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Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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The "strictlimit" feature was introduced to enforce per-bdi dirty limits
for FUSE which sets bdi max_ratio to 1% by default:
http://article.gmane.org/gmane.linux.kernel.mm/105809
However the feature can be useful for other relatively slow or untrusted
BDIs like USB flash drives and DVD+RW. The patch adds a knob to enable
the feature:
echo 1 > /sys/class/bdi/X:Y/strictlimit
Being enabled, the feature enforces bdi max_ratio limit even if global
(10%) dirty limit is not reached. Of course, the effect is not visible
until /sys/class/bdi/X:Y/max_ratio is decreased to some reasonable value.
Signed-off-by: Maxim Patlasov <MPatlasov@parallels.com>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: "Artem S. Tashkinov" <t.artem@lycos.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently, memsetting and kfreeing the device is bad behaviour. The
device will have a reference count of 1 and hence can cause trouble
because it has kfree'd. Proper way to handle a failed device_register is
to call put_device right after it fails.
Signed-off-by: Levente Kurusa <levex@linux.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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remap_file_pages(2) was invented to be able efficiently map parts of huge
file into limited 32-bit virtual address space such as in database
workloads.
Nonlinear mappings are pain to support and it seems there's no legitimate
use-cases nowadays since 64-bit systems are widely available.
Let's drop it and get rid of all these special-cased code.
The patch replaces the syscall with emulation which creates new VMA on
each remap_file_pages(), unless they it can be merged with an adjacent
one.
I didn't find *any* real code that uses remap_file_pages(2) to test
emulation impact on. I've checked Debian code search and source of all
packages in ALT Linux. No real users: libc wrappers, mentions in strace,
gdb, valgrind and this kind of stuff.
There are few basic tests in LTP for the syscall. They work just fine
with emulation.
To test performance impact, I've written small test case which demonstrate
pretty much worst case scenario: map 4G shmfs file, write to begin of
every page pgoff of the page, remap pages in reverse order, read every
page.
The test creates 1 million of VMAs if emulation is in use, so I had to set
vm.max_map_count to 1100000 to avoid -ENOMEM.
Before: 23.3 ( +- 4.31% ) seconds
After: 43.9 ( +- 0.85% ) seconds
Slowdown: 1.88x
I believe we can live with that.
Test case:
#define _GNU_SOURCE
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/mman.h>
#define MB (1024UL * 1024)
#define SIZE (4096 * MB)
int main(int argc, char **argv)
{
unsigned long *p;
long i, pass;
for (pass = 0; pass < 10; pass++) {
p = mmap(NULL, SIZE, PROT_READ|PROT_WRITE,
MAP_SHARED | MAP_ANONYMOUS, -1, 0);
if (p == MAP_FAILED) {
perror("mmap");
return -1;
}
for (i = 0; i < SIZE / 4096; i++)
p[i * 4096 / sizeof(*p)] = i;
for (i = 0; i < SIZE / 4096; i++) {
if (remap_file_pages(p + i * 4096 / sizeof(*p), 4096,
0, (SIZE - 4096 * (i + 1)) >> 12, 0)) {
perror("remap_file_pages");
return -1;
}
}
for (i = SIZE / 4096 - 1; i >= 0; i--)
assert(p[i * 4096 / sizeof(*p)] == SIZE / 4096 - i - 1);
munmap(p, SIZE);
}
return 0;
}
[akpm@linux-foundation.org: fix spello]
[sasha.levin@oracle.com: initialize populate before usage]
[sasha.levin@oracle.com: grab file ref to prevent race while mmaping]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Armin Rigo <arigo@tunes.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Update the limitation for fat fallocate.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Make the fibmap call the return the proper physical block number for any
offset request in the fallocated range.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Skip new cluster allocation after checking i_disksize in _fat_get_block.
because the blocks are already allocated in fallocated region.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Implement preallocation via the fallocate syscall on VFAT partitions.
