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syzbot is catching stalls at __bitmap_parselist()
(https://syzkaller.appspot.com/bug?id=ad7e0351fbc90535558514a71cd3edc11681997a).
The trigger is
unsigned long v = 0;
bitmap_parselist("7:,", &v, BITS_PER_LONG);
which results in hitting infinite loop at
while (a <= b) {
off = min(b - a + 1, used_size);
bitmap_set(maskp, a, off);
a += group_size;
}
due to used_size == group_size == 0.
Link: http://lkml.kernel.org/r/20180404162647.15763-1-ynorov@caviumnetworks.com
Fixes: 0a5ce0831d04382a ("lib/bitmap.c: make bitmap_parselist() thread-safe and much faster")
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+6887cbb011c8054e8a3d@syzkaller.appspotmail.com>
Cc: Noam Camus <noamca@mellanox.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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with bitmap_{from,to}_arr32 over the kernel. Additionally to it:
* __check_eq_bitmap() now takes single nbits argument.
* __check_eq_u32_array is not used in new test but may be used in
future. So I don't remove it here, but annotate as __used.
Tested on arm64 and 32-bit BE mips.
[arnd@arndb.de: perf: arm_dsu_pmu: convert to bitmap_from_arr32]
Link: http://lkml.kernel.org/r/20180201172508.5739-2-ynorov@caviumnetworks.com
[ynorov@caviumnetworks.com: fix net/core/ethtool.c]
Link: http://lkml.kernel.org/r/20180205071747.4ekxtsbgxkj5b2fz@yury-thinkpad
Link: http://lkml.kernel.org/r/20171228150019.27953-2-ynorov@caviumnetworks.com
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: David Decotigny <decot@googlers.com>,
Cc: David S. Miller <davem@davemloft.net>,
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patchset replaces bitmap_{to,from}_u32array with more simple and
standard looking copy-like functions.
bitmap_from_u32array() takes 4 arguments (bitmap_to_u32array is similar):
- unsigned long *bitmap, which is destination;
- unsigned int nbits, the length of destination bitmap, in bits;
- const u32 *buf, the source; and
- unsigned int nwords, the length of source buffer in ints.
In description to the function it is detailed like:
* copy min(nbits, 32*nwords) bits from @buf to @bitmap, remaining
* bits between nword and nbits in @bitmap (if any) are cleared.
Having two size arguments looks unneeded and potentially dangerous.
It is unneeded because normally user of copy-like function should take
care of the size of destination and make it big enough to fit source
data.
And it is dangerous because function may hide possible error if user
doesn't provide big enough bitmap, and data becomes silently dropped.
That's why all copy-like functions have 1 argument for size of copying
data, and I don't see any reason to make bitmap_from_u32array()
different.
One exception that comes in mind is strncpy() which also provides size
of destination in arguments, but it's strongly argued by the possibility
of taking broken strings in source. This is not the case of
bitmap_{from,to}_u32array().
There is no many real users of bitmap_{from,to}_u32array(), and they all
very clearly provide size of destination matched with the size of
source, so additional functionality is not used in fact. Like this:
bitmap_from_u32array(to->link_modes.supported,
__ETHTOOL_LINK_MODE_MASK_NBITS,
link_usettings.link_modes.supported,
__ETHTOOL_LINK_MODE_MASK_NU32);
Where:
#define __ETHTOOL_LINK_MODE_MASK_NU32 \
DIV_ROUND_UP(__ETHTOOL_LINK_MODE_MASK_NBITS, 32)
In this patch, bitmap_copy_safe and bitmap_{from,to}_arr32 are introduced.
'Safe' in bitmap_copy_safe() stands for clearing unused bits in bitmap
beyond last bit till the end of last word. It is useful for hardening
API when bitmap is assumed to be exposed to userspace.
bitmap_{from,to}_arr32 functions are replacements for
bitmap_{from,to}_u32array. They don't take unneeded nwords argument, and
so simpler in implementation and understanding.
This patch suggests optimization for 32-bit systems - aliasing
bitmap_{from,to}_arr32 to bitmap_copy_safe.
