The current log space allocation logic is hard to understand or extend.
The principle it that when the log is flushed, we may or may not have a
transaction active that has space allocated in the log.  To deal with
that, we set aside a magical number of blocks to be used in case we
don't have an active transaction.  It isn't clear that the pool will
always be big enough.  In addition, we can't return unused log space at
the end of a transaction, so the number of blocks allocated must exactly
match the number of blocks used.

Simplify this as follows:
 * When transactions are allocated or merged, always reserve enough
   blocks to flush the transaction (err on the safe side).
 * In gfs2_log_flush, return any allocated blocks that haven't been used.
 * Maintain a pool of spare blocks big enough to do one log flush, as
   before.
 * In gfs2_log_flush, when we have no active transaction, allocate a
   suitable number of blocks.  For that, use the spare pool when
   called from logd, and leave the pool alone otherwise.  This means
   that when the log is almost full, logd will still be able to do one
   more log flush, which will result in more log space becoming
   available.

This will make the log space allocator code easier to work with in
the future.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

No functional change.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Move this function further up in log.c so that we can use it in the next patch.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Keep the current value of the updated log tail in the super block as
sb_log_flush_tail instead of computing it on the fly.  This avoids
unnecessary sd_ail_lock taking and cleans up the code.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Use a tighter bound for the number of blocks required by transactions in
gfs2_trans_begin: in the worst case, we'll have mixed data and metadata,
so we'll need a log desciptor for each type.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Wake up log waiters in gfs2_log_release when log space has actually become
available.  This is a much better place for the wakeup than gfs2_logd.

Check if enough log space is immeditely available before anything else.  If
there isn't, use io_wait_event to wait instead of open-coding it.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Commit 588bff95 added gfs2_write_log_header() and started using it in
clean_journal(), with an additional call to log_flush_wait() at the end of
gfs2_write_log_header() which is unnecessary for clean_journal().  Move
that call out of gfs2_write_log_header() to restore the previous behavior.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Move the read locking of sd_log_flush_lock from gfs2_log_reserve to
gfs2_trans_begin, and its unlocking from gfs2_log_release to
gfs2_trans_end.  Use gfs2_log_release in two places in which it was open
coded before.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

This counter and the associated wait queue are only used so that
gfs2_make_fs_ro can efficiently wait for all pending log space
allocations to fail after setting the filesystem to read-only.  This
comes at the cost of waking up that wait queue very frequently.

Instead, when gfs2_log_reserve fails because the filesystem has become
read-only, Wake up sd_log_waitq.  In gfs2_make_fs_ro, set the file
system read-only and then wait until all the log space has been
released.  Give up and report the problem after a while.  With that,
sd_reserving_log and sd_reserving_log_wait can be removed.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Replace the TR_ALLOCED flag by its inverse, TR_ONSTACK: that way, the flag only
needs to be set in the exceptional case of on-stack transactions.  Split off
__gfs2_trans_begin from gfs2_trans_begin and use it to replace the open-coded
version in gfs2_ail_empty_gl.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Commit 2e60d768 ("GFS2: update freeze code to use freeze/thaw_super
on all nodes") optimized away the sb_start_intwrite ... sb_end_intwrite
protection for the on-stack transactions in gfs2_ail_empty_gl with no
explanation.  I can't think of a valid reason for doing that, so revert
that change.  This simplifies the next commit.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Clean up the logic in ail2_empty (no functional change).
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Function gfs2_write_revokes doesn't actually write any revokes; instead, it
adds revokes to the system transaction during a flush.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Split the assert in gfs2_trans_end into two parts.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

The calc_reserved description claims that buf_limit is 502 (on 4k
filesystems), but it is actually 503.  Fix / clarify the entire
description.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Clean up the computations in gfs2_write_revokes (no change in functionality).
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

The BUF_OFFSET and DATABUF_OFFSET definitions are only used in buf_limit
and databuf_limit, respectively, and the rounding done in those
definitions is immediately wiped out by dividing by the element size.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Clean up this function to show that it is trivial.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Pull perf tools fixes from Arnaldo Carvalho de Melo:

 - Fix 'CPU too large' error in Intel PT

 - Correct event attribute sizes in 'perf inject'

