[PATCH] KVM: i8254: drop local copy of mul_u64_u32_div

Paolo Bonzini
2016-03-04T08:28:53Z

A function that does the same as i8254.c's muldiv64 has been added
(for KVM's own use, in fact!) in include/linux/math64.h. Use it
instead of muldiv64.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/i8254.c | 26 +++-----------------------
1 file changed, 3 insertions(+), 23 deletions(-)

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 219ef855aae5..a4bf5b45d65a 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -51,26 +51,6 @@
#define RW_STATE_WORD0 3
#define RW_STATE_WORD1 4

-/* Compute with 96 bit intermediate result: (a*b)/c */
-static u64 muldiv64(u64 a, u32 b, u32 c)
-{
- union {
- u64 ll;
- struct {
- u32 low, high;
- } l;
- } u, res;
- u64 rl, rh;
-
- u.ll = a;
- rl = (u64)u.l.low * (u64)b;
- rh = (u64)u.l.high * (u64)b;
- rh += (rl >> 32);
- res.l.high = div64_u64(rh, c);
- res.l.low = div64_u64(((mod_64(rh, c) << 32) + (rl & 0xffffffff)), c);
- return res.ll;
-}
-
static void pit_set_gate(struct kvm_pit *pit, int channel, u32 val)
{
struct kvm_kpit_channel_state *c = &pit->pit_state.channels[channel];
@@ -139,7 +119,7 @@ static int pit_get_count(struct kvm_pit *pit, int channel)
int counter;

t = kpit_elapsed(pit, c, channel);
- d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
+ d = mul_u64_u32_div(t, KVM_PIT_FREQ, NSEC_PER_SEC);

switch (c->mode) {
case 0:
@@ -166,7 +146,7 @@ static int pit_get_out(struct kvm_pit *pit, int channel)
int out;

t = kpit_elapsed(pit, c, channel);
- d = muldiv64(t, KVM_PIT_FREQ, NSEC_PER_SEC);
+ d = mul_u64_u32_div(t, KVM_PIT_FREQ, NSEC_PER_SEC);

switch (c->mode) {
default:
@@ -338,7 +318,7 @@ static void create_pit_timer(struct kvm_pit *pit, u32 val, int is_period)
ps->flags & KVM_PIT_FLAGS_HPET_LEGACY)
return;

- interval = muldiv64(val, NSEC_PER_SEC, KVM_PIT_FREQ);
+ interval = mul_u64_u32_div(val, NSEC_PER_SEC, KVM_PIT_FREQ);

pr_debug("create pit timer, interval is %llu nsec\n", interval);

--
1.8.3.1