This prepares for the future work to trigger early cow on pinned pages
during fork().

No functional change intended.

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

(Commit message majorly collected from Jason Gunthorpe)

Reduce the chance of false positive from page_maybe_dma_pinned() by
keeping track if the mm_struct has ever been used with pin_user_pages().
This allows cases that might drive up the page ref_count to avoid any
penalty from handling dma_pinned pages.

Future work is planned, to provide a more sophisticated solution, likely
to turn it into a real counter.  For now, make it atomic_t but use it as
a boolean for simplicity.

Suggested-by: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull power management fixes from Rafael Wysocki:
 "These fix more fallout of recent RCU-lockdep changes in CPU idle code
  and two devfreq issues.

  Specifics:

   - Export rcu_idle_{enter,exit} to modules to fix build issues
     introduced by recent RCU-lockdep fixes (Borislav Petkov)

   - Add missing return statement to a stub function in the ACPI
     processor driver to fix a build issue introduced by recent
     RCU-lockdep fixes (Rafael Wysocki)

   - Fix recently introduced suspicious RCU usage warnings in the PSCI
     cpuidle driver and drop stale comments regarding RCU_NONIDLE()
     usage from enter_s2idle_proper() (Ulf Hansson)

   - Fix error code path in the tegra30 devfreq driver (Dan Carpenter)

   - Add missing information to devfreq_summary debugfs (Chanwoo Choi)"

* tag 'pm-5.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: processor: Fix build for ARCH_APICTIMER_STOPS_ON_C3 unset
  PM / devfreq: tegra30: Disable clock on error in probe
  PM / devfreq: Add timer type to devfreq_summary debugfs
  cpuidle: Drop misleading comments about RCU usage
  cpuidle: psci: Fix suspicious RCU usage
  rcu/tree: Export rcu_idle_{enter,exit} to modules

Pull networking fixes from Jakub Kicinski:

 - fix failure to add bond interfaces to a bridge, the offload-handling
   code was too defensive there and recent refactoring unearthed that.
   Users complained (Ido)

 - fix unnecessarily reflecting ECN bits within TOS values / QoS marking
   in TCP ACK and reset packets (Wei)

 - fix a deadlock with bpf iterator. Hopefully we're in the clear on
   this front now... (Yonghong)

 - BPF fix for clobbering r2 in bpf_gen_ld_abs (Daniel)

 - fix AQL on mt76 devices with FW rate control and add a couple of AQL
   issues in mac80211 code (Felix)

 - fix authentication issue with mwifiex (Maximilian)

 - WiFi connectivity fix: revert IGTK support in ti/wlcore (Mauro)

 - fix exception handling for multipath routes via same device (David
   Ahern)

 - revert back to a BH spin lock flavor for nsid_lock: there are paths
   which do require the BH context protection (Taehee)

 - fix interrupt / queue / NAPI handling in the lantiq driver (Hauke)

 - fix ife module load deadlock (Cong)

 - make an adjustment to netlink reply message type for code added in
   this release (the sole change touching uAPI here) (Michal)

 - a number of fixes for small NXP and Microchip switches (Vladimir)

[ Pull request acked by David: "you can expect more of this in the
  future as I try to delegate more things to Jakub" ]

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (167 commits)
  net: mscc: ocelot: fix some key offsets for IP4_TCP_UDP VCAP IS2 entries
  net: dsa: seville: fix some key offsets for IP4_TCP_UDP VCAP IS2 entries
  net: dsa: felix: fix some key offsets for IP4_TCP_UDP VCAP IS2 entries
  inet_diag: validate INET_DIAG_REQ_PROTOCOL attribute
  net: bridge: br_vlan_get_pvid_rcu() should dereference the VLAN group under RCU
  net: Update MAINTAINERS for MediaTek switch driver
  net/mlx5e: mlx5e_fec_in_caps() returns a boolean
  net/mlx5e: kTLS, Avoid kzalloc(GFP_KERNEL) under spinlock
  net/mlx5e: kTLS, Fix leak on resync error flow
  net/mlx5e: kTLS, Add missing dma_unmap in RX resync
  net/mlx5e: kTLS, Fix napi sync and possible use-after-free
  net/mlx5e: TLS, Do not expose FPGA TLS counter if not supported
  net/mlx5e: Fix using wrong stats_grps in mlx5e_update_ndo_stats()
  net/mlx5e: Fix multicast counter not up-to-date in "ip -s"
  net/mlx5e: Fix endianness when calculating pedit mask first bit
  net/mlx5e: Enable adding peer miss rules only if merged eswitch is supported
  net/mlx5e: CT: Fix freeing ct_label mapping
  net/mlx5e: Fix memory leak of tunnel info when rule under multipath not ready
  net/mlx5e: Use synchronize_rcu to sync with NAPI
  net/mlx5e: Use RCU to protect rq->xdp_prog
  ...