 - Sync build_bug.h and kvm.h kernel copies

 - Fix bpf.h header include directive in 5sec.c 'perf trace' bpf example

 - libbpf tests fixes

 - Fix shadow stat 'perf test' for non-bash shells

 - Take cgroups into account for shadow stats in 'perf stat'

* tag 'perf-tools-fixes-2021-01-17' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
  perf inject: Correct event attribute sizes
  perf intel-pt: Fix 'CPU too large' error
  perf stat: Take cgroups into account for shadow stats
  perf stat: Introduce struct runtime_stat_data
  libperf tests: Fail when failing to get a tracepoint id
  libperf tests: If a test fails return non-zero
  libperf tests: Avoid uninitialized variable warning
  perf test: Fix shadow stat test for non-bash shells
  tools headers: Syncronize linux/build_bug.h with the kernel sources
  tools headers UAPI: Sync kvm.h headers with the kernel sources
  perf bpf examples: Fix bpf.h header include directive in 5sec.c example

Pull powerpc fixes from Michael Ellerman:
 "One fix for a lack of alignment in our linker script, that can lead to
  crashes depending on configuration etc.

  One fix for the 32-bit VDSO after the C VDSO conversion.

  Thanks to Andreas Schwab, Ariel Marcovitch, and Christophe Leroy"

* tag 'powerpc-5.11-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/vdso: Fix clock_gettime_fallback for vdso32
  powerpc: Fix alignment bug within the init sections

Pull misc vfs fixes from Al Viro:
 "Several assorted fixes.

  I still think that audit ->d_name race is better fixed this way for
  the benefit of backports, with any possibly fancier variants done on
  top of it"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  dump_common_audit_data(): fix racy accesses to ->d_name
  iov_iter: fix the uaccess area in copy_compat_iovec_from_user
  umount(2): move the flag validity checks first

So technically there is nothing wrong with adding a pinned page to the
swap cache, but the pinning obviously means that the page can't actually
be free'd right now anyway, so it's a bit pointless.

However, the real problem is not with it being a bit pointless: the real
issue is that after we've added it to the swap cache, we'll try to unmap
the page.  That will succeed, because the code in mm/rmap.c doesn't know
or care about pinned pages.

Even the unmapping isn't fatal per se, since the page will stay around
in memory due to the pinning, and we do hold the connection to it using
the swap cache.  But when we then touch it next and take a page fault,
the logic in do_swap_page() will map it back into the process as a
possibly read-only page, and we'll then break the page association on
the next COW fault.

Honestly, this issue could have been fixed in any of those other places:
(a) we could refuse to unmap a pinned page (which makes conceptual
sense), or (b) we could make sure to re-map a pinned page writably in
do_swap_page(), or (c) we could just make do_wp_page() not COW the
pinned page (which was what we historically did before that "mm:
do_wp_page() simplification" commit).

But while all of them are equally valid models for breaking this chain,
not putting pinned pages into the swap cache in the first place is the
simplest one by far.

It's also the safest one: the reason why do_wp_page() was changed in the
first place was that getting the "can I re-use this page" wrong is so
fraught with errors.  If you do it wrong, you end up with an incorrectly
shared page.

As a result, using "page_maybe_dma_pinned()" in either do_wp_page() or
do_swap_page() would be a serious bug since it is only a (very good)
heuristic.  Re-using the page requires a hard black-and-white rule with
no room for ambiguity.

In contrast, saying "this page is very likely dma pinned, so let's not
add it to the swap cache and try to unmap it" is an obviously safe thing
to do, and if the heuristic might very rarely be a false positive, no
harm is done.

Fixes: 09854ba9 ("mm: do_wp_page() simplification")
Reported-and-tested-by: Martin Raiber <martin@urbackup.org>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull SCSI fixes from James Bottomley:
 "Nine minor fixes, seven in drivers and two in the core SCSI disk
  driver (sd) which should be harmless involving removing an unused
  variable and quietening a spurious warning"
Signed-off-by: James E.J. Bottomley <jejb@linux.ibm.com>

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: sd: Remove obsolete variable in sd_remove()
  scsi: sd: Suppress spurious errors when WRITE SAME is being disabled
  scsi: scsi_debug: Fix memleak in scsi_debug_init()
  scsi: mpt3sas: Fix spelling mistake in Kconfig "compatiblity" -> "compatibility"
  scsi: qedi: Correct max length of CHAP secret
  scsi: ufs: Correct the LUN used in eh_device_reset_handler() callback
  scsi: ufs: Relocate flush of exceptional event
  scsi: ufs: Relax the condition of UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH_CTRL
  scsi: ufs: Fix possible power drain during system suspend

We are not guaranteed the locking environment that would prevent
dentry getting renamed right under us.  And it's possible for
old long name to be freed after rename, leading to UAF here.

