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-rw-r--r--drivers/s390/cio/qdio_main.c31
1 files changed, 20 insertions, 11 deletions
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 6b340e6e29ac..bd26df85f559 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -214,7 +214,10 @@ again:
return 0;
}
-/* returns number of examined buffers and their common state in *state */
+/*
+ * Returns number of examined buffers and their common state in *state.
+ * Requested number of buffers-to-examine must be > 0.
+ */
static inline int get_buf_states(struct qdio_q *q, unsigned int bufnr,
unsigned char *state, unsigned int count,
int auto_ack, int merge_pending)
@@ -225,17 +228,23 @@ static inline int get_buf_states(struct qdio_q *q, unsigned int bufnr,
if (is_qebsm(q))
return qdio_do_eqbs(q, state, bufnr, count, auto_ack);
- for (i = 0; i < count; i++) {
- if (!__state) {
- __state = q->slsb.val[bufnr];
- if (merge_pending && __state == SLSB_P_OUTPUT_PENDING)
- __state = SLSB_P_OUTPUT_EMPTY;
- } else if (merge_pending) {
- if ((q->slsb.val[bufnr] & __state) != __state)
- break;
- } else if (q->slsb.val[bufnr] != __state)
- break;
+ /* get initial state: */
+ __state = q->slsb.val[bufnr];
+ if (merge_pending && __state == SLSB_P_OUTPUT_PENDING)
+ __state = SLSB_P_OUTPUT_EMPTY;
+
+ for (i = 1; i < count; i++) {
bufnr = next_buf(bufnr);
+
+ /* merge PENDING into EMPTY: */
+ if (merge_pending &&
+ q->slsb.val[bufnr] == SLSB_P_OUTPUT_PENDING &&
+ __state == SLSB_P_OUTPUT_EMPTY)
+ continue;
+
+ /* stop if next state differs from initial state: */
+ if (q->slsb.val[bufnr] != __state)
+ break;
}
*state = __state;
return i;