s390/qdio: limit direct access to first_to_check cursor

Refactor all the low-level helpers to take the first_to_check cursor as
parameter, rather than accessing it directly.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 0ccd3b30af78eb14d934bd80cb50cfde84ab6a6a..045f2aad0b3cf9a3573958d49087181a2c5840e2 100644 (file)
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -415,7 +415,8 @@ static inline void account_sbals(struct qdio_q *q, unsigned int count)
        q->q_stats.nr_sbals[pos]++;
 }
 
-static void process_buffer_error(struct qdio_q *q, int count)
+static void process_buffer_error(struct qdio_q *q, unsigned int start,
+                                int count)
 {
        unsigned char state = (q->is_input_q) ? SLSB_P_INPUT_NOT_INIT :
                                        SLSB_P_OUTPUT_NOT_INIT;
@@ -424,29 +425,29 @@ static void process_buffer_error(struct qdio_q *q, int count)
 
        /* special handling for no target buffer empty */
        if (queue_type(q) == QDIO_IQDIO_QFMT && !q->is_input_q &&
-           q->sbal[q->first_to_check]->element[15].sflags == 0x10) {
+           q->sbal[start]->element[15].sflags == 0x10) {
                qperf_inc(q, target_full);
-               DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "OUTFULL FTC:%02x",
-                             q->first_to_check);
+               DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "OUTFULL FTC:%02x", start);
                goto set;
        }
 
        DBF_ERROR("%4x BUF ERROR", SCH_NO(q));
        DBF_ERROR((q->is_input_q) ? "IN:%2d" : "OUT:%2d", q->nr);
-       DBF_ERROR("FTC:%3d C:%3d", q->first_to_check, count);
+       DBF_ERROR("FTC:%3d C:%3d", start, count);
        DBF_ERROR("F14:%2x F15:%2x",
-                 q->sbal[q->first_to_check]->element[14].sflags,
-                 q->sbal[q->first_to_check]->element[15].sflags);
+                 q->sbal[start]->element[14].sflags,
+                 q->sbal[start]->element[15].sflags);
 
 set:
        /*
         * Interrupts may be avoided as long as the error is present
         * so change the buffer state immediately to avoid starvation.
         */
-       set_buf_states(q, q->first_to_check, state, count);
+       set_buf_states(q, start, state, count);
 }
 
-static inline void inbound_primed(struct qdio_q *q, int count)
+static inline void inbound_primed(struct qdio_q *q, unsigned int start,
+                                 int count)
 {
        int new;
 
@@ -457,7 +458,7 @@ static inline void inbound_primed(struct qdio_q *q, int count)
                if (!q->u.in.polling) {
                        q->u.in.polling = 1;
                        q->u.in.ack_count = count;
-                       q->u.in.ack_start = q->first_to_check;
+                       q->u.in.ack_start = start;
                        return;
                }
 
@@ -465,7 +466,7 @@ static inline void inbound_primed(struct qdio_q *q, int count)
                set_buf_states(q, q->u.in.ack_start, SLSB_P_INPUT_NOT_INIT,
                               q->u.in.ack_count);
                q->u.in.ack_count = count;
-               q->u.in.ack_start = q->first_to_check;
+               q->u.in.ack_start = start;
                return;
        }
 
@@ -473,7 +474,7 @@ static inline void inbound_primed(struct qdio_q *q, int count)
         * ACK the newest buffer. The ACK will be removed in qdio_stop_polling
         * or by the next inbound run.
         */
-       new = add_buf(q->first_to_check, count - 1);
+       new = add_buf(start, count - 1);
        if (q->u.in.polling) {
                /* reset the previous ACK but first set the new one */
                set_buf_state(q, new, SLSB_P_INPUT_ACK);
@@ -488,11 +489,12 @@ static inline void inbound_primed(struct qdio_q *q, int count)
        if (!count)
                return;
        /* need to change ALL buffers to get more interrupts */
-       set_buf_states(q, q->first_to_check, SLSB_P_INPUT_NOT_INIT, count);
+       set_buf_states(q, start, SLSB_P_INPUT_NOT_INIT, count);
 }
 
 static int get_inbound_buffer_frontier(struct qdio_q *q)
 {
+       unsigned int start = q->first_to_check;
        unsigned char state = 0;
        int count;
 