Cc: stable@kernel.org # v2.6.2+
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Pull block fixes from Jens Axboe:
 "Just an nvme pull request via Christoph:

   - don't initialize hwmon for discover controllers (Sagi Grimberg)

   - fix iov_iter handling in nvme-tcp (Sagi Grimberg)

   - fix a preempt warning in nvme-tcp (Sagi Grimberg)

   - fix a possible NULL pointer dereference in nvme (Israel Rukshin)"

* tag 'block-5.11-2021-01-16' of git://git.kernel.dk/linux-block:
  nvme: don't intialize hwmon for discovery controllers
  nvme-tcp: fix possible data corruption with bio merges
  nvme-tcp: Fix warning with CONFIG_DEBUG_PREEMPT
  nvmet-rdma: Fix NULL deref when setting pi_enable and traddr INADDR_ANY

Pull io_uring fixes from Jens Axboe:
 "We still have a pending fix for a cancelation issue, but it's still
  being investigated. In the meantime:

   - Dead mm handling fix (Pavel)

   - SQPOLL setup error handling (Pavel)

   - Flush timeout sequence fix (Marcelo)

   - Missing finish_wait() for one exit case"

* tag 'io_uring-5.11-2021-01-16' of git://git.kernel.dk/linux-block:
  io_uring: ensure finish_wait() is always called in __io_uring_task_cancel()
  io_uring: flush timeouts that should already have expired
  io_uring: do sqo disable on install_fd error
  io_uring: fix null-deref in io_disable_sqo_submit
  io_uring: don't take files/mm for a dead task
  io_uring: drop mm and files after task_work_run

Pull RISC-V fixes from Palmer Dabbelt:
 "There are a few more fixes than a normal rc4, largely due to the
  bubble introduced by the holiday break:

   - return -ENOSYS for syscall number -1, which previously returned an
     uninitialized value.

   - ensure of_clk_init() has been called in time_init(), without which
     clock drivers may not be initialized.

   - fix sifive,uart0 driver to properly display the baud rate. A fix to
     initialize MPIE that allows interrupts to be processed during
     system calls.

   - avoid erronously begin tracing IRQs when interrupts are disabled,
     which at least triggers suprious lockdep failures.

   - workaround for a warning related to calling smp_processor_id()
     while preemptible. The warning itself is suprious on currently
     availiable systems.

   - properly include the generic time VDSO calls. A fix to our kasan
     address mapping. A fix to the HiFive Unleashed device tree, which
     allows the Ethernet PHY to be properly initialized by Linux (as
     opposed to relying on the bootloader).

   - defconfig update to include SiFive's GPIO driver, which is present
     on the HiFive Unleashed and necessary to initialize the PHY.

   - avoid allocating memory while initializing reserved memory.

   - avoid allocating the last 4K of memory, as pointers there alias
     with syscall errors.

  There are also two cleanups that should have no functional effect but
  do fix build warnings:

   - drop a duplicated definition of PAGE_KERNEL_EXEC.

   - properly declare the asm register SP shim.

   - cleanup the rv32 memory size Kconfig entry, to reflect the actual
     size of memory availiable"

* tag 'riscv-for-linus-5.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  RISC-V: Fix maximum allowed phsyical memory for RV32
  RISC-V: Set current memblock limit
  RISC-V: Do not allocate memblock while iterating reserved memblocks
  riscv: stacktrace: Move register keyword to beginning of declaration
  riscv: defconfig: enable gpio support for HiFive Unleashed
  dts: phy: add GPIO number and active state used for phy reset
  dts: phy: fix missing mdio device and probe failure of vsc8541-01 device
  riscv: Fix KASAN memory mapping.
  riscv: Fixup CONFIG_GENERIC_TIME_VSYSCALL
  riscv: cacheinfo: Fix using smp_processor_id() in preemptible
  riscv: Trace irq on only interrupt is enabled
  riscv: Drop a duplicated PAGE_KERNEL_EXEC
  riscv: Enable interrupts during syscalls with M-Mode
  riscv: Fix sifive serial driver
  riscv: Fix kernel time_init()
  riscv: return -ENOSYS for syscall -1

Turning a pinned page read-only breaks the pinning after COW.  Don't do it.

