Pull x86 fixes from Ingo Molnar:

 - more generic entry code ABI fallout

 - debug register handling bugfixes

 - fix vmalloc mappings on 32-bit kernels

 - kprobes instrumentation output fix on 32-bit kernels

 - fix over-eager WARN_ON_ONCE() on !SMAP hardware

 - NUMA debugging fix

 - fix Clang related crash on !RETPOLINE kernels

* tag 'x86-urgent-2020-09-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/entry: Unbreak 32bit fast syscall
  x86/debug: Allow a single level of #DB recursion
  x86/entry: Fix AC assertion
  tracing/kprobes, x86/ptrace: Fix regs argument order for i386
  x86, fakenuma: Fix invalid starting node ID
  x86/mm/32: Bring back vmalloc faulting on x86_32
  x86/cmdline: Disable jump tables for cmdline.c

Pull xen updates from Juergen Gross:
 "A small series for fixing a problem with Xen PVH guests when running
  as backends (e.g. as dom0).

  Mapping other guests' memory is now working via ZONE_DEVICE, thus not
  requiring to abuse the memory hotplug functionality for that purpose"

* tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: add helpers to allocate unpopulated memory
  memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERIC
  xen/balloon: add header guard

Pull misc fixes from Miguel Ojeda:
 "A trivial patch for auxdisplay:

   - Replace HTTP links with HTTPS ones (Alexander A. Klimov)

  The usual clang-format trivial update:

   - Update with the latest for_each macro list (Miguel Ojeda)

  And Luc requested me to pick a sparse fix on my queue, so here it goes
  along with other two trivial Compiler Attributes ones (also from Luc).

   - sparse: use static inline for __chk_{user,io}_ptr() (Luc Van
     Oostenryck)

   - Compiler Attributes: fix comment concerning GCC 4.6 (Luc Van
     Oostenryck)

   - Compiler Attributes: remove comment about sparse not supporting
     __has_attribute (Luc Van Oostenryck)"

* tag 'auxdisplay-for-linus-v5.9-rc4' of git://github.com/ojeda/linux:
  auxdisplay: Replace HTTP links with HTTPS ones

* tag 'clang-format-for-linus-v5.9-rc4' of git://github.com/ojeda/linux:
  clang-format: Update with the latest for_each macro list

* tag 'compiler-attributes-for-linus-v5.9-rc4' of git://github.com/ojeda/linux:
  sparse: use static inline for __chk_{user,io}_ptr()
  Compiler Attributes: fix comment concerning GCC 4.6
  Compiler Attributes: remove comment about sparse not supporting __has_attribute

Merge misc fixes from Andrew Morton:
 "19 patches.

  Subsystems affected by this patch series: MAINTAINERS, ipc, fork,
  checkpatch, lib, and mm (memcg, slub, pagemap, madvise, migration,
  hugetlb)"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  include/linux/log2.h: add missing () around n in roundup_pow_of_two()
  mm/khugepaged.c: fix khugepaged's request size in collapse_file
  mm/hugetlb: fix a race between hugetlb sysctl handlers
  mm/hugetlb: try preferred node first when alloc gigantic page from cma
  mm/migrate: preserve soft dirty in remove_migration_pte()
  mm/migrate: remove unnecessary is_zone_device_page() check
  mm/rmap: fixup copying of soft dirty and uffd ptes
  mm/migrate: fixup setting UFFD_WP flag
  mm: madvise: fix vma user-after-free
  checkpatch: fix the usage of capture group ( ... )
  fork: adjust sysctl_max_threads definition to match prototype
  ipc: adjust proc_ipc_sem_dointvec definition to match prototype
  mm: track page table modifications in __apply_to_page_range()
  MAINTAINERS: IA64: mark Status as Odd Fixes only
  MAINTAINERS: add LLVM maintainers
  MAINTAINERS: update Cavium/Marvell entries
  mm: slub: fix conversion of freelist_corrupted()
  mm: memcg: fix memcg reclaim soft lockup
  memcg: fix use-after-free in uncharge_batch

Otherwise gcc generates warnings if the expression is complicated.

