[PATCH v2 02/13] bitops: make BYTES_TO_BITS() treewide-available

Alexander Lobakin
2023-10-16T16:54:24Z

Avoid open-coding that simple expression each time by moving
BYTES_TO_BITS() from the probes code to <linux/bitops.h> to export
it to the rest of the kernel.
Simplify the macro while at it. `BITS_PER_LONG / sizeof(long)` always
equals to %BITS_PER_BYTE, regardless of the target architecture.
Do the same for the tools ecosystem as well (incl. its version of
bitops.h).

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
include/linux/bitops.h | 2 ++
kernel/trace/trace_probe.c | 2 --
tools/include/linux/bitops.h | 2 ++
tools/perf/util/probe-finder.c | 2 --
4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index f7f5a783da2a..e0cd09eb91cd 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -21,6 +21,8 @@
#define BITS_TO_U32(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(u32))
#define BITS_TO_BYTES(nr) __KERNEL_DIV_ROUND_UP(nr, BITS_PER_TYPE(char))

+#define BYTES_TO_BITS(nb) ((nb) * BITS_PER_BYTE)
+
extern unsigned int __sw_hweight8(unsigned int w);
extern unsigned int __sw_hweight16(unsigned int w);
extern unsigned int __sw_hweight32(unsigned int w);
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 4dc74d73fc1d..2b743c1e37db 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -1053,8 +1053,6 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
return ret;
}

-#define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
-
/* Bitfield type needs to be parsed into a fetch function */
static int __parse_bitfield_probe_arg(const char *bf,
const struct fetch_type *t,
diff --git a/tools/include/linux/bitops.h b/tools/include/linux/bitops.h
index f18683b95ea6..bc6600466e7b 100644
--- a/tools/include/linux/bitops.h
+++ b/tools/include/linux/bitops.h
@@ -20,6 +20,8 @@
#define BITS_TO_U32(nr) DIV_ROUND_UP(nr, BITS_PER_TYPE(u32))
#define BITS_TO_BYTES(nr) DIV_ROUND_UP(nr, BITS_PER_TYPE(char))

+#define BYTES_TO_BITS(nb) ((nb) * BITS_PER_BYTE)
+
extern unsigned int __sw_hweight8(unsigned int w);
extern unsigned int __sw_hweight16(unsigned int w);
extern unsigned int __sw_hweight32(unsigned int w);
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index f171360b0ef4..35f66c12ad8a 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -304,8 +304,6 @@ static int convert_variable_location(Dwarf_Die *vr_die, Dwarf_Addr addr,
return ret2;
}

-#define BYTES_TO_BITS(nb) ((nb) * BITS_PER_LONG / sizeof(long))
-
static int convert_variable_type(Dwarf_Die *vr_die,
struct probe_trace_arg *tvar,
const char *cast, bool user_access)
--
2.41.0