Other possible optimization is aliasing 64-bit LE bitmap_{from,to}_arr32 to
more generic function(s). But I didn't end up with the function that would
be helpful by itself, and can be used to alias 64-bit LE
bitmap_{from,to}_arr32, like bitmap_copy_safe() does. So I preferred to
leave things as is.
The following patch switches kernel to new API and introduces test for it.
Discussion is here: https://lkml.org/lkml/2017/11/15/592
[ynorov@caviumnetworks.com: rename bitmap_copy_safe to bitmap_copy_clear_tail]
Link: http://lkml.kernel.org/r/20180201172508.5739-3-ynorov@caviumnetworks.com
Link: http://lkml.kernel.org/r/20171228150019.27953-1-ynorov@caviumnetworks.com
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: David Decotigny <decot@googlers.com>,
Cc: David S. Miller <davem@davemloft.net>,
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There are some good comments about bitmap operations in lib/bitmap.c
and include/linux/bitmap.h, so format them for document generation and
pull them into core-api/kernel-api.rst.
I converted the "tables" of functions from using tabs to using spaces
so that they are more readable in the source file and in the generated
output.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Current implementation of bitmap_parselist() uses a static variable to
save local state while setting bits in the bitmap. It is obviously wrong
if we assume execution in multiprocessor environment. Fortunately, it's
possible to rewrite this portion of code to avoid using the static
variable.
It is also possible to set bits in the mask per-range with bitmap_set(),
not per-bit, as it is implemented now, with set_bit(); which is way
faster.
The important side effect of this change is that setting bits in this
function from now is not per-bit atomic and less memory-ordered. This is
because set_bit() guarantees the order of memory accesses, while
bitmap_set() does not. I think that it is the advantage of the new
approach, because the bitmap_parselist() is intended to initialise bit
arrays, and user should protect the whole bitmap during initialisation if
needed. So protecting individual bits looks expensive and useless. Also,
other range-oriented functions in lib/bitmap.c don't worry much about
atomicity.
With all that, setting 2k bits in map with the pattern like 0-2047:128/256
becomes ~50 times faster after applying the patch in my testing
environment (arm64 hosted on qemu).
The second patch of the series adds the test for bitmap_parselist(). It's
not intended to cover all tricky cases, just to make sure that I didn't
screw up during rework.
Link: http://lkml.kernel.org/r/20170807225438.16161-1-ynorov@caviumnetworks.com
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Cc: Noam Camus <noamca@mellanox.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We have eight users calling bitmap_clear for a single bit and seventeen
calling bitmap_set for a single bit. Rather than fix all of them to
call __clear_bit or __set_bit, turn bitmap_clear and bitmap_set into
inline functions and make this special case efficient.
Link: http://lkml.kernel.org/r/20170628153221.11322-3-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix the following issues:
./lib/bitmap.c:869: WARNING: Definition list ends without a blank line; unexpected unindent.
./lib/bitmap.c:876: WARNING: Inline emphasis start-string without end-string.
./lib/bitmap.c:508: ERROR: Unexpected indentation.
And make sure that a table and a footnote will use the right tags.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
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Today there are platforms with many CPUs (up to 4K). Trying to boot only
part of the CPUs may result in too long string.
For example lets take NPS platform that is part of arch/arc. This
platform have SMP system with 256 cores each with 16 HW threads (SMT
machine) where HW thread appears as CPU to the kernel. In this example
there is total of 4K CPUs. When one tries to boot only part of the HW
threads from each core the string representing the map may be long... For
example if for sake of performance we decided to boot only first half of
HW threads of each core the map will look like:
0-7,16-23,32-39,...,4080-4087
This patch introduce new syntax to accommodate with such use case. I
added an optional postfix to a range of CPUs which will choose according
to given modulo the desired range of reminders i.e.:
<cpus range>:sed_size/group_size
For example, above map can be described in new syntax like this:
0-4095:8/16
Note that this patch is backward compatible with current syntax.
[akpm@linux-foundation.org: rework documentation]
Link: http://lkml.kernel.org/r/1473579629-4283-1-git-send-email-noamca@mellanox.com
Signed-off-by: Noam Camus <noamca@mellanox.com>
Cc: David Decotigny <decot@googlers.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: David S. Miller <davem@davemloft.net>
Cc: Pan Xinhui <xinhui@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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struct thread_info is a legacy mess. To prepare for its partial removal,
move thread_info::addr_limit out.
