In most real-life cases, 0-length bitmap provided by user is a sign of
an error. The API doesn't provide any guarantees on returned value, and
the bitmap pointers are not dereferenced.
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Bitmap API handles nbits == 0 in most cases correctly, i.e. it doesn't
dereferene underlying bitmap and returns a sane value where convenient,
or implementation defined, or undef.
Implicitly testing nbits == 0 case, however, may make an impression that
this is a regular case. This is wrong. In most cases nbits == 0 is a
sign of an error on a client side. The tests should not make such an
implression.
This patch reworks the existing tests to not test nbits == 0. The
following patch adds an explicit test for it with an appropriate
precaution.
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Test the function for correctness when some bits are set in the last word
of bitmap beyond nbits. This is motivated by commit a9dadc1c51
("powerpc/xive: Fix the size of the cpumask used in
xive_find_target_in_mask()").
Signed-off-by: Yury Norov <ynorov@nvidia.com>
scnprintf("%*pbl") is more verbose than bitmap_print_to_pagebuf().
Switch the test to using it. This also improves the test output
because bitmap_print_to_pagebuf() adds \n at the end of the printed
bitmap, which breaks the test format.
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Make sure that bitmap_scatter() and bitmap_gather() do not modify
the bits outside of the given nbits span.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yury Norov <ynorov@nvidia.com>
make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/find_bit_benchmark.o
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/cpumask_kunit.o
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/test_bitmap.o
Add the missing invocations of the MODULE_DESCRIPTION() macro.
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Pull bitmap updates from Yury Norov:
- topology_span_sane() optimization from Kyle Meyer
- fns() rework from Kuan-Wei Chiu (used in cpumask_local_spread() and
other places)
- headers cleanup from Andy
- add a MAINTAINERS record for bitops API
* tag 'bitmap-for-6.10v2' of https://github.com/norov/linux:
usercopy: Don't use "proxy" headers
bitops: Move aligned_byte_mask() to wordpart.h
MAINTAINERS: add BITOPS API record
bitmap: relax find_nth_bit() limitation on return value
lib: make test_bitops compilable into the kernel image
bitops: Optimize fns() for improved performance
lib/test_bitops: Add benchmark test for fns()
Compiler Attributes: Add __always_used macro
sched/topology: Optimize topology_span_sane()
cpumask: Add for_each_cpu_from()
Commit dc34d50366 ("lib: test_bitmap: add compile-time
optimization/evaluations assertions") initially missed __assign_bit(),
which led to that quite a time passed before I realized it doesn't get
optimized at compilation time. Now that it does, add test for that just
to make sure nothing will break one day.
To make things more interesting, use bitmap_complement() and
bitmap_full(), thus checking their compile-time evaluation as well. And
remove the misleading comment mentioning the workaround removed recently
in favor of adding the whole file to GCov exceptions.
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add basic tests ensuring that values can be added at arbitrary positions
of the bitmap, including those spanning into the adjacent unsigned
longs.
Two new performance tests, test_bitmap_read_perf() and
test_bitmap_write_perf(), can be used to assess future performance
improvements of bitmap_read() and bitmap_write():
[ 0.431119][ T1] test_bitmap: Time spent in test_bitmap_read_perf: 615253
[ 0.433197][ T1] test_bitmap: Time spent in test_bitmap_write_perf: 916313
(numbers from a Intel(R) Xeon(R) Gold 6154 CPU @ 3.00GHz machine running
QEMU).
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
These helpers scatters or gathers a bitmap with the help of the mask
position bits parameter.
bitmap_scatter() does the following:
src: 0000000001011010
||||||
+------+|||||
| +----+||||
| |+----+|||
| || +-+||
| || | ||
mask: ...v..vv...v..vv
...0..11...0..10
dst: 0000001100000010
and bitmap_gather() performs this one:
mask: ...v..vv...v..vv
src: 0000001100000010
^ ^^ ^ 0
| || | 10
| || > 010
| |+--> 1010
| +--> 11010
+----> 011010
dst: 0000000000011010
bitmap_gather() can the seen as the reverse bitmap_scatter() operation.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/lkml/20230926052007.3917389-3-andriy.shevchenko@linux.intel.com/
Co-developed-by: Herve Codina <herve.codina@bootlin.com>
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When building with Clang, and when KASAN and GCOV_PROFILE_ALL are both
enabled, the test fails to build [1]:
>> lib/test_bitmap.c:920:2: error: call to '__compiletime_assert_239' declared with 'error' attribute: BUILD_BUG_ON failed: !__builtin_constant_p(res)
BUILD_BUG_ON(!__builtin_constant_p(res));
^
include/linux/build_bug.h:50:2: note: expanded from macro 'BUILD_BUG_ON'
BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
^
include/linux/build_bug.h:39:37: note: expanded from macro 'BUILD_BUG_ON_MSG'
#define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
^
include/linux/compiler_types.h:352:2: note: expanded from macro 'compiletime_assert'
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^
include/linux/compiler_types.h:340:2: note: expanded from macro '_compiletime_assert'
__compiletime_assert(condition, msg, prefix, suffix)
^
include/linux/compiler_types.h:333:4: note: expanded from macro '__compiletime_assert'
prefix ## suffix(); \
^
<scratch space>:185:1: note: expanded from here
__compiletime_assert_239
Originally it was attributed to s390, which now looks seemingly wrong. The
issue is not related to bitmap code itself, but it breaks build for a given
configuration.
Disabling the const_eval test under that config may potentially hide other
bugs. Instead, workaround it by disabling GCOV for the test_bitmap unless
the compiler will get fixed.
[1] https://github.com/ClangBuiltLinux/linux/issues/1874
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202307171254.yFcH97ej-lkp@intel.com/
Fixes: dc34d50366 ("lib: test_bitmap: add compile-time optimization/evaluations assertions")
Co-developed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Currently, test_bitmap_arr64() only tests bitmap_to_arr64()'s sanity
by comparing the result of double-conversion (bm -> arr64 -> bm2)
with the input bitmap. However, this may be not enough when one side
hides bugs of the second one (e.g. tail clearing, which is being
performed by both).
Expand the tests and check the tail of the actual arr64 used as
a temporary buffer for double-converting.
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Add a function to the bitmap test suite, which will ensure that
compilers are able to evaluate operations performed by the
bitops/bitmap helpers to compile-time constants when all of the
arguments are compile-time constants as well, or trigger a build
bug otherwise. This should work on all architectures and all the
optimization levels supported by Kbuild.
The function doesn't perform any runtime tests and gets optimized
out to nothing after passing the build assertions.
Unfortunately, Clang for s390 is currently broken (up to the latest
Git snapshots) -- see the comment in the code -- so for now there's
a small workaround for it which doesn't alter the logics. Hope we'll
be able to remove it one day (bugreport is on its way).
Suggested-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Functional tests for bitmap_print_to_pagebuf() are provided
in lib/test_printf.c. This patch adds performance test for
a case of fully set bitmap.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Yury Norov
Andy ShevchenkoandYury Norov
Tamir DubersteinandYury Norov
Jeff JohnsonandYury Norov
Linus Torvalds
Alexander LobakinandDavid S. Miller
Alexander PotapenkoandDavid S. Miller
Alexander LobakinandYury Norov
Barry SongandGreg Kroah-Hartman