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Linus Torvalds f9bf352224 userfaultfd: simplify fault handling
Instead of waiting in a loop for the userfaultfd condition to become
true, just wait once and return VM_FAULT_RETRY.

We've already dropped the mmap lock, we know we can't really
successfully handle the fault at this point and the caller will have to
retry anyway.  So there's no point in making the wait any more
complicated than it needs to be - just schedule away.

And once you don't have that complexity with explicit looping, you can
also just lose all the 'userfaultfd_signal_pending()' complexity,
because once we've set the correct process sleeping state, and don't
loop, the act of scheduling itself will be checking if there are any
pending signals before going to sleep.

We can also drop the VM_FAULT_MAJOR games, since we'll be treating all
retried faults as major soon anyway (series to regularize and share more
of fault handling across architectures in a separate series by Peter Xu,
and in the meantime we won't worry about the possible minor - I'll be
here all week, try the veal - accounting difference).

Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-03 11:25:16 -07:00
arch Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-03 10:40:14 -07:00
block block-5.8-2020-07-10 2020-07-10 09:55:46 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-03 10:40:14 -07:00
Documentation Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-03 10:40:14 -07:00
drivers Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-03 10:40:14 -07:00
fs userfaultfd: simplify fault handling 2020-08-03 11:25:16 -07:00
include Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-03 10:40:14 -07:00
init kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang 2020-07-02 00:57:45 +09:00
ipc mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
kernel Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-03 10:40:14 -07:00
lib Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-03 10:40:14 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm list: add "list_del_init_careful()" to go with "list_empty_careful()" 2020-08-02 20:39:44 -07:00
net Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-03 10:40:14 -07:00
samples samples/vfs: avoid warning in statx override 2020-07-03 16:15:25 -07:00
scripts kbuild: remove redundant FORCE definition in scripts/Makefile.modpost 2020-08-02 23:09:16 +09:00
security integrity/ima: switch to using __kernel_read 2020-07-08 08:27:57 +02:00
sound Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-03 10:40:14 -07:00
tools Bugfixes and strengthening the validity checks on inputs from new userspace APIs. 2020-08-02 10:41:00 -07:00
usr bpfilter: match bit size of bpfilter_umh to that of the kernel 2020-05-17 18:52:01 +09:00
virt kvm: use more precise cast and do not drop __user 2020-07-02 05:39:31 -04:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Do not track defconfig from make savedefconfig 2020-07-05 16:15:46 +09:00
.mailmap mailmap: add entry for Mike Rapoport 2020-07-24 12:42:41 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS mailmap: change email for Ricardo Ribalda 2020-05-25 18:59:59 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-03 10:40:14 -07:00
Makefile Linux 5.8 2020-08-02 14:21:45 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.