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71c5576fbd
android_kernel_xiaomi_sdm845/fs
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Andrew Morton 71c5576fbd revert "percpu counter: clean up percpu_counter_sum_and_set()" 
Revert

    commit 1f7c14c62c
    Author: Mingming Cao <cmm@us.ibm.com>
    Date:   Thu Oct 9 12:50:59 2008 -0400

        percpu counter: clean up percpu_counter_sum_and_set()

Before this patch we had the following:

percpu_counter_sum(): return the percpu_counter's value

percpu_counter_sum_and_set(): return the percpu_counter's value, copying
that value into the central value and zeroing the per-cpu counters before
returning.

After this patch, percpu_counter_sum_and_set() has gone, and
percpu_counter_sum() gets the old percpu_counter_sum_and_set()
functionality.

Problem is, as Eric points out, the old percpu_counter_sum_and_set()
functionality was racy and wrong.  It zeroes out counters on "other" cpus,
without holding any locks which will prevent races agaist updates from
those other CPUS.

This patch reverts 1f7c14c62c.  This means
that percpu_counter_sum_and_set() still has the race, but
percpu_counter_sum() does not.

Note that this is not a simple revert - ext4 has since started using
percpu_counter_sum() for its dirty_blocks counter as well.

Note that this revert patch changes percpu_counter_sum() semantics.

Before the patch, a call to percpu_counter_sum() will bring the counter's
central counter mostly up-to-date, so a following percpu_counter_read()
will return a close value.

After this patch, a call to percpu_counter_sum() will leave the counter's
central accumulator unaltered, so a subsequent call to
percpu_counter_read() can now return a significantly inaccurate result.

If there is any code in the tree which was introduced after
e8ced39d5e was merged, and which depends
upon the new percpu_counter_sum() semantics, that code will break.

