[SCSI] zfcp: Cleanup QDIO attachment and improve processing.

Some definitions and structures in the zfcp QDIO processing are
improved by the removal of not required variables and processing steps.
I addition the naming of some variables is changed to make their purpose
more clear.

Signed-off-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

3 files changed, 69 insertions, 139 deletions

diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index 5f502c9cb067..0710c59b80ae 100644
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -732,7 +732,7 @@ static int zfcp_fsf_req_send(struct zfcp_fsf_req *req)
 
         zfcp_reqlist_add(adapter->req_list, req);
 
-        req->qdio_req.qdio_outb_usage = atomic_read(&qdio->req_q.count);
+        req->qdio_req.qdio_outb_usage = atomic_read(&qdio->req_q_free);
         req->issued = get_clock();
         if (zfcp_qdio_send(qdio, &req->qdio_req)) {
                 del_timer(&req->timer);
@@ -2025,7 +2025,7 @@ static void zfcp_fsf_req_trace(struct zfcp_fsf_req *req, struct scsi_cmnd *scsi)
         blktrc.magic = ZFCP_BLK_DRV_DATA_MAGIC;
         if (req->status & ZFCP_STATUS_FSFREQ_ERROR)
                 blktrc.flags |= ZFCP_BLK_REQ_ERROR;
-        blktrc.inb_usage = req->qdio_req.qdio_inb_usage;
+        blktrc.inb_usage = 0;
         blktrc.outb_usage = req->qdio_req.qdio_outb_usage;
 
         if (req->adapter->adapter_features & FSF_FEATURE_MEASUREMENT_DATA &&
@@ -2207,7 +2207,7 @@ int zfcp_fsf_send_fcp_command_task(struct zfcp_unit *unit,
                 return -EBUSY;
 
         spin_lock(&qdio->req_q_lock);
-        if (atomic_read(&qdio->req_q.count) <= 0) {
+        if (atomic_read(&qdio->req_q_free) <= 0) {
                 atomic_inc(&qdio->req_q_full);
                 goto out;
         }
@@ -2407,7 +2407,7 @@ out:
 void zfcp_fsf_reqid_check(struct zfcp_qdio *qdio, int sbal_idx)
 {
         struct zfcp_adapter *adapter = qdio->adapter;
-        struct qdio_buffer *sbal = qdio->resp_q.sbal[sbal_idx];
+        struct qdio_buffer *sbal = qdio->res_q[sbal_idx];
         struct qdio_buffer_element *sbale;
         struct zfcp_fsf_req *fsf_req;
         unsigned long req_id;
@@ -2428,8 +2428,6 @@ void zfcp_fsf_reqid_check(struct zfcp_qdio *qdio, int sbal_idx)
                               req_id, dev_name(&adapter->ccw_device->dev));
 
                 fsf_req->qdio_req.sbal_response = sbal_idx;
-                fsf_req->qdio_req.qdio_inb_usage =
-                        atomic_read(&qdio->resp_q.count);
                 zfcp_fsf_req_complete(fsf_req);
 
                 if (likely(sbale->flags & SBAL_FLAGS_LAST_ENTRY))
diff --git a/drivers/s390/scsi/zfcp_qdio.c b/drivers/s390/scsi/zfcp_qdio.c
index 7ab1ac16a11f..a638278c6025 100644
--- a/drivers/s390/scsi/zfcp_qdio.c
+++ b/drivers/s390/scsi/zfcp_qdio.c
@@ -55,71 +55,46 @@ static void zfcp_qdio_zero_sbals(struct qdio_buffer *sbal[], int first, int cnt)
 static inline void zfcp_qdio_account(struct zfcp_qdio *qdio)
 {
         unsigned long long now, span;
-        int free, used;
+        int used;
 
         spin_lock(&qdio->stat_lock);
         now = get_clock_monotonic();
         span = (now - qdio->req_q_time) >> 12;
-        free = atomic_read(&qdio->req_q.count);
-        used = QDIO_MAX_BUFFERS_PER_Q - free;
+        used = QDIO_MAX_BUFFERS_PER_Q - atomic_read(&qdio->req_q_free);
         qdio->req_q_util += used * span;
         qdio->req_q_time = now;
         spin_unlock(&qdio->stat_lock);
 }
 
 static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
-                              int queue_no, int first, int count,
+                              int queue_no, int idx, int count,
                               unsigned long parm)
 {
         struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
-        struct zfcp_qdio_queue *queue = &qdio->req_q;
 
         if (unlikely(qdio_err)) {
-                zfcp_dbf_hba_qdio(qdio->adapter->dbf, qdio_err, first,
-                                        count);
+                zfcp_dbf_hba_qdio(qdio->adapter->dbf, qdio_err, idx, count);
                 zfcp_qdio_handler_error(qdio, "qdireq1");
                 return;
         }
 