Pull tracing fixes from Steven Rostedt:

 - Check kprobe is enabled before unregistering from ftrace as it isn't
   registered when disabled.

 - Remove kprobes enabled via command-line that is on init text when
   freed.

 - Add missing RCU synchronization for ftrace trampoline symbols removed
   from kallsyms.

 - Free trampoline on error path if ftrace_startup() fails.

 - Give more space for the longer PID numbers in trace output.

 - Fix a possible double free in the histogram code.

 - A couple of fixes that were discovered by sparse.

* tag 'trace-v5.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  bootconfig: init: make xbc_namebuf static
  kprobes: tracing/kprobes: Fix to kill kprobes on initmem after boot
  tracing: fix double free
  ftrace: Let ftrace_enable_sysctl take a kernel pointer buffer
  tracing: Make the space reserved for the pid wider
  ftrace: Fix missing synchronize_rcu() removing trampoline from kallsyms
  ftrace: Free the trampoline when ftrace_startup() fails
  kprobes: Fix to check probe enabled before disarm_kprobe_ftrace()

Pull RCU fix from Paul McKenney:
 "This contains a single commit that fixes a bug that was introduced in
  the last merge window. This bug causes a compiler warning complaining
  about show_rcu_tasks_classic_gp_kthread() being an unused static
  function in !SMP kernels.

  The fix is straightforward, just adding an 'inline' to make this a
  static inline function, thus avoiding the warning.

  This bug was reported by Laurent Pinchart, who would like it fixed
  sooner rather than later"

* 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  rcu-tasks: Prevent complaints of unused show_rcu_tasks_classic_gp_kthread()

Fix this link error:

  ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined!
  ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined!

when CONFIG_ACPI_PROCESSOR is built as module. PeterZ says that in light
of ARM needing those soon too, they should simply be exported.

Fixes: 1fecfdbb7acc ("ACPI: processor: Take over RCU-idle for C3-BM idle")
Reported-by: Sven Joachim <svenjoac@gmx.de>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Paul E. McKenney <paulmckrcu@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull syscall tracing fix from Borislav Petkov:
 "Fix the seccomp syscall rewriting so that trace and audit see the
  rewritten syscall number, from Kees Cook"

* tag 'core_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  core/entry: Report syscall correctly for trace and audit

Pull locking fixes from Borislav Petkov:
 "Two fixes from the locking/urgent pile:

   - Fix lockdep's detection of "USED" <- "IN-NMI" inversions (Peter
     Zijlstra)

   - Make percpu-rwsem operations on the semaphore's ->read_count
     IRQ-safe because it can be used in an IRQ context (Hou Tao)"

* tag 'locking_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/percpu-rwsem: Use this_cpu_{inc,dec}() for read_count
  locking/lockdep: Fix "USED" <- "IN-NMI" inversions

Merge fixes from Andrew Morton:
 "15 patches.

  Subsystems affected by this patch series: mailmap, mm/hotfixes,
  mm/thp, mm/memory-hotplug, misc, kcsan"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  kcsan: kconfig: move to menu 'Generic Kernel Debugging Instruments'
  fs/fs-writeback.c: adjust dirtytime_interval_handler definition to match prototype
  stackleak: let stack_erasing_sysctl take a kernel pointer buffer
  ftrace: let ftrace_enable_sysctl take a kernel pointer buffer
  mm/memory_hotplug: drain per-cpu pages again during memory offline
  selftests/vm: fix display of page size in map_hugetlb
  mm/thp: fix __split_huge_pmd_locked() for migration PMD
  kprobes: fix kill kprobe which has been marked as gone
  tmpfs: restore functionality of nr_inodes=0
  mlock: fix unevictable_pgs event counts on THP
  mm: fix check_move_unevictable_pages() on THP
  mm: migration of hugetlbfs page skip memcg
  ksm: reinstate memcg charge on copied pages
  mailmap: add older email addresses for Kees Cook