The whole "track page soft dirty" state doesn't work with pinned pages
anyway, since the page might be dirtied by the pinning entity without
ever being noticed in the page tables.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Turning page table entries read-only requires the mmap_sem held for
writing.

So stop doing the odd games with turning things from read locks to write
locks and back.  Just get the write lock.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Linux kernel can only map 1GB of address space for RV32 as the page offset
is set to 0xC0000000. The current description in the Kconfig is confusing
as it indicates that RV32 can support 2GB of physical memory. That is
simply not true for current kernel. In future, a 2GB split support can be
added to allow 2GB physical address space.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

Currently, linux kernel can not use last 4k bytes of addressable space
because IS_ERR_VALUE macro treats those as an error. This will be an issue
for RV32 as any memblock allocator potentially allocate chunk of memory
from the end of DRAM (2GB) leading bad address error even though the
address was technically valid.

Fix this issue by limiting the memblock if available memory spans the
entire address space.
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

Currently, resource tree allocates memory blocks while iterating on the
list. It leads to following kernel warning because memblock allocation
also invokes memory block reservation API.

[    0.000000] ------------[ cut here ]------------
[    0.000000] WARNING: CPU: 0 PID: 0 at kernel/resource.c:795
__insert_resource+0x8e/0xd0
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted
5.10.0-00022-ge20097fb37e2-dirty #549
[    0.000000] epc: c00125c2 ra : c001262c sp : c1c01f50
[    0.000000]  gp : c1d456e0 tp : c1c0a980 t0 : ffffcf20
[    0.000000]  t1 : 00000000 t2 : 00000000 s0 : c1c01f60
[    0.000000]  s1 : ffffcf00 a0 : ffffff00 a1 : c1c0c0c4
[    0.000000]  a2 : 80c12b15 a3 : 80402000 a4 : 80402000
[    0.000000]  a5 : c1c0c0c4 a6 : 80c12b15 a7 : f5faf600
[    0.000000]  s2 : c1c0c0c4 s3 : c1c0e000 s4 : c1009a80
[    0.000000]  s5 : c1c0c000 s6 : c1d48000 s7 : c1613b4c
[    0.000000]  s8 : 00000fff s9 : 80000200 s10: c1613b40
[    0.000000]  s11: 00000000 t3 : c1d4a000 t4 : ffffffff

This is also unnecessary as we can pre-compute the total memblocks required
for each memory region and allocate it before the loop. It save precious
boot time not going through memblock allocation code every time.

Fixes: 00ab027a ("RISC-V: Add kernel image sections to the resource tree")
Reviewed-by: Anup Patel <anup@brainfault.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

sizeof needs to be called on the compat pointer, not the native one.

Fixes: 89cd35c5 ("iov_iter: transparently handle compat iovecs in import_iovec")
Reported-by: David Laight <David.Laight@ACULAB.COM>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Merge tag 'for-5.11/dm-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:

 - Fix DM-raid's raid1 discard limits so discards work.

 - Select missing Kconfig dependencies for DM integrity and zoned
   targets.

 - Four fixes for DM crypt target's support to optionally bypass kcryptd
   workqueues.

 - Fix DM snapshot merge supports missing data flushes before committing
   metadata.

 - Fix DM integrity data device flushing when external metadata is used.

 - Fix DM integrity's maximum number of supported constructor arguments
   that user can request when creating an integrity device.

 - Eliminate DM core ioctl logging noise when an ioctl is issued without
   required CAP_SYS_RAWIO permission.

* tag 'for-5.11/dm-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm crypt: defer decryption to a tasklet if interrupts disabled
  dm integrity: fix the maximum number of arguments
  dm crypt: do not call bio_endio() from the dm-crypt tasklet
  dm integrity: fix flush with external metadata device
  dm: eliminate potential source of excessive kernel log noise
  dm snapshot: flush merged data before committing metadata
  dm crypt: use GFP_ATOMIC when allocating crypto requests from softirq
  dm crypt: do not wait for backlogged crypto request completion in softirq
  dm zoned: select CONFIG_CRC32
  dm integrity: select CRYPTO_SKCIPHER
  dm raid: fix discard limits for raid1

Merge misc fixes from Andrew Morton:
 "10 patches.