         /* cleanup all SBALs being program-owned now */
-        zfcp_qdio_zero_sbals(queue->sbal, first, count);
+        zfcp_qdio_zero_sbals(qdio->req_q, idx, count);
 
         zfcp_qdio_account(qdio);
-        atomic_add(count, &queue->count);
+        atomic_add(count, &qdio->req_q_free);
         wake_up(&qdio->req_q_wq);
 }
 
-static void zfcp_qdio_resp_put_back(struct zfcp_qdio *qdio, int processed)
-{
-        struct zfcp_qdio_queue *queue = &qdio->resp_q;
-        struct ccw_device *cdev = qdio->adapter->ccw_device;
-        u8 count, start = queue->first;
-        unsigned int retval;
-
-        count = atomic_read(&queue->count) + processed;
-
-        retval = do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, start, count);
-
-        if (unlikely(retval)) {
-                atomic_set(&queue->count, count);
-                zfcp_erp_adapter_reopen(qdio->adapter, 0, "qdrpb_1", NULL);
-        } else {
-                queue->first += count;
-                queue->first %= QDIO_MAX_BUFFERS_PER_Q;
-                atomic_set(&queue->count, 0);
-        }
-}
-
 static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
-                               int queue_no, int first, int count,
+                               int queue_no, int idx, int count,
                                unsigned long parm)
 {
         struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
         int sbal_idx, sbal_no;
 
         if (unlikely(qdio_err)) {
-                zfcp_dbf_hba_qdio(qdio->adapter->dbf, qdio_err, first,
-                                        count);
+                zfcp_dbf_hba_qdio(qdio->adapter->dbf, qdio_err, idx, count);
                 zfcp_qdio_handler_error(qdio, "qdires1");
                 return;
         }
@@ -129,16 +104,16 @@ static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
          * returned by QDIO layer
          */
         for (sbal_no = 0; sbal_no < count; sbal_no++) {
-                sbal_idx = (first + sbal_no) % QDIO_MAX_BUFFERS_PER_Q;
+                sbal_idx = (idx + sbal_no) % QDIO_MAX_BUFFERS_PER_Q;
                 /* go through all SBALEs of SBAL */
                 zfcp_fsf_reqid_check(qdio, sbal_idx);
         }
 
         /*
-         * put range of SBALs back to response queue
-         * (including SBALs which have already been free before)
+         * put SBALs back to response queue
          */
-        zfcp_qdio_resp_put_back(qdio, count);
+        if (do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, idx, count))
+                zfcp_erp_adapter_reopen(qdio->adapter, 0, "qdires2", NULL);
 }
 
 static struct qdio_buffer_element *
@@ -185,17 +160,6 @@ zfcp_qdio_sbale_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
         return zfcp_qdio_sbale_curr(qdio, q_req);
 }
 
-static void zfcp_qdio_undo_sbals(struct zfcp_qdio *qdio,
-                                 struct zfcp_qdio_req *q_req)
-{
-        struct qdio_buffer **sbal = qdio->req_q.sbal;
-        int first = q_req->sbal_first;
-        int last = q_req->sbal_last;
-        int count = (last - first + QDIO_MAX_BUFFERS_PER_Q) %
-                QDIO_MAX_BUFFERS_PER_Q + 1;
-        zfcp_qdio_zero_sbals(sbal, first, count);
-}
-
 /**
  * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
  * @qdio: pointer to struct zfcp_qdio
@@ -218,7 +182,8 @@ int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
                 sbale = zfcp_qdio_sbale_next(qdio, q_req);
                 if (!sbale) {
                         atomic_inc(&qdio->req_q_full);
-                        zfcp_qdio_undo_sbals(qdio, q_req);
+                        zfcp_qdio_zero_sbals(qdio->req_q, q_req->sbal_first,
+                                             q_req->sbal_number);
                         return -EINVAL;
                 }
 
@@ -237,10 +202,8 @@ int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
 
 static int zfcp_qdio_sbal_check(struct zfcp_qdio *qdio)
 {
-        struct zfcp_qdio_queue *req_q = &qdio->req_q;
-
         spin_lock_bh(&qdio->req_q_lock);
-        if (atomic_read(&req_q->count) ||
+        if (atomic_read(&qdio->req_q_free) ||
             !(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
                 return 1;
         spin_unlock_bh(&qdio->req_q_lock);
@@ -289,25 +252,25 @@ int zfcp_qdio_sbal_get(struct zfcp_qdio *qdio)
  */
 int zfcp_qdio_send(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 {
-        struct zfcp_qdio_queue *req_q = &qdio->req_q;
-        int first = q_req->sbal_first;
-        int count = q_req->sbal_number;
         int retval;
-        unsigned int qdio_flags = QDIO_FLAG_SYNC_OUTPUT;
+        u8 sbal_number = q_req->sbal_number;
 
         zfcp_qdio_account(qdio);
 