As an added benefit, this way is simpler.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/15bee834d09402b47ac86f2feccdf6529f9bc5b0.1468527351.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Aimed at transferring bitmaps to/from user-space in a 32/64-bit agnostic
way.
Tested:
unit tests (next patch) on qemu i386, x86_64, ppc, ppc64 BE and LE,
ARM.
Signed-off-by: David Decotigny <decot@googlers.com>
Reviewed-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
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tail
In __bitmap_parselist we can accept whitespaces on head or tail during
every parsing procedure. If input has valid ranges, there is no reason to
reject the user.
For example, bitmap_parselist(" 1-3, 5, ", &mask, nmaskbits). After
separating the string, we get " 1-3", " 5", and " ". It's possible and
reasonable to accept such string as long as the parsing result is correct.
Signed-off-by: Pan Xinhui <xinhuix.pan@intel.com>
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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If string end with '-', for exapmle, bitmap_parselist("1,0-",&mask,
nmaskbits), It is not in a valid pattern, so add a check after loop.
Return -EINVAL on such condition.
Signed-off-by: Pan Xinhui <xinhuix.pan@intel.com>
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We can avoid in-loop incrementation of ndigits. Save current totaldigits
to ndigits before loop, and check ndigits against totaldigits after the
loop.
Signed-off-by: Pan Xinhui <xinhuix.pan@intel.com>
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bitmap_print_to_pagebuf uses scnprintf to copy the cpumask/list to page
buffer. It handles the newline and trailing null character explicitly.
It's unnecessary and also partially duplicated as scnprintf already adds
trailing null character. The newline can be passed through format
string to scnprintf. This patch does that simplification.
However theoretically there's one behavior difference: when the buffer
is too small, the original code would still output '\n' at the end while
the new code(with this patch) would just continue to print the formatted
string. Since this function is dealing with only page buffers, it's
highly unlikely to hit that corner case.
This patch will help in auditing the users of bitmap_print_to_pagebuf to
verify that the buffer passed is large enough and get rid of it
completely by replacing them with direct scnprintf()
[akpm@linux-foundation.org: tweak comment]
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Suggested-by: Pawel Moll <Pawel.Moll@arm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bitmap_parselist("", &mask, nmaskbits) will erroneously set bit zero in
the mask. The same bug is visible in cpumask_parselist() since it is
layered on top of the bitmask code, e.g. if you boot with "isolcpus=",
you will actually end up with cpu zero isolated.
The bug was introduced in commit 4b060420a596 ("bitmap, irq: add
smp_affinity_list interface to /proc/irq") when bitmap_parselist() was
generalized to support userspace as well as kernelspace.
Fixes: 4b060420a596 ("bitmap, irq: add smp_affinity_list interface to /proc/irq")
Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bitmap_empty() has its own implementation. But it's clearly as simple as:
find_first_bit(src, nbits) == nbits
The same is true for 'bitmap_full'.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Cc: George Spelvin <linux@horizon.com>
Cc: Alexey Klimov <klimov.linux@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Now that all bitmap formatting usages have been converted to
'%*pb[l]', the separate formatting functions are unnecessary. The
following functions are removed.
* bitmap_scn[list]printf()
* cpumask_scnprintf(), cpulist_scnprintf()
* [__]nodemask_scnprintf(), [__]nodelist_scnprintf()
* seq_bitmap[_list](), seq_cpumask[_list](), seq_nodemask[_list]()
* seq_buf_bitmask()
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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printk and friends can now format bitmaps using '%*pb[l]'. cpumask
and nodemask also provide cpumask_pr_args() and nodemask_pr_args()
respectively which can be used to generate the two printf arguments
necessary to format the specified cpu/nodemask.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bitmap and its derivatives such as cpumask and nodemask currently only
provide formatting functions which put the output string into the
provided buffer; however, how long this buffer should be isn't defined
anywhere and given that some of these bitmaps can be too large to be
formatted into an on-stack buffer it users sometimes are unnecessarily
forced to come up with creative solutions and compromises for the
buffer just to printk these bitmaps.