This patch is based on an earlier patch of the same name which had some
issues detailed below and did not get accepted. Refer
https://lkml.org/lkml/2007/12/22/130.
a) The preallocated space was not persistent when the
FALLOC_FL_KEEP_SIZE flag was set. It will deallocate cluster at evict
time.
b) There was no need to zero out the clusters when the flag was set
Instead of doing an expanding truncate, just allocate clusters and add
them to the fat chain. This reduces preallocation time.
Compatibility with windows:
There are no issues when FALLOC_FL_KEEP_SIZE is not set because it just
does an expanding truncate. Thus reading from the preallocated area on
windows returns null until data is written to it.
When a file with preallocated area using the FALLOC_FL_KEEP_SIZE was
written to on windows, the windows driver freed-up the preallocated
clusters and allocated new clusters for the new data. The freed up
clusters gets reflected in the free space available for the partition
which can be seen from the Volume properties.
The windows chkdsk tool also does not report any errors on a disk
containing files with preallocated space.
And there is also no issue using linux fat fsck. because discard
preallocated clusters at repair time.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This patchset provides support for doing fallocate operation on FAT
filesystem.
This patch (of 5):
Add i_disksize to represent uninitialized allocated size. And mmu_private
represent initialized allocated size. i_disksize - is always kept cluster
size aligned mmu_private - is normally block size aligned
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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For completeness of the arch-independent pgprot-modify,
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jamie Liu <jamieliu@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Peter Feiner <pfeiner@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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For VMAs that don't want write notifications, PTEs created for read faults
have their write bit set. If the read fault happens after VM_SOFTDIRTY is
cleared, then the PTE's softdirty bit will remain clear after subsequent
writes.
Here's a simple code snippet to demonstrate the bug:
char* m = mmap(NULL, getpagesize(), PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_SHARED, -1, 0);
system("echo 4 > /proc/$PPID/clear_refs"); /* clear VM_SOFTDIRTY */
assert(*m == '\0'); /* new PTE allows write access */
assert(!soft_dirty(x));
*m = 'x'; /* should dirty the page */
assert(soft_dirty(x)); /* fails */
With this patch, write notifications are enabled when VM_SOFTDIRTY is
cleared. Furthermore, to avoid unnecessary faults, write notifications
are disabled when VM_SOFTDIRTY is set.
As a side effect of enabling and disabling write notifications with care,
this patch fixes a bug in mprotect where vm_page_prot bits set by drivers
were zapped on mprotect. An analogous bug was fixed in mmap by
c9d0bf241451a3ab7d ("mm: uncached vma support with writenotify").
Signed-off-by: Peter Feiner <pfeiner@google.com>
Reported-by: Peter Feiner <pfeiner@google.com>
Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Jamie Liu <jamieliu@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Consolidate the various external const and non-const declarations of
__start___param[] and __stop___param in <linux/moduleparam.h>. This
requires making a few struct kernel_param pointers in kernel/params.c
const.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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They're already provided by <asm/sections.h>.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Use watchdog_enable_hardlockup_detector() to set hard lockup detection's
default value to false. It's risky to run this detection in a guest, as
false positives are easy to trigger, especially if the host is
overcommitted.
Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Sparc doesn't use HARDLOCKUP_DETECTOR the same way x86 does. As a result break
out the new functions
watchdog_hardlockup_detector_is_enabled
watchdog_enable_hardlockup_detector
into their own #if defined area. This resolves the compile issue where
CONFIG_NMI_WATCHDOG=y and CONFIG_HARDLOCKUP_DETECTOR is not set on sparc.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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fix build
In file included from arch/x86/mm/init_64.c:33:
include/linux/nmi.h: In function 'watchdog_enable_hardlockup_detector':
include/linux/nmi.h:27: error: parameter name omitted
Cc: Andrew Jones <drjones@redhat.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In some cases we don't want hard lockup detection enabled by default. An
example is when running as a guest. Introduce
watchdog_enable_hardlockup_detector(bool)
allowing those cases to disable hard lockup detection. This must be
executed early by the boot processor from e.g. smp_prepare_boot_cpu, in
order to allow kernel command line arguments to override it, as well as to
avoid hard lockup detection being enabled before we've had a chance to
indicate that it's unwanted. In summary,
initial boot: default=enabled
smp_prepare_boot_cpu
watchdog_enable_hardlockup_detector(false): default=disabled
cmdline has 'nmi_watchdog=1': default=enabled
The running kernel still has the ability to enable/disable at any time
with /proc/sys/kernel/nmi_watchdog us usual. However even when the
default has been overridden /proc/sys/kernel/nmi_watchdog will initially
show '1'. To truly turn it on one must disable/enable it, i.e.
echo 0 > /proc/sys/kernel/nmi_watchdog
echo 1 > /proc/sys/kernel/nmi_watchdog
This patch will be immediately useful for KVM with the next patch of this
series. Other hypervisor guest types may find it useful as well.
Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Let's use kernel's native specifier to escape a buffer.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Let's use kernel's native specifier to escape a buffer.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This is a generic specifier to print an escaped buffer by given criteria.
Let's use it instead of custom approach.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In kernel we have %*pE specifier to print an escaped buffer. All users
now switched to that approach.
This fixes a bug as well. The current implementation wrongly prints octal
numbers: only two first digits are used in case when 3 are required and
the rest of the string ends up cut off.
Additionally by default the \f, \v, \a, and \e are escaped to their
alphabetic representation. It's safe to do since it is currently used for
messaging only.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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remove now-unused local `i'
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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drivers/net/wireless/hostap/hostap_proc.c: In function 'prism2_bss_list_proc_show':
drivers/net/wireless/hostap/hostap_proc.c:184: warning: field width should have type 'int', but argument 3 has type 'size_t'
Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Instead of substituting non-printable characters by '_' let's print SSID
properly escaped by using recently added %*pE specifier.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Instead of custom approach this allows to print escaped strings via
recently added kernel extension: %*pE.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Instead of custom approach this allows to print escaped strings via
recently added kernel extension: %*pE.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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tidy up comment layout, per Joe
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This allows user to print a given buffer as an escaped string. The rules
are applied according to an optional mix of flags provided by additional
format letters.
For example, if the given buffer is:
1b 62 20 5c 43 07 22 90 0d 5d
The result strings would be:
%*pE "\eb \C\a"\220\r]"
%*pEhp "\x1bb \C\x07"\x90\x0d]"
%*pEa "\e\142\040\\\103\a\042\220\r\135"
Please, read Documentation/printk-formats.txt and lib/string_helpers.c
kernel documentation to get further information.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Joe Perches <joe@perches.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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avoid 1k stack consumption
Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This is almost the opposite function to string_unescape(). Nevertheless
it handles \0 and could be used for any byte buffer.
The documentation is supplied together with the function prototype.
The test cases covers most of the scenarios and would be expanded later
on.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This patch prepares test suite for a following update. It introduces
test_string_check_buf() helper which checks the result and dumps an error.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The introduced function string_escape_mem() is a kind of opposite to
string_unescape. We have several users of such functionality each of them
created custom implementation. The series contains clean up of test
suite, adding new call, and switching few users to use it via %*pE
specifier.
Test suite covers all of existing and most of potential use cases.
This patch (of 11):
The documentation of API belongs to c-file. This patch moves it
accordingly.
There is no functional change.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Remove obsolete and unused strict_strto* functions
Signed-off-by: Daniel Walter <dwalter@google.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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h-fixes
WARNING: Missing a blank line after declarations
#65: FILE: arch/x86/mm/numa.c:480:
+ struct numa_memblk *mb = &numa_meminfo.blk[i];
+ memblock_set_node(mb->start, mb->end - mb->start,
total: 0 errors, 1 warnings, 112 lines checked
./patches/mem-hotplug-fix-boot-failed-in-case-all-the-nodes-are-hotpluggable.patch has style problems, please review.
If any of these errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.
Please run checkpatch prior to sending patches
Cc: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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If all the nodes are marked hotpluggable, alloc node data will fail.