Fixes: 312a0c170945 ("[PATCH] LOG2: Alter roundup_pow_of_two() so that it can use a ilog2() on a constant")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/0-v1-8a2697e3c003+41165-log_brackets_jgg@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull libata fixes from Jens Axboe:

 - improve Sandisks ATA_HORKAGE on NCQ (Tejun)

 - link printk cleanup (Xu)

* tag 'libata-5.9-2020-09-04' of git://git.kernel.dk/linux-block:
  libata: implement ATA_HORKAGE_MAX_TRIM_128M and apply to Sandisks
  ata: ahci: use ata_link_info() instead of ata_link_printk()

Pull block fixes from Jens Axboe:
 "A bit larger than usual this week, mostly due to the NVMe fixes
  arriving late for -rc3 and hence didn't make last weeks pull request.

   - NVMe:
        - instance leak and io boundary fixes from Keith
        - fc locking fix from Christophe
        - various tcp/rdma reset during traffic fixes from Sagi
        - pci use-after-free fix from Tong
        - tcp target null deref fix from Ziye

   - Locking fix for partition removal (Christoph)

   - Ensure bdi->io_pages is always set (me)

   - Fixup for hd struct reference (Ming)

   - Fix for zero length bvecs (Ming)

   - Two small blk-iocost fixes (Tejun)"

* tag 'block-5.9-2020-09-04' of git://git.kernel.dk/linux-block:
  block: allow for_each_bvec to support zero len bvec
  blk-stat: make q->stats->lock irqsafe
  blk-iocost: ioc_pd_free() shouldn't assume irq disabled
  block: fix locking in bdev_del_partition
  block: release disk reference in hd_struct_free_work
  block: ensure bdi->io_pages is always initialized
  nvme-pci: cancel nvme device request before disabling
  nvme: only use power of two io boundaries
  nvme: fix controller instance leak
  nvmet-fc: Fix a missed _irqsave version of spin_lock in 'nvmet_fc_fod_op_done()'
  nvme: Fix NULL dereference for pci nvme controllers
  nvme-rdma: fix reset hang if controller died in the middle of a reset
  nvme-rdma: fix timeout handler
  nvme-rdma: serialize controller teardown sequences
  nvme-tcp: fix reset hang if controller died in the middle of a reset
  nvme-tcp: fix timeout handler
  nvme-tcp: serialize controller teardown sequences
  nvme: have nvme_wait_freeze_timeout return if it timed out
  nvme-fabrics: don't check state NVME_CTRL_NEW for request acceptance
  nvmet-tcp: Fix NULL dereference when a connect data comes in h2cdata pdu

Merge emailed patches from Peter Xu:
 "This is a small series that I picked up from Linus's suggestion to
  simplify cow handling (and also make it more strict) by checking
  against page refcounts rather than mapcounts.

  This makes uffd-wp work again (verified by running upmapsort)"

Note: this is horrendously bad timing, and making this kind of
fundamental vm change after -rc3 is not at all how things should work.
The saving grace is that it really is a a nice simplification:

 8 files changed, 29 insertions(+), 120 deletions(-)

The reason for the bad timing is that it turns out that commit
17839856fd58 ("gup: document and work around 'COW can break either way'
issue" broke not just UFFD functionality (as Peter noticed), but Mikulas
Patocka also reports that it caused issues for strace when running in a
DAX environment with ext4 on a persistent memory setup.

And we can't just revert that commit without re-introducing the original
issue that is a potential security hole, so making COW stricter (and in
the process much simpler) is a step to then undoing the forced COW that
broke other uses.

Link: https://lore.kernel.org/lkml/alpine.LRH.2.02.2009031328040.6929@file01.intranet.prod.int.rdu2.redhat.com/

* emailed patches from Peter Xu <peterx@redhat.com>:
  mm: Add PGREUSE counter
  mm/gup: Remove enfornced COW mechanism
  mm/ksm: Remove reuse_ksm_page()
  mm: do_wp_page() simplification

This accounts for wp_page_reuse() case, where we reused a page for COW.

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Remove the function as the last reference has gone away with the do_wp_page()
changes.

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>