There have been a couple different attempts at making this easier.
1. Way back, PeterZ tried printk '%pb' extension with the precision
for bit width - '%.*pb'. This was intuitive and made sense but
unfortunately triggered a compile warning about using precision
for a pointer.
http://lkml.kernel.org/g/1336577562.2527.58.camel@twins
2. I implemented bitmap_pr_cont[_list]() and its wrappers for cpumask
and nodemask. This works but PeterZ pointed out that pr_cont's
tendency to produce broken lines when multiple CPUs are printing is
bothering considering the usages.
http://lkml.kernel.org/g/1418226774-30215-3-git-send-email-tj@kernel.org
So, this patch is another attempt at teaching printk and friends how
to print bitmaps. It's almost identical to what PeterZ tried with
precision but it uses the field width for the number of bits instead
of precision. The format used is '%*pb[l]', with the optional
trailing 'l' specifying list format instead of hex masks.
This is a valid format string and doesn't trigger compiler warnings;
however, it does make it impossible to specify output field width when
printing bitmaps. I think this is an acceptable trade-off given how
much easier it makes printing bitmaps and that we don't have any
in-kernel user which is using the field width specification. If any
future user wants to use field width with a bitmap, it'd have to
format the bitmap into a string buffer and then print that buffer with
width spec, which isn't different from how it should be done now.
This patch implements bitmap[_list]_string() which are called from the
vsprintf pointer() formatting function. The implementation is mostly
identical to bitmap_scn[list]printf() except that the output is
performed in the vsprintf way. These functions handle formatting into
too small buffers and sprintf() family of functions report the correct
overrun output length.
bitmap_scn[list]printf() are now thin wrappers around scnprintf().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Mike Travis <travis@sgi.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The first of these conditionals is completely redundant: If k == lim-1, we
must have off==0, so the second conditional will also trigger and then it
wouldn't matter if upper had some high bits set. But the second
conditional is in fact also redundant, since it only serves to clear out
some high-order "don't care" bits of dst, about which no guarantee is
made.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We can shift the bits from lower and upper into place before assembling
dst[k + off]; moving the shift of lower into the branch where we already
know that rem is non-zero allows us to remove a conditional.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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gcc can generate slightly better code for stuff like "nbits %
BITS_PER_LONG" when it knows nbits is not negative. Since negative size
bitmaps or shift amounts don't make sense, change these parameters of
bitmap_shift_right to unsigned.
If off >= lim (which requires shift >= nbits), k is initialized with a
large positive value, but since I've let k continue to be signed, the loop
will never run and dst will be zeroed as expected. Inside the loop, k is
guaranteed to be non-negative, so the fact that it is promoted to unsigned
in the various expressions it appears in is harmless.
Also use "shift" and "nbits" consistently for the parameter names.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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If left is 0, we can just let mask be ~0UL, so that anding with it is a
no-op. Conveniently, BITMAP_LAST_WORD_MASK provides precisely what we
need, and we can eliminate left.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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If the condition k==lim-1 is true, we must have off == 0 (otherwise, k
could never become that big). But in that case we have upper == 0 and
hence dst[k] == (src[k] & mask) >> rem. Since mask consists of a
consecutive range of bits starting from the LSB, anding dst[k] with mask
is a no-op.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We can shift the bits from lower and upper into place before assembling
dst[k]; moving the shift of upper into the branch where we already know
that rem is non-zero allows us to remove a conditional.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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I've previously changed the nbits parameter of most bitmap_* functions to
unsigned; now it is bitmap_shift_{left,right}'s turn. This alone saves
some .text, but while at it I found that there were a few other things one
could do. The end result of these seven patches is
$ scripts/bloat-o-meter /tmp/bitmap.o.{old,new}
add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-328 (-328)
function old new delta
__bitmap_shift_right 384 226 -158
__bitmap_shift_left 306 136 -170
and less importantly also a smaller stack footprint
$ stack-o-meter.pl master bitmap
file function old new delta
lib/bitmap.o __bitmap_shift_right 24 8 -16
lib/bitmap.o __bitmap_shift_left 24 0 -24
For each pair of 0 <= shift <= nbits <= 256 I've tested the end result
with a few randomly filled src buffers (including garbage beyond nbits),
in each case verifying that the shift {left,right}-most bits of dst are
zero and the remaining nbits-shift bits correspond to src, so I'm fairly
confident I didn't screw up. That hasn't stopped me from being wrong
before, though.
