
drivers/target/target_core_file.c | 4 +
drivers/xen/biomerge.c | 4 +
drivers/xen/swiotlb-xen.c | 29 +++++---
fs/9p/vfs_addr.c | 2 -
fs/block_dev.c | 4 +
fs/btrfs/check-integrity.c | 6 +-
fs/btrfs/compression.c | 12 ++-
fs/btrfs/disk-io.c | 5 +
fs/btrfs/extent_io.c | 8 +-
fs/btrfs/file-item.c | 8 +-
fs/btrfs/inode.c | 19 +++--
fs/btrfs/raid56.c | 4 +
fs/btrfs/volumes.c | 2 -
fs/buffer.c | 4 +
fs/dax.c | 62 +++++++++++++---
fs/direct-io.c | 2 -
fs/exofs/ore.c | 4 +
fs/exofs/ore_raid.c | 2 -
fs/ext4/page-io.c | 2 -
fs/ext4/readpage.c | 4 +
fs/f2fs/data.c | 4 +
fs/f2fs/segment.c | 2 -
fs/gfs2/lops.c | 4 +
fs/jfs/jfs_logmgr.c | 4 +
fs/logfs/dev_bdev.c | 10 +--
fs/mpage.c | 2 -
fs/splice.c | 2 -
include/asm-generic/dma-mapping-common.h | 30 ++++++++
include/asm-generic/memory_model.h | 1
include/asm-generic/pfn.h | 95 +++++++++++++++++++++++++
include/asm-generic/scatterlist.h | 10 +++
include/crypto/scatterwalk.h | 10 +++
include/linux/bio.h | 28 ++++---
include/linux/blk_types.h | 31 ++++++++
include/linux/blkdev.h | 9 +-
include/linux/dma-debug.h | 23 +++++-
include/linux/dma-mapping.h | 8 ++
include/linux/highmem.h | 23 ++++++
include/linux/mm.h | 1
include/linux/scatterlist.h | 91 ++++++++++++++++++++++--
include/linux/swiotlb.h | 4 +
init/Kconfig | 13 +++
kernel/power/block_io.c | 2 -
lib/dma-debug.c | 10 ++-
lib/iov_iter.c | 22 +++---
lib/swiotlb.c | 20 ++++-
mm/Makefile | 1
mm/page_io.c | 10 +--
mm/pfn.c | 98 ++++++++++++++++++++++++++
net/ceph/messenger.c | 2 -
117 files changed, 1003 insertions(+), 391 deletions(-)
create mode 100644 include/asm-generic/pfn.h
create mode 100644 mm/pfn.c
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