The documentation and the code disagrees; fix the former.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The IRQF_DISABLED is a NOOP and scheduled to be removed. According to Ingo
Molnar in commit e58aa3d2d0 (genirq: Run irq
handlers with interrupts disabled), running IRQ handlers with interrupts
enabled can cause stack overflows when the interrupt line of the issuing
device is still active.
This patch removes IRQF_DISABLED from this documentation. It was
mentioned to be a solution to avoid deadlocks when a device uses
multiple interrupts. As the flag is a NOOP this solution does not work
anymore.
Signed-off-by: Valentin Rothberg <Valentin.Rothberg@lip6.fr>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
max_ptes_none specifies how many extra small pages (that are
not already mapped) can be allocated when collapsing a group
of small pages into one large page.
/sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none
A higher value leads to use additional memory for programs.
A lower value leads to gain less thp performance. Value of
max_ptes_none can waste cpu time very little, you can
ignore it.
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
as the commit: "lib/vsprintf: implement bitmap printing through
'%*pb[l]'" add an easy way to print bitmaps. so printk-formats.txt
should reflect it.
Signed-off-by: Wang Long <long.wanglong@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Documentation/memory-hotplug.txt describes that a callback function can
be added to the notification chain by calling hotplug_memory_notifier().
The function prototype of the callback function is mssing. This missing
information is added by the patch.
The description of the arguments of the callback function is
reworked.
The constants for the event types are corrected.
The possible return values are explained.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Try to make coding style documentation look a bit more readable and
consistent with the following:
- indent every code example in C to first tab-stop;
- surround every code example with empty lines, both top and bottom;
- remove empty lines where text looked way too spare;
- do not indent examples in elisp and kconfig;
- do not do any non-whitespace changes.
Signed-off-by: Pavel Kretov <firegurafiku@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Coding style description has a irregular mixture of tabs and spaces in two
places which is bad by any means and can possibly hurt somebody's sense
of beauty.
Signed-off-by: Pavel Kretov <firegurafiku@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Even "private" structure members need a leading "@" in their
kernel-doc; otherwise, they will be treated as new section names in
the resulting manual.
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Acked-By: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The documentation specified that a machine type is mandatory and made
that assumption in a few places. However, for DT-only platforms, the
current advice is that no machine type should be registered, so update
accordingly.
Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
.. after extensive statistical analysis of my G+ polling, I've come to
the inescapable conclusion that internet polls are bad.
Big surprise.
But "Hurr durr I'ma sheep" trounced "I like online polls" by a 62-to-38%
margin, in a poll that people weren't even supposed to participate in.
Who can argue with solid numbers like that? 5,796 votes from people who
can't even follow the most basic directions?
In contrast, "v4.0" beat out "v3.20" by a slimmer margin of 56-to-44%,
but with a total of 29,110 votes right now.
Now, arguably, that vote spread is only about 3,200 votes, which is less
than the almost six thousand votes that the "please ignore" poll got, so
it could be considered noise.
But hey, I asked, so I'll honor the votes.
Pull ext4 fixes from Ted Ts'o:
"Ext4 bug fixes.
We also reserved code points for encryption and read-only images (for
which the implementation is mostly just the reserved code point for a
read-only feature :-)"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: fix indirect punch hole corruption
ext4: ignore journal checksum on remount; don't fail
ext4: remove duplicate remount check for JOURNAL_CHECKSUM change
ext4: fix mmap data corruption in nodelalloc mode when blocksize < pagesize
ext4: support read-only images
ext4: change to use setup_timer() instead of init_timer()
ext4: reserve codepoints used by the ext4 encryption feature
jbd2: complain about descriptor block checksum errors
Pull more vfs updates from Al Viro:
"Assorted stuff from this cycle. The big ones here are multilayer
overlayfs from Miklos and beginning of sorting ->d_inode accesses out
from David"
* 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (51 commits)
autofs4 copy_dev_ioctl(): keep the value of ->size we'd used for allocation
procfs: fix race between symlink removals and traversals
debugfs: leave freeing a symlink body until inode eviction
Documentation/filesystems/Locking: ->get_sb() is long gone
trylock_super(): replacement for grab_super_passive()
fanotify: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversions
Cachefiles: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversions
VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry)
SELinux: Use d_is_positive() rather than testing dentry->d_inode
Smack: Use d_is_positive() rather than testing dentry->d_inode
TOMOYO: Use d_is_dir() rather than d_inode and S_ISDIR()
Apparmor: Use d_is_positive/negative() rather than testing dentry->d_inode
Apparmor: mediated_filesystem() should use dentry->d_sb not inode->i_sb
VFS: Split DCACHE_FILE_TYPE into regular and special types
VFS: Add a fallthrough flag for marking virtual dentries
VFS: Add a whiteout dentry type
VFS: Introduce inode-getting helpers for layered/unioned fs environments
Infiniband: Fix potential NULL d_inode dereference
posix_acl: fix reference leaks in posix_acl_create
autofs4: Wrong format for printing dentry
...