Reported-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-10 08:01:52 -08:00
..
9p 9p: fix format warning 2008-10-22 18:48:45 -05:00
adfs vfs: Use const for kernel parser table 2008-10-13 10:10:37 -07:00
affs vfs: Use const for kernel parser table 2008-10-13 10:10:37 -07:00
afs [PATCH] fix ->llseek for more directories 2008-10-23 05:13:21 -04:00
autofs vfs: Use const for kernel parser table 2008-10-13 10:10:37 -07:00
autofs4 autofs4: collect version check return 2008-11-06 15:41:17 -08:00
befs befs: annotate fs32 on tests for superblock endianness 2008-10-16 11:21:46 -07:00
bfs [PATCH] fix ->llseek for more directories 2008-10-23 05:13:21 -04:00
cifs [CIFS] fix regression in cifs_write_begin/cifs_write_end 2008-11-26 19:32:33 +00:00
coda Switch to a valid email address... 2008-10-27 08:40:17 -07:00
configfs [PATCH] assorted path_lookup() -> kern_path() conversions 2008-10-23 05:12:52 -04:00
cramfs cramfs: fix named-pipe handling 2008-08-20 15:40:32 -07:00
debugfs integrity: special fs magic 2008-10-13 09:47:43 +11:00
devpts vfs: Use const for kernel parser table 2008-10-13 10:10:37 -07:00
dlm dlm: fix shutdown cleanup 2008-11-13 13:22:34 -06:00
ecryptfs eCryptfs: Allocate up to two scatterlists for crypto ops on keys 2008-11-19 18:49:58 -08:00
efs [PATCH] switch all filesystems over to d_obtain_alias 2008-10-23 05:13:01 -04:00
exportfs EXPORTFS: handle NULL returns from fh_to_dentry()/fh_to_parent() 2008-12-08 19:49:32 -08:00
ext2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/viro/bdev 2008-10-23 10:23:07 -07:00
ext3 ext3: Clean up outdated and incorrect comment for ext3_write_super() 2008-11-12 17:17:17 -08:00
ext4 revert "percpu counter: clean up percpu_counter_sum_and_set()" 2008-12-10 08:01:52 -08:00
fat fat: i_blocks warning fix 2008-11-06 15:41:22 -08:00
freevxfs
fuse saner FASYNC handling on file close 2008-11-01 09:49:46 -07:00
gfs2 [PATCH] switch all filesystems over to d_obtain_alias 2008-10-23 05:13:01 -04:00
hfs [PATCH] move executable checking into ->permission() 2008-10-23 05:13:25 -04:00
hfsplus [PATCH] move executable checking into ->permission() 2008-10-23 05:13:25 -04:00
hostfs hostfs: fix a duplicated global function name 2008-11-19 18:50:00 -08:00
hpfs [PATCH] hpfs: cleanup ->setattr 2008-10-23 05:12:58 -04:00
hppfs [patch] hppfs: remove hppfs_permission 2008-07-26 20:53:07 -04:00
hugetlbfs vfs: Use const for kernel parser table 2008-10-13 10:10:37 -07:00
isofs [PATCH] switch all filesystems over to d_obtain_alias 2008-10-23 05:13:01 -04:00
jbd jbd: don't give up looking for space so easily in __log_wait_for_space 2008-11-06 22:37:59 -05:00
jbd2 jbd2: don't give up looking for space so easily in __jbd2_log_wait_for_space 2008-11-06 22:38:07 -05:00
jffs2 Merge git://git.infradead.org/mtd-2.6 2008-11-06 15:43:13 -08:00
jfs Merge git://git.kernel.org/pub/scm/linux/kernel/git/viro/bdev 2008-10-23 10:23:07 -07:00
lockd NLM: client-side nlm_lookup_host() should avoid matching on srcaddr 2008-11-24 13:29:07 -06:00
minix SL*B: drop kmem cache argument from constructor 2008-07-26 12:00:07 -07:00
ncpfs [PATCH] don't pass nameidata to __ncp_lookup_validate() 2008-07-26 20:53:37 -04:00
nfs NFS: Convert nfs_attr_generation_counter into an atomic_long 2008-10-28 15:21:40 -04:00
nfs_common
nfsd nfsd: use of unitialized list head on error exit in nfs4recover.c 2008-11-24 10:36:09 -06:00
nls remove CONFIG_KMOD from fs 2008-10-17 02:38:36 +11:00
ntfs ntfs: don't fool kernel-doc 2008-12-01 19:55:25 -08:00
ocfs2 ocfs2: fix regression in ocfs2_read_blocks_sync() 2008-12-01 14:46:58 -08:00
omfs [PATCH] fix ->llseek for more directories 2008-10-23 05:13:21 -04:00
openpromfs [PATCH] fix ->llseek for more directories 2008-10-23 05:13:21 -04:00
partitions block/md: fix md autodetection 2008-11-18 15:08:56 +01:00
proc Fix broken ownership of /proc/sys/ files 2008-11-16 15:09:52 -08:00
qnx4 SL*B: drop kmem cache argument from constructor 2008-07-26 12:00:07 -07:00
ramfs Ramfs and Ram Disk pages are unevictable 2008-10-20 08:50:26 -07:00
reiserfs Merge git://git.kernel.org/pub/scm/linux/kernel/git/viro/bdev 2008-10-23 10:23:07 -07:00
romfs romfs_readpage: don't report errors for pages beyond i_size 2008-07-30 14:30:34 -07:00
smbfs [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
sysfs [PATCH] fix ->llseek for more directories 2008-10-23 05:13:21 -04:00
sysv SL*B: drop kmem cache argument from constructor 2008-07-26 12:00:07 -07:00
ubifs UBIFS: pre-allocate bulk-read buffer 2008-11-21 18:59:33 +02:00
udf udf: Fix BUG_ON() in destroy_inode() 2008-11-27 17:38:28 +01:00
ufs [PATCH] fix ->llseek for more directories 2008-10-23 05:13:21 -04:00
xfs [XFS] Fix hang after disallowed rename across directory quota domains 2008-12-05 15:39:13 +11:00
aio.c [PATCH] f_count may wrap around 2008-07-26 20:53:40 -04:00
anon_inodes.c flag parameters: NONBLOCK in anon_inode_getfd 2008-07-24 10:47:28 -07:00
attr.c [patch] vfs: make security_inode_setattr() calling consistent 2008-10-23 05:13:27 -04:00
