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-rw-r--r--drivers/xen/events.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index c8b9d9fc77b5..0b14a9bbbb0a 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1388,14 +1388,21 @@ static void __xen_evtchn_do_upcall(void)
pending_bits = active_evtchns(cpu, s, word_idx);
bit_idx = 0; /* usually scan entire word from start */
+ /*
+ * We scan the starting word in two parts.
+ *
+ * 1st time: start in the middle, scanning the
+ * upper bits.
+ *
+ * 2nd time: scan the whole word (not just the
+ * parts skipped in the first pass) -- if an
+ * event in the previously scanned bits is
+ * pending again it would just be scanned on
+ * the next loop anyway.
+ */
if (word_idx == start_word_idx) {
- /* We scan the starting word in two parts */
if (i == 0)
- /* 1st time: start in the middle */
bit_idx = start_bit_idx;
- else
- /* 2nd time: mask bits done already */
- bit_idx &= (1UL << start_bit_idx) - 1;
}
do {