Hi, This RFC patchset continues my work attempting to enforce iomem safety within scatterlists. This takes a bit of a different tack from my last series [1] which tried to introduce a common scatterlist mapping function. Instead, this series takes the approach of marking SGLs that may contain unmappable memory and fencing off only the marked instances from calling sg_page and sg_virt, etc. This means we'd no longer need to clean up every SGL user in the kernel and try to deal with cases that assume every SGL always contains mappable memory with no error path. Patches 1 through 5 are cleanup/prep patches that I'll likely be submitting to their respective maintainers in short order. Patch 6 converts SGLs to use pfn_t instead of the existing page_link as suggested (and seemingly planned for) by Dan. Patches 7 and 8 then add unmappable or io memory support to SGLs Patches 9 through 14, similarly convert the bvec layer to use pfn_t Patches 15 and 16 test the above work by applying it to the nvme-fabrics code such that unmappable SGLs are being used without any BUG_ONS in somewhat limitted testing cases. Seeing this work is still incomplete and experimental, I'm looking to get feedback on people's opinions of whether this is an acceptable approach. If it is favourable, would people be open to seeing cleaned up versions of patches 6, and 9 through 14 be submitted upstream? (ie. just the parts for converting to pfn_t and continuing the unmappable/iomem/p2pmem work out-of-tree for a time). This work also opens up the possibility of having p2pmem not use ZONE_DEVICE struct pages and instead just sticking with pfn_ts with a specific p2p radix tree for looking up the backing device. Presently, I'm ambivalent towards this and would like to hear other's opinions. This series is based on v4.12-rc2 and a git tree is available here: https://github.com/sbates130272/linux-p2pmem.git io_pfn_t Thanks for your time, Logan [1] https://lkml.org/lkml/2017/4/25/738 Logan Gunthorpe (16): dmaengine: ste_dma40, imx-dma: Cleanup scatterlist layering violations staging: ccree: Cleanup: remove references to page_link kfifo: Cleanup example to not use page_link um: add dummy ioremap and iounmap functions tile: provide default ioremap declaration scatterlist: convert page_link to pfn_t scatterlist: support unmappable memory in the scatterlist scatterlist: add iomem support to sg_miter and sg_copy_* bvec: introduce bvec_page and bvec_set_page accessors bvec: massive conversion of all bv_page users bvec: convert to using pfn_t internally bvec: use sg_set_pfn when mapping a bio to an sgl block: bio: introduce bio_add_pfn block: bio: go straight from pfn_t to phys instead of through page dma-mapping: introduce and use unmappable safe sg_virt call nvmet: use unmappable sgl in rdma target arch/powerpc/sysdev/axonram.c | 2 +- arch/tile/mm/pgtable.c | 13 ++ arch/um/include/asm/io.h | 17 ++ block/bio-integrity.c | 8 +- block/bio.c | 58 +++---- block/blk-core.c | 2 +- block/blk-integrity.c | 6 +- block/blk-lib.c | 2 +- block/blk-merge.c | 10 +- block/blk-zoned.c | 6 +- block/bounce.c | 27 +-- drivers/block/aoe/aoecmd.c | 4 +- drivers/block/brd.c | 3 +- drivers/block/drbd/drbd_bitmap.c | 6 +- drivers/block/drbd/drbd_main.c | 4 +- drivers/block/drbd/drbd_receiver.c | 4 +- drivers/block/drbd/drbd_worker.c | 2 +- drivers/block/floppy.c | 4 +- drivers/block/loop.c | 12 +- drivers/block/ps3disk.c | 2 +- drivers/block/ps3vram.c | 2 +- drivers/block/rbd.c | 2 +- drivers/block/rsxx/dma.c | 3 +- drivers/block/umem.c | 2 +- drivers/block/zram/zram_drv.c | 14 +- drivers/dma/imx-dma.c | 7 +- drivers/dma/ste_dma40.c | 5 +- drivers/lightnvm/pblk-core.c | 2 +- drivers/lightnvm/pblk-read.c | 6 +- drivers/md/bcache/btree.c | 2 +- drivers/md/bcache/debug.c | 4 +- drivers/md/bcache/request.c | 4 +- drivers/md/bcache/super.c | 10 +- drivers/md/bcache/util.c | 6 +- drivers/md/dm-crypt.c | 16 +- drivers/md/dm-integrity.c | 18 +- drivers/md/dm-io.c | 2 +- drivers/md/dm-log-writes.c | 12 +- drivers/md/dm-verity-target.c | 4 +- drivers/md/raid5.c | 10 +- drivers/memstick/core/mspro_block.c | 2 +- drivers/nvdimm/blk.c | 4 +- drivers/nvdimm/btt.c | 5 +- drivers/nvdimm/pmem.c | 2 +- drivers/nvme/host/core.c | 2 +- drivers/nvme/host/nvme.h | 2 +- drivers/nvme/host/pci.c | 5 +- drivers/nvme/target/Kconfig | 12 ++ drivers/nvme/target/io-cmd.c | 2 +- drivers/nvme/target/rdma.c | 29 +++- 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 | 2 +- drivers/s390/block/scm_blk.c | 2 +- drivers/s390/block/scm_blk_cluster.c | 2 +- drivers/s390/block/xpram.c | 2 +- drivers/scsi/mpt3sas/mpt3sas_transport.c | 6 +- drivers/scsi/sd.c | 16 +- drivers/scsi/sd_dif.c | 4 +- drivers/staging/ccree/ssi_buffer_mgr.c | 17 +- .../staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c | 4 +- .../lustre/lnet/klnds/socklnd/socklnd_lib.c | 10 +- drivers/staging/lustre/lnet/lnet/lib-move.c | 4 +- drivers/staging/lustre/lnet/lnet/router.c | 6 +- drivers/staging/lustre/lnet/selftest/brw_test.c | 4 +- drivers/staging/lustre/lnet/selftest/conrpc.c | 10 +- drivers/staging/lustre/lnet/selftest/framework.c | 2 +- drivers/staging/lustre/lnet/selftest/rpc.c | 4 +- drivers/staging/lustre/lustre/include/lustre_net.h | 2 +- drivers/staging/lustre/lustre/osc/osc_page.c | 2 +- drivers/staging/lustre/lustre/ptlrpc/client.c | 2 +- drivers/staging/lustre/lustre/ptlrpc/sec_bulk.c | 6 +- drivers/staging/lustre/lustre/ptlrpc/sec_plain.c | 4 +- drivers/target/target_core_file.c | 4 +- drivers/xen/biomerge.c | 4 +- fs/9p/vfs_addr.c | 6 +- fs/afs/rxrpc.c | 4 +- fs/block_dev.c | 8 +- fs/btrfs/check-integrity.c | 4 +- fs/btrfs/compression.c | 14 +- fs/btrfs/disk-io.c | 4 +- fs/btrfs/extent_io.c | 8 +- fs/btrfs/file-item.c | 8 +- fs/btrfs/inode.c | 14 +- fs/btrfs/raid56.c | 4 +- fs/buffer.c | 2 +- fs/cifs/connect.c | 3 +- fs/cifs/file.c | 6 +- fs/cifs/misc.c | 2 +- fs/cifs/smb2ops.c | 2 +- fs/cifs/transport.c | 3 +- fs/crypto/bio.c | 2 +- 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 | 2 +- fs/f2fs/data.c | 12 +- fs/gfs2/lops.c | 4 +- fs/gfs2/meta_io.c | 2 +- fs/iomap.c | 2 +- fs/mpage.c | 2 +- fs/orangefs/inode.c | 3 +- fs/splice.c | 2 +- fs/xfs/xfs_aops.c | 2 +- include/linux/bio.h | 34 +++- include/linux/bvec.h | 21 ++- include/linux/dma-mapping.h | 9 +- include/linux/pfn_t.h | 42 ++++- include/linux/scatterlist.h | 189 +++++++++++++++------ kernel/power/swap.c | 2 +- lib/Kconfig | 11 ++ lib/iov_iter.c | 24 +-- lib/scatterlist.c | 65 ++++++- mm/page_io.c | 8 +- net/ceph/messenger.c | 6 +- samples/kfifo/dma-example.c | 8 +- 118 files changed, 690 insertions(+), 393 deletions(-) create mode 100644 arch/um/include/asm/io.h -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
