diff options
Diffstat (limited to 'drivers/s390/cio/qdio_main.c')
| -rw-r--r-- | drivers/s390/cio/qdio_main.c | 31 |
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; |