Pull ARM fix from Russell King:
"Just one fix this time around. __iommu_alloc_buffer() can cause a
BUG() if dma_alloc_coherent() is called with either __GFP_DMA32 or
__GFP_HIGHMEM set. The patch from Alexandre addresses this"
* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
ARM: 8305/1: DMA: Fix kzalloc flags in __iommu_alloc_buffer()
As it is, we have debugfs_remove() racing with symlink traversals.
Supply ->evict_inode() and do freeing there - inode will remain
pinned until we are done with the symlink body.
And rip the idiocy with checking if dentry is positive right after
we'd verified debugfs_positive(), which is a stronger check...
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
I've noticed significant locking contention in memory reclaimer around
sb_lock inside grab_super_passive(). Grab_super_passive() is called from
two places: in icache/dcache shrinkers (function super_cache_scan) and
from writeback (function __writeback_inodes_wb). Both are required for
progress in memory allocator.
Grab_super_passive() acquires sb_lock to increment sb->s_count and check
sb->s_instances. It seems sb->s_umount locked for read is enough here:
super-block deactivation always runs under sb->s_umount locked for write.
Protecting super-block itself isn't a problem: in super_cache_scan() sb
is protected by shrinker_rwsem: it cannot be freed if its slab shrinkers
are still active. Inside writeback super-block comes from inode from bdi
writeback list under wb->list_lock.
This patch removes locking sb_lock and checks s_instances under s_umount:
generic_shutdown_super() unlinks it under sb->s_umount locked for write.
New variant is called trylock_super() and since it only locks semaphore,
callers must call up_read(&sb->s_umount) instead of drop_super(sb) when
they're done.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Fanotify probably doesn't want to watch autodirs so make it use d_can_lookup()
rather than d_is_dir() when checking a dir watch and give an error on fake
directories.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Fix up the following scripted S_ISDIR/S_ISREG/S_ISLNK conversions (or lack
thereof) in cachefiles:
(1) Cachefiles mostly wants to use d_can_lookup() rather than d_is_dir() as
it doesn't want to deal with automounts in its cache.
(2) Coccinelle didn't find S_IS* expressions in ASSERT() statements in
cachefiles.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Convert the following where appropriate:
(1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry).
(2) S_ISREG(dentry->d_inode) to d_is_reg(dentry).
(3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more
complicated than it appears as some calls should be converted to
d_can_lookup() instead. The difference is whether the directory in
question is a real dir with a ->lookup op or whether it's a fake dir with
a ->d_automount op.
In some circumstances, we can subsume checks for dentry->d_inode not being
NULL into this, provided we the code isn't in a filesystem that expects
d_inode to be NULL if the dirent really *is* negative (ie. if we're going to
use d_inode() rather than d_backing_inode() to get the inode pointer).
Note that the dentry type field may be set to something other than
DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS
manages the fall-through from a negative dentry to a lower layer. In such a
case, the dentry type of the negative union dentry is set to the same as the
type of the lower dentry.
However, if you know d_inode is not NULL at the call site, then you can use
the d_is_xxx() functions even in a filesystem.
There is one further complication: a 0,0 chardev dentry may be labelled
DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was
intended for special directory entry types that don't have attached inodes.
The following perl+coccinelle script was used:
use strict;
my @callers;
open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') ||
die "Can't grep for S_ISDIR and co. callers";
@callers = <$fd>;
close($fd);
unless (@callers) {
print "No matches\n";
exit(0);
}
my @cocci = (
'@@',
'expression E;',
'@@',
'',
'- S_ISLNK(E->d_inode->i_mode)',
'+ d_is_symlink(E)',
'',
'@@',
'expression E;',
'@@',
'',
'- S_ISDIR(E->d_inode->i_mode)',
'+ d_is_dir(E)',
'',
'@@',
'expression E;',
'@@',
'',
'- S_ISREG(E->d_inode->i_mode)',
'+ d_is_reg(E)' );
my $coccifile = "tmp.sp.cocci";
open($fd, ">$coccifile") || die $coccifile;
print($fd "$_\n") || die $coccifile foreach (@cocci);
close($fd);
foreach my $file (@callers) {
chomp $file;
print "Processing ", $file, "\n";
system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 ||
die "spatch failed";
}
[AV: overlayfs parts skipped]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use d_is_positive() rather than testing dentry->d_inode in SELinux to get rid
of direct references to d_inode outside of the VFS.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use d_is_positive() rather than testing dentry->d_inode in Smack to get rid of
direct references to d_inode outside of the VFS.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use d_is_dir() rather than d_inode and S_ISDIR(). Note that this will include
fake directories such as automount triggers.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Rasmus Villemoes
Valentin Rothberg
Ebru Akagunduz
Wang Long
Masanari Iida
Heinrich Schuchardt
Pavel Kretov
Robert P. J. Day
Gregory Fong
Linus Torvalds
Al Viro
Konstantin Khlebnikov
David Howells