Use "mask" instead of a dedicated boolean to track whether or not there
is at least one to-be-reset entry for the current slot+offset. In the
body of the loop, mask is zero only on the first iteration, i.e. !mask is
equivalent to first_round.
Opportunstically combine the adjacent "if (mask)" statements into a single
if-statement.
No function change intended.
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Yan Zhao <yan.y.zhao@xxxxxxxxx>
Cc: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
virt/kvm/dirty_ring.c | 60 +++++++++++++++++++++----------------------
1 file changed, 29 insertions(+), 31 deletions(-)
diff --git a/virt/kvm/dirty_ring.c b/virt/kvm/dirty_ring.c
index 95ab0e3cf9da..9b23f86ff7b6 100644
--- a/virt/kvm/dirty_ring.c
+++ b/virt/kvm/dirty_ring.c
@@ -108,7 +108,6 @@ int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring,
u64 cur_offset, next_offset;
unsigned long mask = 0;
struct kvm_dirty_gfn *entry;
- bool first_round = true;
while (likely((*nr_entries_reset) < INT_MAX)) {
if (signal_pending(current))
@@ -128,42 +127,42 @@ int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring,
ring->reset_index++;
(*nr_entries_reset)++;
- /*
- * While the size of each ring is fixed, it's possible for the
- * ring to be constantly re-dirtied/harvested while the reset
- * is in-progress (the hard limit exists only to guard against
- * wrapping the count into negative space).
- */
- if (!first_round)
+ if (mask) {
+ /*
+ * While the size of each ring is fixed, it's possible
+ * for the ring to be constantly re-dirtied/harvested
+ * while the reset is in-progress (the hard limit exists
+ * only to guard against the count becoming negative).
+ */
cond_resched();
- /*
- * Try to coalesce the reset operations when the guest is
- * scanning pages in the same slot.
- */
- if (!first_round && next_slot == cur_slot) {
- s64 delta = next_offset - cur_offset;
+ /*
+ * Try to coalesce the reset operations when the guest
+ * is scanning pages in the same slot.
+ */
+ if (next_slot == cur_slot) {
+ s64 delta = next_offset - cur_offset;
- if (delta >= 0 && delta < BITS_PER_LONG) {
- mask |= 1ull << delta;
- continue;
- }
+ if (delta >= 0 && delta < BITS_PER_LONG) {
+ mask |= 1ull << delta;
+ continue;
+ }
- /* Backwards visit, careful about overflows! */
- if (delta > -BITS_PER_LONG && delta < 0 &&
- (mask << -delta >> -delta) == mask) {
- cur_offset = next_offset;
- mask = (mask << -delta) | 1;
- continue;
+ /* Backwards visit, careful about overflows! */
+ if (delta > -BITS_PER_LONG && delta < 0 &&
+ (mask << -delta >> -delta) == mask) {
+ cur_offset = next_offset;
+ mask = (mask << -delta) | 1;
+ continue;
+ }
}
- }
- /*
- * Reset the slot for all the harvested entries that have been
- * gathered, but not yet fully processed.
- */
- if (mask)
+ /*
+ * Reset the slot for all the harvested entries that
+ * have been gathered, but not yet fully processed.
+ */
kvm_reset_dirty_gfn(kvm, cur_slot, cur_offset, mask);
+ }
/*
* The current slot was reset or this is the first harvested
@@ -172,7 +171,6 @@ int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring,
cur_slot = next_slot;
cur_offset = next_offset;
mask = 1;
- first_round = false;
}
/*
--
2.47.1.613.gc27f4b7a9f-goog