Because __next_mem_range_rev() will skip the hotpluggable memory regions.
numa_clear_kernel_node_hotplug() is called after alloc node data.
numa_init()
...
ret = init_func(); // this will mark hotpluggable flag from SRAT
...
memblock_set_bottom_up(false);
...
ret = numa_register_memblks(&numa_meminfo); // this will alloc node data(pglist_data)
...
numa_clear_kernel_node_hotplug(); // in case all the nodes are hotpluggable
...
numa_register_memblks()
setup_node_data()
memblock_find_in_range_node()
__memblock_find_range_top_down()
for_each_mem_range_rev()
__next_mem_range_rev()
This patch moves numa_clear_kernel_node_hotplug() into
numa_register_memblks(), clear kernel node hotpluggable flag before alloc
node data, then alloc node data won't fail even all the nodes are
hotpluggable.
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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It's very common for the buffer heads in the lru to have different block
numbers. By comparing the blocknr before the bdev and size we can reduce
the cost of searching in the very common case where all the entries have
the same bdev and size.
In quick hot cache cycle counting tests on a single fs workstation this
cut the cost of a miss by about 20%.
A diff of the disassembly shows the reordering of the bdev and blocknr
comparisons. This is in such a tiny loop that skipping one comparison is
a meaningful portion of the total work being done:
1628: 83 c1 01 add $0x1,%ecx
162b: 83 f9 08 cmp $0x8,%ecx
162e: 74 60 je 1690 <__find_get_block+0xa0>
1630: 89 c8 mov %ecx,%eax
1632: 65 4c 8b 04 c5 00 00 mov %gs:0x0(,%rax,8),%r8
1639: 00 00
163b: 4d 85 c0 test %r8,%r8
163e: 4c 89 c3 mov %r8,%rbx
1641: 74 e5 je 1628 <__find_get_block+0x38>
- 1643: 4d 3b 68 30 cmp 0x30(%r8),%r13
+ 1643: 4d 3b 68 18 cmp 0x18(%r8),%r13
1647: 75 df jne 1628 <__find_get_block+0x38>
- 1649: 4d 3b 60 18 cmp 0x18(%r8),%r12
+ 1649: 4d 3b 60 30 cmp 0x30(%r8),%r12
164d: 75 d9 jne 1628 <__find_get_block+0x38>
164f: 49 39 50 20 cmp %rdx,0x20(%r8)
1653: 75 d3 jne 1628 <__find_get_block+0x38>
Signed-off-by: Zach Brown <zab@zabbo.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and a
slightly buggy strncasecmp. The latter is the POSIX name, so strnicmp was
renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.
To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and a
slightly buggy strncasecmp. The latter is the POSIX name, so strnicmp was
renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.
To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and a
slightly buggy strncasecmp. The latter is the POSIX name, so strnicmp was
renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.
To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and a
slightly buggy strncasecmp. The latter is the POSIX name, so strnicmp was
renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.
To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and a
slightly buggy strncasecmp. The latter is the POSIX name, so strnicmp was
renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.
To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and a
slightly buggy strncasecmp. The latter is the POSIX name, so strnicmp was
renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.
To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Henrique de Moraes Holschuh <ibm-acpi@hmh.eng.br>
Cc: Darren Hart <dvhart@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and a
slightly buggy strncasecmp. The latter is the POSIX name, so strnicmp was
renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.
To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: "Igor M. Liplianin" <liplianin@netup.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and a
slightly buggy strncasecmp. The latter is the POSIX name, so strnicmp was
renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.
To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and a
slightly buggy strncasecmp. The latter is the POSIX name, so strnicmp was
renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.
To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Roland Dreier <roland@kernel.org>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and a
slightly buggy strncasecmp. The latter is the POSIX name, so strnicmp was
renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.
To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and a
slightly buggy strncasecmp. The latter is the POSIX name, so strnicmp was
renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.
To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Marek Lindner <mareklindner@neomailbox.ch>
Acked-by: Antonio Quartulli <antonio@meshcoding.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
The kernel used to contain two functions for length-delimited,
case-insensitive string comparison, strnicmp with correct semantics and a
slightly buggy strncasecmp. The latter is the POSIX name, so strnicmp was
renamed to strncasecmp, and strnicmp made into a wrapper for the new
strncasecmp to avoid breaking existing users.
To allow the compat wrapper strnicmp to be removed at some point in the
future, and to avoid the extra indirection cost, do
s/strnicmp/strncasecmp/g.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