  Subsystems affected by this patch series: MAINTAINERS and mm (slub,
  pagealloc, memcg, kasan, vmalloc, migration, hugetlb, memory-failure,
  and process_vm_access)"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/process_vm_access.c: include compat.h
  mm,hwpoison: fix printing of page flags
  MAINTAINERS: add Vlastimil as slab allocators maintainer
  mm/hugetlb: fix potential missing huge page size info
  mm: migrate: initialize err in do_migrate_pages
  mm/vmalloc.c: fix potential memory leak
  arm/kasan: fix the array size of kasan_early_shadow_pte[]
  mm/memcontrol: fix warning in mem_cgroup_page_lruvec()
  mm/page_alloc: add a missing mm_page_alloc_zone_locked() tracepoint
  mm, slub: consider rest of partial list if acquire_slab() fails

Pull rdma fixes from Jason Gunthorpe:
 "A fairly modest set of bug fixes, nothing abnormal from the merge
  window

  The ucma patch is a bit on the larger side, but given the regression
  was recently added I've opted to forward it to the rc stream.

   - Fix a ucma memory leak introduced in v5.9 while fixing the
     Syzkaller bugs

   - Don't fail when the xarray wraps for user verbs objects

   - User triggerable oops regression from the umem page size rework

   - Error unwind bugs in usnic, ocrdma, mlx5 and cma"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  RDMA/cma: Fix error flow in default_roce_mode_store
  RDMA/mlx5: Fix wrong free of blue flame register on error
  IB/mlx5: Fix error unwinding when set_has_smi_cap fails
  RDMA/umem: Avoid undefined behavior of rounddown_pow_of_two()
  RDMA/ocrdma: Fix use after free in ocrdma_dealloc_ucontext_pd()
  RDMA/usnic: Fix memleak in find_free_vf_and_create_qp_grp
  RDMA/restrack: Don't treat as an error allocation ID wrapping
  RDMA/ucma: Do not miss ctx destruction steps in some cases

If we enter with requests pending and performm cancelations, we'll have
a different inflight count before and after calling prepare_to_wait().
This causes the loop to restart. If we actually ended up canceling
everything, or everything completed in-between, then we'll break out
of the loop without calling finish_wait() on the waitqueue. This can
trigger a warning on exit_signals(), as we leave the task state in
TASK_UNINTERRUPTIBLE.

Put a finish_wait() after the loop to catch that case.

Cc: stable@vger.kernel.org # 5.9+
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull ext4 fixes from Ted Ts'o:
 "A number of bug fixes for ext4:

   - Fix for the new fast_commit feature

   - Fix some error handling codepaths in whiteout handling and
     mountpoint sampling

   - Fix how we write ext4_error information so it goes through the
     journal when journalling is active, to avoid races that can lead to
     lost error information, superblock checksum failures, or DIF/DIX
     features"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: remove expensive flush on fast commit
  ext4: fix bug for rename with RENAME_WHITEOUT
  ext4: fix wrong list_splice in ext4_fc_cleanup
  ext4: use IS_ERR instead of IS_ERR_OR_NULL and set inode null when IS_ERR
  ext4: don't leak old mountpoint samples
  ext4: drop ext4_handle_dirty_super()
  ext4: fix superblock checksum failure when setting password salt
  ext4: use sbi instead of EXT4_SB(sb) in ext4_update_super()
  ext4: save error info to sb through journal if available
  ext4: protect superblock modifications with a buffer lock
  ext4: drop sync argument of ext4_commit_super()
  ext4: combine ext4_handle_error() and save_error_info()

Pull cifs fixes from Steve French:
 "Two small cifs fixes for stable (including an important handle leak
  fix) and three small cleanup patches"

* tag '5.11-rc3-smb3' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: style: replace one-element array with flexible-array
  cifs: connect: style: Simplify bool comparison
  fs: cifs: remove unneeded variable in smb3_fs_context_dup
  cifs: fix interrupted close commands
  cifs: check pointer before freeing