mm: move putting the page on error out of filemap_make_page_uptodate

Move the put_page on error from filemap_make_page_uptodate into the
callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>

mm: move putting the page on error out of filemap_readpage

Move the put_page on error from filemap_readpage into the callers.

Signed-off-by: Christoph Hellwig <hch@lst.de>

mm: refactor generic_file_buffered_read_get_pages

Move the call to filemap_make_page_uptodate for a newly allocated page
into filemap_new_page, which turns the new vs lookup decision into a
plain if / else statement, rename two identifier to be more obvious
and the function itself to filemap_find_or_create_pages which describes
it a little better while being much shorter.

Signed-off-by: Christoph Hellwig <hch@lst.de>

mm: factor out a filemap_find_get_pages helper

Factor out a helper to lookup a range of contiguous pages from
generic_file_buffered_read_get_pages.

Signed-off-by: Christoph Hellwig <hch@lst.de>

mm: simplify generic_file_buffered_read_no_cached_page

Return an errno and add a new by reference argument for the allocated
page, which allows to cleanup the error unwindining in the function
and the caller.  Also rename the function to filemap_new_page which is
both shorter and more descriptive.

Signed-off-by: Christoph Hellwig <hch@lst.de>

mm: handle readahead in generic_file_buffered_read_pagenotuptodate

Move the calculation of the per-page variables and the readahead handling
from the only caller into generic_file_buffered_read_pagenotuptodate,
which now becomes a routine to handle everything related to bringing
one page uptodate and thus is renamed to filemap_read_one_page.

Signed-off-by: Christoph Hellwig <hch@lst.de>

mm: lift the nowait checks into generic_file_buffered_read_pagenotuptodate

Move the checks for IOCB_NOWAIT and IOCB_WAITQ from the only caller into
generic_file_buffered_read_pagenotuptodate, which simplifies the error
unwinding.

Signed-off-by: Christoph Hellwig <hch@lst.de>

mm: simplify generic_file_buffered_read_pagenotuptodate

Stop passing pointless arguments, and return an int instead of a page
struct that contains either the passed in page, an ERR_PTR or NULL and
use goto labels to share common code.

Signed-off-by: Christoph Hellwig <hch@lst.de>

mm: simplify generic_file_buffered_read_readpage

Stop passing pointless arguments, and return an int instead of a page
struct that contains either the passed in page, an ERR_PTR or NULL and
use goto labels to share common code.  Also rename the function to
filemap_readpage as it is a fairly generic wrapper around ->readpage
that isn't really specific to generic_file_buffered_read.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Add linux-next specific files for 20201030

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Merge branch 'akpm/master' into master

mm/gup: assert that the mmap lock is held in __get_user_pages()

After having cleaned up all GUP callers (except for the atomisp staging
driver, which currently gets mmap locking completely wrong [1]) to always
ensure that they hold the mmap lock when calling into GUP (unless the mm
is not yet globally visible), add an assertion to make sure it stays that
way going forward.

[1] https://lore.kernel.org/lkml/CAG48ez3tZAb9JVhw4T5e-i=h2_DUZxfNRTDsagSRCVazNXx5qA@mail.gmail.com/

Link: https://lkml.kernel.org/r/CAG48ez1GM==OnHpS=ghqZNJPn02FCDUEHc7GQmGRMXUD_aKudg@mail.gmail.com
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Michel Lespinasse <walken@google.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

mmap locking API: don't check locking if the mm isn't live yet

In preparation for adding a mmap_assert_locked() check in
__get_user_pages(), teach the mmap_assert_*locked() helpers that it's fine
to operate on an mm without locking in the middle of execve() as long as
it hasn't been installed on a process yet.

Existing code paths that do this are (reverse callgraph):

  get_user_pages_remote
    get_arg_page
      copy_strings
      copy_string_kernel
      remove_arg_zero
    tomoyo_dump_page
      tomoyo_print_bprm
      tomoyo_scan_bprm
      tomoyo_environ

Link: https://lkml.kernel.org/r/CAG48ez03YJG9JU_6tGiMcaVjuTyRE_o4LEQ7901b5ZoCnNAjcg@mail.gmail.com
Signed-off-by: Jann Horn <jannh@google.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

