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Andreas Gruenbacher 640a6be8e8 gfs2: Fix mmap + page fault deadlocks for direct I/O
commit b01b2d72da upstream

Also disable page faults during direct I/O requests and implement a
similar kind of retry logic as in the buffered I/O case.

The retry logic in the direct I/O case differs from the buffered I/O
case in the following way: direct I/O doesn't provide the kinds of
consistency guarantees between concurrent reads and writes that buffered
I/O provides, so once we lose the inode glock while faulting in user
pages, we always resume the operation.  We never need to return a
partial read or write.

This locking problem was originally reported by Jan Kara.  Linus came up
with the idea of disabling page faults.  Many thanks to Al Viro and
Matthew Wilcox for their feedback.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-05-01 17:22:33 +02:00
arch gup: Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable} 2022-05-01 17:22:28 +02:00
block block/compat_ioctl: fix range check in BLKGETSIZE 2022-04-27 14:39:02 +02:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto crypto: xts - Add softdep on ecb 2022-04-08 14:23:55 +02:00
Documentation ext4, doc: fix incorrect h_reserved size 2022-04-27 14:39:01 +02:00
drivers gup: Turn fault_in_pages_{readable,writeable} into fault_in_{readable,writeable} 2022-05-01 17:22:28 +02:00
fs gfs2: Fix mmap + page fault deadlocks for direct I/O 2022-05-01 17:22:33 +02:00
include iov_iter: Introduce nofault flag to disable page faults 2022-05-01 17:22:33 +02:00
init init/main.c: return 1 from handled __setup() functions 2022-04-13 20:59:10 +02:00
ipc ipc/sem: do not sleep with a spin lock held 2022-02-08 18:34:03 +01:00
kernel bpf: Fix crash due to out of bounds access into reg2btf_ids. 2022-05-01 17:22:26 +02:00
lib iov_iter: Introduce nofault flag to disable page faults 2022-05-01 17:22:33 +02:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm gup: Introduce FOLL_NOFAULT flag to disable page faults 2022-05-01 17:22:32 +02:00
net bpf: Add MEM_RDONLY for helper args that are pointers to rdonly mem. 2022-05-01 17:22:26 +02:00
samples samples/bpf, xdpsock: Fix race when running for fix duration of time 2022-04-08 14:23:40 +02:00
scripts gcc-plugins: latent_entropy: use /dev/urandom 2022-04-20 09:34:18 +02:00
security Fix incorrect type in assignment of ipv6 port for audit 2022-04-08 14:23:55 +02:00
sound ASoC: soc-dapm: fix two incorrect uses of list iterator 2022-04-27 14:39:00 +02:00
tools bpf/selftests: Test PTR_TO_RDONLY_MEM 2022-05-01 17:22:26 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: avoid NULL pointer dereference in kvm_dirty_ring_push 2022-04-13 20:59:26 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +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: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
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 MAINTAINERS: adjust file entry for of_net.c after movement 2022-03-08 19:12:53 +01:00
Makefile Linux 5.15.36 2022-04-27 14:39:02 +02:00
README

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.