bad_inode.c [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
binfmt_aout.c tracehook: exec 2008-07-26 12:00:08 -07:00
binfmt_elf_fdpic.c binfmt_elf_fdpic: Update for cputime changes. 2008-10-20 20:17:18 -07:00
binfmt_elf.c Merge branch 'v28-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-10-20 13:19:56 -07:00
binfmt_em86.c Allow recursion in binfmt_script and binfmt_misc 2008-10-16 11:21:38 -07:00
binfmt_flat.c uclinux: fix gzip header parsing in binfmt_flat.c 2008-10-16 11:21:29 -07:00
binfmt_misc.c Allow recursion in binfmt_script and binfmt_misc 2008-10-16 11:21:38 -07:00
binfmt_script.c Allow recursion in binfmt_script and binfmt_misc 2008-10-16 11:21:38 -07:00
binfmt_som.c binfmt_som.c: add MODULE_LICENSE 2008-10-16 11:21:38 -07:00
bio-integrity.c block: Introduce integrity data ownership flag 2008-10-09 08:56:21 +02:00
bio.c block: mark bio_split_pool static 2008-10-09 08:57:05 +02:00
block_dev.c [PATCH 1/2] kill FMODE_NDELAY_NOW 2008-12-04 04:22:57 -05:00
buffer.c udf: Fix BUG_ON() in destroy_inode() 2008-11-27 17:38:28 +01:00
char_dev.c [PATCH] tidy up chrdev_open 2008-10-23 05:12:59 -04:00
compat_binfmt_elf.c
compat_ioctl.c remove unused #include <linux/dirent.h>'s 2008-07-25 10:53:34 -07:00
compat.c select: deal with math overflow from borderline valid userland data 2008-10-26 11:22:08 -07:00
dcache.c [PATCH] fs: add a sanity check in d_free 2008-10-23 05:17:12 -04:00
dcookies.c
direct-io.c Remove Andrew Morton's old email accounts 2008-10-16 11:21:32 -07:00
dnotify.c
dquot.c [PATCH] switch quota_on-related stuff to kern_path() 2008-10-23 05:12:44 -04:00
drop_caches.c
eventfd.c flag parameters: check magic constants 2008-07-24 10:47:29 -07:00
eventpoll.c epoll: introduce resource usage limits 2008-12-01 19:55:24 -08:00
exec.c coredump: format_corename: don't append .%pid if multi-threaded 2008-10-20 08:52:39 -07:00
fcntl.c Fix a race condition in FASYNC handling 2008-12-05 15:35:10 -08:00
fifo.c [PATCH] introduce fmode_t, do annotations 2008-10-21 07:47:06 -04:00
file_table.c saner FASYNC handling on file close 2008-11-01 09:49:46 -07:00
file.c [PATCH] merge locate_fd() and get_unused_fd() 2008-08-01 11:25:23 -04:00
filesystems.c proc: move /proc/filesystems to fs/filesystems.c 2008-10-23 14:27:09 +04:00
fs-writeback.c Remove Andrew Morton's old email accounts 2008-10-16 11:21:32 -07:00
generic_acl.c
inode.c fs/inode.c: properly init address_space->writeback_index 2008-08-15 08:35:44 -07:00
inotify_user.c saner FASYNC handling on file close 2008-11-01 09:49:46 -07:00
inotify.c Fix inotify watch removal/umount races 2008-11-15 12:26:44 -08:00
internal.h
ioctl.c Fix a race condition in FASYNC handling 2008-12-05 15:35:10 -08:00
ioprio.c fix setpriority(PRIO_PGRP) thread iterator breakage 2008-08-20 15:40:32 -07:00
Kconfig [patch 1/3] FS_MBCACHE: don't needlessly make it built-in 2008-10-23 05:13:26 -04:00
Kconfig.binfmt add CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS 2008-10-20 08:52:39 -07:00
libfs.c fs: remove prepare_write/commit_write 2008-10-30 11:38:45 -07:00
locks.c Merge branch 'proc' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc 2008-10-23 12:04:37 -07:00
Makefile fat: move fs/vfat/* and fs/msdos/* to fs/fat 2008-11-06 15:41:20 -08:00
mbcache.c
mpage.c Remove Andrew Morton's old email accounts 2008-10-16 11:21:32 -07:00
namei.c don't unlink an active swapfile 2008-11-19 18:49:59 -08:00
namespace.c vfs: fix shrink_submounts 2008-11-12 17:17:17 -08:00
nfsctl.c
no-block.c
open.c [PATCH] introduce fmode_t, do annotations 2008-10-21 07:47:06 -04:00
pipe.c saner FASYNC handling on file close 2008-11-01 09:49:46 -07:00
pnode.c
pnode.h
posix_acl.c
quota_v1.c quota: move function-macros from quota.h to quotaops.h 2008-07-25 10:53:35 -07:00
quota_v2.c quota: move function-macros from quota.h to quotaops.h 2008-07-25 10:53:35 -07:00
quota.c quota: cleanup loop in sync_dquots() 2008-07-25 10:53:35 -07:00
read_write.c [PATCH] generic_file_llseek tidyups 2008-10-23 05:12:59 -04:00
read_write.h
readdir.c [PATCH] prepare vfs_readdir() callers to returning filldir result 2008-10-23 05:13:10 -04:00
select.c select: deal with math overflow from borderline valid userland data 2008-10-26 11:22:08 -07:00
seq_file.c seq_file: add seq_cpumask_list(), seq_nodemask_list() 2008-10-20 08:52:39 -07:00
signalfd.c flag parameters: check magic constants 2008-07-24 10:47:29 -07:00
splice.c fs: remove prepare_write/commit_write 2008-10-30 11:38:45 -07:00
stack.c
stat.c [PATCH] sanitize __user_walk_fd() et.al. 2008-07-26 20:53:34 -04:00
super.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/viro/bdev 2008-10-23 10:23:07 -07:00
sync.c SYNC_FILE_RANGE_WRITE may and will block. Document that. 2008-07-24 10:47:17 -07:00
timerfd.c hrtimer: convert timerfd to the new hrtimer apis 2008-09-05 21:35:09 -07:00
utimes.c [PATCH] sanitize __user_walk_fd() et.al. 2008-07-26 20:53:34 -04:00
xattr_acl.c
xattr.c [PATCH] sanitize __user_walk_fd() et.al. 2008-07-26 20:53:34 -04:00