This patch (of 7):
gcc can generate slightly better code for stuff like "nbits %
BITS_PER_LONG" when it knows nbits is not negative. Since negative size
bitmaps or shift amounts don't make sense, change these parameters of
bitmap_shift_right to unsigned.
The expressions involving "lim - 1" are still ok, since if lim is 0 the
loop is never executed.
Also use "shift" and "nbits" consistently for the parameter names.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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On little-endian, there's no reason to have an extra, presumably less
efficient, way of copying a bitmap.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Make the prototype of bitmap_copy_le the same as bitmap_copy's. All other
bitmap_* functions take unsigned long* parameters; there's no reason this
should be special.
The only current user is the static inline uwb_mas_bm_copy_le, which
already does the void* laundering, so the end users can pass their u8 or
__le32 buffers without a cast.
Furthermore, this allows us to simply let bitmap_copy_le be an alias for
bitmap_copy on little-endian; see next patch.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Also, rename bits to nbits. Both changes for consistency with other
bitmap_* functions.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Make the return value and the ord and nbits parameters of
bitmap_ord_to_pos unsigned.
Also, simplify the implementation and as a side effect make the result
fully defined, returning nbits for ord >= weight, in analogy with what
find_{first,next}_bit does. This is a better sentinel than the former
("unofficial") 0. No current users are affected by this change.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The ordinal of a set bit is simply the number of set bits before it;
counting those doesn't need to be done one bit at a time. While at it,
update the parameters to unsigned int.
It is not completely unthinkable that gcc would see pos as compile-time
constant 0 in one of the uses of bitmap_pos_to_ord. Since the static
inline frontend bitmap_weight doesn't handle nbits==0 correctly (it would
behave exactly as if nbits==BITS_PER_LONG), use __bitmap_weight.
Alternatively, the last line could be spelled bitmap_weight(buf, pos+1)-1,
but this is simpler.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Change the sz and nbits parameters of bitmap_fold to unsigned int for
consistency with other bitmap_* functions, and to save another few bytes
in the generated code.
[akpm@linux-foundation.org: fix kerneldoc]
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Change the nbits parameter of bitmap_onto to unsigned int for consistency
with other bitmap_* functions.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core update from Greg KH:
"Here's the set of driver core patches for 3.19-rc1.
They are dominated by the removal of the .owner field in platform
drivers. They touch a lot of files, but they are "simple" changes,
just removing a line in a structure.
Other than that, a few minor driver core and debugfs changes. There
are some ath9k patches coming in through this tree that have been
acked by the wireless maintainers as they relied on the debugfs
changes.
Everything has been in linux-next for a while"
* tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (324 commits)
Revert "ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries"
fs: debugfs: add forward declaration for struct device type
firmware class: Deletion of an unnecessary check before the function call "vunmap"
firmware loader: fix hung task warning dump
devcoredump: provide a one-way disable function
device: Add dev_<level>_once variants
ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries
ath: use seq_file api for ath9k debugfs files
debugfs: add helper function to create device related seq_file
drivers/base: cacheinfo: remove noisy error boot message
Revert "core: platform: add warning if driver has no owner"
drivers: base: support cpu cache information interface to userspace via sysfs
drivers: base: add cpu_device_create to support per-cpu devices
topology: replace custom attribute macros with standard DEVICE_ATTR*
cpumask: factor out show_cpumap into separate helper function
driver core: Fix unbalanced device reference in drivers_probe
driver core: fix race with userland in device_add()
sysfs/kernfs: make read requests on pre-alloc files use the buffer.
sysfs/kernfs: allow attributes to request write buffer be pre-allocated.
fs: sysfs: return EGBIG on write if offset is larger than file size
...
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Add a bitmap_find_next_zero_area_off() function which works like
bitmap_find_next_zero_area() function except it allows an offset to be
specified when alignment is checked. This lets caller request a bit such
that its number plus the offset is aligned according to the mask.
