This patch open codes the bitmap_weight() call. The direct
invocation of hweight_long() allows to remove the BUG_ON and
excessive "longs to bits, bits to longs" conversion.
BUG_ON was required to check that bitmap_weight() will return
a correct value, i.e. the computed weight will fit the int type
of the return value. With this patch memweight() controls the
computation directly with size_t type everywhere. Thus, the BUG_ON
becomes unnecessary.
Total size reduced:
./scripts/bloat-o-meter lib/memweight.o.old lib/memweight.o.new
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-10 (-10)
Function old new delta
memweight 162 152 -10
Co-developed-by: Erdem Tumurov <erdemus@xxxxxxxxx>
Signed-off-by: Erdem Tumurov <erdemus@xxxxxxxxx>
Co-developed-by: Vladimir Shelekhov <vshel@xxxxxxxxxx>
Signed-off-by: Vladimir Shelekhov <vshel@xxxxxxxxxx>
Signed-off-by: Denis Efremov <efremov@xxxxxxxxx>
---
lib/memweight.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/lib/memweight.c b/lib/memweight.c
index 94dd72ccaa7f..f050b2b4c5e2 100644
--- a/lib/memweight.c
+++ b/lib/memweight.c
@@ -20,11 +20,13 @@ size_t memweight(const void *ptr, size_t bytes)
longs = bytes / sizeof(long);
if (longs) {
- BUG_ON(longs >= INT_MAX / BITS_PER_LONG);
- ret += bitmap_weight((unsigned long *)bitmap,
- longs * BITS_PER_LONG);
+ const unsigned long *bitmap_long =
+ (const unsigned long *)bitmap;
+
bytes -= longs * sizeof(long);
- bitmap += longs * sizeof(long);
+ for (; longs > 0; longs--, bitmap_long++)
+ ret += hweight_long(*bitmap_long);
+ bitmap = (const unsigned char *)bitmap_long;
}
/*
* The reason that this last loop is distinct from the preceding
--
2.21.0