Merge branch 'akpm-current/current' into master

Merge remote-tracking branch 'memblock/for-next' into master

Merge remote-tracking branch 'notifications/notifications-pipe-core' into master

Merge remote-tracking branch 'mhi/mhi-next' into master

Merge remote-tracking branch 'fpga/for-next' into master

Merge remote-tracking branch 'pidfd/for-next' into master

Merge remote-tracking branch 'xarray/main' into master

Merge remote-tracking branch 'nvmem/for-next' into master

Merge remote-tracking branch 'slimbus/for-next' into master

Merge remote-tracking branch 'seccomp/for-next/seccomp' into master

Merge remote-tracking branch 'rtc/rtc-next' into master

Merge remote-tracking branch 'coresight/next' into master

Merge remote-tracking branch 'livepatching/for-next' into master

Merge remote-tracking branch 'kselftest/next' into master

Merge remote-tracking branch 'pinctrl-samsung/for-next' into master

Merge remote-tracking branch 'pinctrl-intel/for-next' into master

Merge remote-tracking branch 'pinctrl/for-next' into master

Merge remote-tracking branch 'gpio-brgl/gpio/for-next' into master

Merge remote-tracking branch 'gpio/for-next' into master

Merge remote-tracking branch 'rpmsg/for-next' into master

Merge remote-tracking branch 'vhost/linux-next' into master

Merge remote-tracking branch 'scsi-mkp/for-next' into master

Merge remote-tracking branch 'dmaengine/next' into master

Merge remote-tracking branch 'icc/icc-next' into master

Merge remote-tracking branch 'mux/for-next' into master

Merge remote-tracking branch 'staging/staging-next' into master

# Conflicts:
# tools/testing/selftests/android/ion/ipcsocket.c
# tools/testing/selftests/android/ion/ipcsocket.h

Merge remote-tracking branch 'extcon/extcon-next' into master

Merge remote-tracking branch 'tty/tty-next' into master

Merge remote-tracking branch 'phy-next/next' into master

# Conflicts:
# MAINTAINERS

Merge remote-tracking branch 'usb-chipidea-next/for-usb-next' into master

Merge remote-tracking branch 'usb-serial/usb-next' into master

Merge remote-tracking branch 'usb/usb-next' into master

Merge remote-tracking branch 'ipmi/for-next' into master

Merge remote-tracking branch 'leds/for-next' into master

Merge remote-tracking branch 'drivers-x86/for-next' into master

Merge remote-tracking branch 'percpu/for-next' into master

Merge remote-tracking branch 'kvm-arm/next' into master

Merge remote-tracking branch 'rcu/rcu/next' into master

# Conflicts:
# include/linux/lockdep.h

Merge remote-tracking branch 'irqchip/irq/irqchip-next' into master

Merge remote-tracking branch 'edac/edac-for-next' into master

Merge remote-tracking branch 'clockevents/timers/drivers/next' into master

Merge remote-tracking branch 'tip/auto-latest' into master

Merge remote-tracking branch 'spi/for-next' into master

Merge remote-tracking branch 'audit/next' into master

Merge remote-tracking branch 'tpmdd/next' into master

Merge remote-tracking branch 'tomoyo/master' into master

Merge remote-tracking branch 'selinux/next' into master

Merge remote-tracking branch 'regulator/for-next' into master

Merge remote-tracking branch 'mmc/next' into master

Merge remote-tracking branch 'block/for-next' into master

Merge remote-tracking branch 'modules/modules-next' into master

Merge remote-tracking branch 'sound-asoc/for-next' into master

Merge remote-tracking branch 'sound/for-next' into master

Merge remote-tracking branch 'regmap/for-next' into master

Merge remote-tracking branch 'etnaviv/etnaviv/next' into master

Merge remote-tracking branch 'imx-drm/imx-drm/next' into master

Merge remote-tracking branch 'mali-dp/for-upstream/mali-dp' into master

next-20201029/drm-misc

Merge remote-tracking branch 'drm-intel/for-linux-next' into master

# Conflicts:
# drivers/gpu/drm/i915/display/intel_ddi.c
# drivers/gpu/drm/i915/display/intel_display.c

Merge remote-tracking branch 'amdgpu/drm-next' into master

# Conflicts:
# drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
# drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
# drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
# drivers/gpu/drm/amd/display/dc/dcn10/dcn10_optc.c
# drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c

Merge remote-tracking branch 'mtd/mtd/next' into master

Merge remote-tracking branch 'gfs2/for-next' into master

Merge remote-tracking branch 'bluetooth/master' into master

Merge remote-tracking branch 'net-next/master' into master

Merge remote-tracking branch 'rdma/for-next' into master

Merge remote-tracking branch 'ieee1394/for-next' into master

Merge remote-tracking branch 'thermal/thermal/linux-next' into master

Merge remote-tracking branch 'opp/opp/linux-next' into master

Merge remote-tracking branch 'devfreq/devfreq-next' into master

Merge remote-tracking branch 'cpupower/cpupower' into master

Merge remote-tracking branch 'cpufreq-arm/cpufreq/arm/linux-next' into master

Merge remote-tracking branch 'pm/linux-next' into master

Merge remote-tracking branch 'v4l-dvb-next/master' into master

Merge remote-tracking branch 'v4l-dvb/master' into master

Merge remote-tracking branch 'jc_docs/docs-next' into master

Merge remote-tracking branch 'hwmon-staging/hwmon-next' into master

Merge remote-tracking branch 'dmi/dmi-for-next' into master

Merge remote-tracking branch 'hid/for-next' into master

Merge remote-tracking branch 'pstore/for-next/pstore' into master

# Conflicts:
# .mailmap

Merge remote-tracking branch 'printk/for-next' into master

Merge remote-tracking branch 'vfs/for-next' into master

Merge remote-tracking branch 'file-locks/locks-next' into master

Merge remote-tracking branch 'xfs/for-next' into master

Merge remote-tracking branch 'f2fs/dev' into master

Merge remote-tracking branch 'ext4/dev' into master

Merge remote-tracking branch 'ext3/for_next' into master

Merge remote-tracking branch 'btrfs/for-next' into master