[gregory.0xf0@gmail.com: Retrieved from https://patchwork.linuxtv.org/patch/6254/ and updated documentation]
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Many sysfs *_show function use cpu{list,mask}_scnprintf to copy cpumap
to the buffer aligned to PAGE_SIZE, append '\n' and '\0' to return null
terminated buffer with newline.
This patch creates a new helper function cpumap_print_to_pagebuf in
cpumask.h using newly added bitmap_print_to_pagebuf and consolidates
most of those sysfs functions using the new helper function.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: x86@kernel.org
Cc: linux-acpi@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If __bitmap_shift_left() or __bitmap_shift_right() are asked to shift by
a multiple of BITS_PER_LONG, they will try to shift a long value by
BITS_PER_LONG bits which is undefined. Change the functions to avoid
the undefined shift.
Coverity id: 1192175
Coverity id: 1192174
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull "trivial tree" updates from Jiri Kosina:
"Usual pile from trivial tree everyone is so eagerly waiting for"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
Remove MN10300_PROC_MN2WS0038
mei: fix comments
treewide: Fix typos in Kconfig
kprobes: update jprobe_example.c for do_fork() change
Documentation: change "&" to "and" in Documentation/applying-patches.txt
Documentation: remove obsolete pcmcia-cs from Changes
Documentation: update links in Changes
Documentation: Docbook: Fix generated DocBook/kernel-api.xml
score: Remove GENERIC_HAS_IOMAP
gpio: fix 'CONFIG_GPIO_IRQCHIP' comments
tty: doc: Fix grammar in serial/tty
dma-debug: modify check_for_stack output
treewide: fix errors in printk
genirq: fix reference in devm_request_threaded_irq comment
treewide: fix synchronize_rcu() in comments
checkstack.pl: port to AArch64
doc: queue-sysfs: minor fixes
init/do_mounts: better syntax description
MIPS: fix comment spelling
powerpc/simpleboot: fix comment
...
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This patch fix spelling typo found in DocBook/kernel-api.xml.
It is because the file is generated from the source comments,
I have to fix the comments in source codes.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Apparently, bitmap_andnot is supposed to return whether the new bitmap
is empty. But it didn't take potential garbage bits in the last word
into account.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Apparently, bitmap_and is supposed to return whether the new bitmap is
empty. But it didn't take potential garbage bits in the last word into
account.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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__reg_op(..., REG_OP_ALLOC) always returns 0, so we might as well use that
and save an instruction.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Changing the pos parameter of __reg_op to unsigned allows the compiler
to generate slightly smaller and simpler code. Also update its callers
bitmap_*_region to receive and pass unsigned int. The return types of
bitmap_find_free_region and bitmap_allocate_region are still int to
allow a negative error code to be returned. An int is certainly capable
of representing any realistic return value.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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A few lines above, it was stated that positions for non-set bits are
mapped to -1, which is obviously also what the code does.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We want len to be the index of the first '\n', or the length of the
string if there is no newline. This is a good example of the usefulness
of strchrnul(). Use that instead, thus eliminating a branch and a call
to strlen().
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The compiler can generate slightly smaller and simpler code when it
knows that "start" is non-negative.
Also, use the names "start" and "len" for the two parameters for
consistency with bitmap_set.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The compiler can generate slightly smaller and simpler code when it
knows that "start" is non-negative.
Also, use the names "start" and "len" for the two parameters in both
header file and implementation, instead of the previous mix.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The compiler can generate slightly smaller and simpler code when it
knows that "nbits" is non-negative. Since no-one passes a negative
bit-count, this shouldn't affect the semantics.
I didn't change the return type, since that might change the semantics
of some expression containing a call to bitmap_weight(). Certainly an
int is capable of holding the result.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The compiler can generate slightly smaller and simpler code when it
knows that "nbits" is non-negative. Since no-one passes a negative
bit-count, this shouldn't affect the semantics.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The compiler can generate slightly smaller and simpler code when it
knows that "nbits" is non-negative. Since no-one passes a negative
bit-count, this shouldn't affect the semantics.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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