Introduce __pfn_t which:
1/ Allows kernel internal DAX mappings to adhere to the lifetime of the
the underlying block device. In general, it enables a mechanism to
allow any device driver to advertise "device memory" (CONFIG_DEV_PFN)
to other parts of the kernel.
2/ Replaces usage of struct page in struct scatterlist. A scatterlist
need only carry enough information to generate a dma address, and
removing struct page from scatterlists is a precursor to allowing DMA to
device memory. Some dma mapping implementations are not ready for a
scatterlist-pfn to reference unampped device memory, those
implementations are disabled by CONFIG_DEV_PFN=y.
Changes since v4 [1]:
1/ Drop the bio_vec conversion of struct page to __pfn_t for now. Wait
until there's a hierarchical block driver that would make use of direct
dma to pmem. (Christoph)
2/ Reorder the patch set to put the dax fixes first.
3/ Unconditionally convert struct scatterlist to use a pfn. Strictly
speaking the scatterlist conversion could also be deferred until we have
a driver that attempts dma to pmem, but struct scatterlist really has no
valid reason to carry a struct page. (Christoph)
4/ Rebased on block.git/for-next
---
Dan Williams (9):
introduce __pfn_t for scatterlists and pmem
x86: support kmap_atomic_pfn_t() for persistent memory
dax: drop size parameter to ->direct_access()
dax: fix mapping lifetime handling, convert to __pfn_t + kmap_atomic_pfn_t()
dma-mapping: allow archs to optionally specify a ->map_pfn() operation
scatterlist: use sg_phys()
scatterlist: cleanup sg_chain() and sg_unmark_end()
scatterlist: convert to __pfn_t
x86: convert dma_map_ops to support mapping a __pfn_t.
arch/Kconfig | 6 +
arch/arm/mm/dma-mapping.c | 2
arch/microblaze/kernel/dma.c | 2
arch/powerpc/sysdev/axonram.c | 26 ++++--
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 +
block/blk-merge.c | 2
drivers/block/brd.c | 9 --
drivers/block/pmem.c | 16 +++
drivers/crypto/omap-sham.c | 2
drivers/dma/imx-dma.c | 8 --
drivers/dma/ste_dma40.c | 5 -
drivers/iommu/amd_iommu.c | 21 +++--
drivers/iommu/intel-iommu.c | 26 ++++--
drivers/iommu/iommu.c | 2
drivers/mmc/card/queue.c | 4 -
drivers/pci/Kconfig | 2
drivers/s390/block/dcssblk.c | 26 +++++-
drivers/staging/android/ion/ion_chunk_heap.c | 4 -
fs/block_dev.c | 4 -
fs/dax.c | 62 +++++++++++--
include/asm-generic/dma-mapping-common.h | 30 +++++++
include/asm-generic/memory_model.h | 1
include/asm-generic/pfn.h | 120 ++++++++++++++++++++++++++
include/crypto/scatterwalk.h | 9 --
include/linux/blkdev.h | 7 +-
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 | 103 ++++++++++++++++------
include/linux/swiotlb.h | 4 +
init/Kconfig | 13 +++
lib/dma-debug.c | 10 +-
lib/swiotlb.c | 20 +++-
mm/Makefile | 1
mm/pfn.c | 98 +++++++++++++++++++++
samples/kfifo/dma-example.c | 8 +-
41 files changed, 626 insertions(+), 141 deletions(-)
create mode 100644 include/asm-generic/pfn.h
create mode 100644 mm/pfn.c
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