@@ -510,22 +512,22 @@ static int get_inbound_buffer_frontier(struct qdio_q *q)
         * No siga sync here, as a PCI or we after a thin interrupt
         * already sync'ed the queues.
         */
-       count = get_buf_states(q, q->first_to_check, &state, count, 1, 0);
+       count = get_buf_states(q, start, &state, count, 1, 0);
        if (!count)
                return 0;
 
        switch (state) {
        case SLSB_P_INPUT_PRIMED:
-               inbound_primed(q, count);
-               q->first_to_check = add_buf(q->first_to_check, count);
+               inbound_primed(q, start, count);
+               q->first_to_check = add_buf(start, count);
                if (atomic_sub_return(count, &q->nr_buf_used) == 0)
                        qperf_inc(q, inbound_queue_full);
                if (q->irq_ptr->perf_stat_enabled)
                        account_sbals(q, count);
                return count;
        case SLSB_P_INPUT_ERROR:
-               process_buffer_error(q, count);
-               q->first_to_check = add_buf(q->first_to_check, count);
+               process_buffer_error(q, start, count);
+               q->first_to_check = add_buf(start, count);
                if (atomic_sub_return(count, &q->nr_buf_used) == 0)
                        qperf_inc(q, inbound_queue_full);
                if (q->irq_ptr->perf_stat_enabled)
@@ -537,7 +539,7 @@ static int get_inbound_buffer_frontier(struct qdio_q *q)
                if (q->irq_ptr->perf_stat_enabled)
                        q->q_stats.nr_sbal_nop++;
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in nop:%1d %#02x",
-                       q->nr, q->first_to_check);
+                             q->nr, start);
                return 0;
        default:
                WARN_ON_ONCE(1);
@@ -559,6 +561,7 @@ static int qdio_inbound_q_moved(struct qdio_q *q)
 
 static inline int qdio_inbound_q_done(struct qdio_q *q)
 {
+       unsigned int start = q->first_to_check;
        unsigned char state = 0;
 
        if (!atomic_read(&q->nr_buf_used))
@@ -566,7 +569,7 @@ static inline int qdio_inbound_q_done(struct qdio_q *q)
 
        if (need_siga_sync(q))
                qdio_siga_sync_q(q);
-       get_buf_state(q, q->first_to_check, &state, 0);
+       get_buf_state(q, start, &state, 0);
 
        if (state == SLSB_P_INPUT_PRIMED || state == SLSB_P_INPUT_ERROR)
                /* more work coming */
@@ -584,8 +587,7 @@ static inline int qdio_inbound_q_done(struct qdio_q *q)
         * has (probably) not moved (see qdio_inbound_processing).
         */
        if (get_tod_clock_fast() > q->u.in.timestamp + QDIO_INPUT_THRESHOLD) {
-               DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in done:%02x",
-                             q->first_to_check);
+               DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in done:%02x", start);
                return 1;
        } else
                return 0;
@@ -706,6 +708,7 @@ void qdio_inbound_processing(unsigned long data)
 
 static int get_outbound_buffer_frontier(struct qdio_q *q)
 {
+       unsigned int start = q->first_to_check;
        unsigned char state = 0;
        int count;
 
@@ -726,8 +729,7 @@ static int get_outbound_buffer_frontier(struct qdio_q *q)
        if (!count)
                return 0;
 
-       count = get_buf_states(q, q->first_to_check, &state, count, 0,
-                              q->u.out.use_cq);
+       count = get_buf_states(q, start, &state, count, 0, q->u.out.use_cq);
        if (!count)
                return 0;
 
@@ -738,13 +740,13 @@ static int get_outbound_buffer_frontier(struct qdio_q *q)
                        "out empty:%1d %02x", q->nr, count);
 
                atomic_sub(count, &q->nr_buf_used);
-               q->first_to_check = add_buf(q->first_to_check, count);
+               q->first_to_check = add_buf(start, count);
                if (q->irq_ptr->perf_stat_enabled)
                        account_sbals(q, count);
                return count;
        case SLSB_P_OUTPUT_ERROR:
-               process_buffer_error(q, count);
-               q->first_to_check = add_buf(q->first_to_check, count);
+               process_buffer_error(q, start, count);
+               q->first_to_check = add_buf(start, count);
                atomic_sub(count, &q->nr_buf_used);
                if (q->irq_ptr->perf_stat_enabled)
                        account_sbals_error(q, count);