-        retval = do_QDIO(qdio->adapter->ccw_device, qdio_flags, 0, first,
-                         count);
+        retval = do_QDIO(qdio->adapter->ccw_device, QDIO_FLAG_SYNC_OUTPUT, 0,
+                         q_req->sbal_first, sbal_number);
+
         if (unlikely(retval)) {
-                zfcp_qdio_zero_sbals(req_q->sbal, first, count);
+                zfcp_qdio_zero_sbals(qdio->req_q, q_req->sbal_first,
+                                     sbal_number);
                 return retval;
         }
 
         /* account for transferred buffers */
-        atomic_sub(count, &req_q->count);
-        req_q->first += count;
-        req_q->first %= QDIO_MAX_BUFFERS_PER_Q;
+        atomic_sub(sbal_number, &qdio->req_q_free);
+        qdio->req_q_idx += sbal_number;
+        qdio->req_q_idx %= QDIO_MAX_BUFFERS_PER_Q;
+
         return 0;
 }
 
@@ -329,8 +292,8 @@ static void zfcp_qdio_setup_init_data(struct qdio_initialize *id,
         id->input_handler = zfcp_qdio_int_resp;
         id->output_handler = zfcp_qdio_int_req;
         id->int_parm = (unsigned long) qdio;
-        id->input_sbal_addr_array = (void **) (qdio->resp_q.sbal);
-        id->output_sbal_addr_array = (void **) (qdio->req_q.sbal);
+        id->input_sbal_addr_array = (void **) (qdio->res_q);
+        id->output_sbal_addr_array = (void **) (qdio->req_q);
 
 }
 /**
@@ -343,8 +306,8 @@ static int zfcp_qdio_allocate(struct zfcp_qdio *qdio)
 {
         struct qdio_initialize init_data;
 
-        if (zfcp_qdio_buffers_enqueue(qdio->req_q.sbal) ||
-            zfcp_qdio_buffers_enqueue(qdio->resp_q.sbal))
+        if (zfcp_qdio_buffers_enqueue(qdio->req_q) ||
+            zfcp_qdio_buffers_enqueue(qdio->res_q))
                 return -ENOMEM;
 
         zfcp_qdio_setup_init_data(&init_data, qdio);
@@ -358,34 +321,30 @@ static int zfcp_qdio_allocate(struct zfcp_qdio *qdio)
  */
 void zfcp_qdio_close(struct zfcp_qdio *qdio)
 {
-        struct zfcp_qdio_queue *req_q;
-        int first, count;
+        struct zfcp_adapter *adapter = qdio->adapter;
+        int idx, count;
 
-        if (!(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
+        if (!(atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
                 return;
 
         /* clear QDIOUP flag, thus do_QDIO is not called during qdio_shutdown */
-        req_q = &qdio->req_q;
         spin_lock_bh(&qdio->req_q_lock);
-        atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &qdio->adapter->status);
+        atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &adapter->status);
         spin_unlock_bh(&qdio->req_q_lock);
 
         wake_up(&qdio->req_q_wq);
 
-        qdio_shutdown(qdio->adapter->ccw_device,
-                      QDIO_FLAG_CLEANUP_USING_CLEAR);
+        qdio_shutdown(adapter->ccw_device, QDIO_FLAG_CLEANUP_USING_CLEAR);
 
         /* cleanup used outbound sbals */
-        count = atomic_read(&req_q->count);
+        count = atomic_read(&qdio->req_q_free);
         if (count < QDIO_MAX_BUFFERS_PER_Q) {
-                first = (req_q->first + count) % QDIO_MAX_BUFFERS_PER_Q;
+                idx = (qdio->req_q_idx + count) % QDIO_MAX_BUFFERS_PER_Q;
                 count = QDIO_MAX_BUFFERS_PER_Q - count;
-                zfcp_qdio_zero_sbals(req_q->sbal, first, count);
+                zfcp_qdio_zero_sbals(qdio->req_q, idx, count);
         }
-        req_q->first = 0;
-        atomic_set(&req_q->count, 0);
-        qdio->resp_q.first = 0;
-        atomic_set(&qdio->resp_q.count, 0);
+        qdio->req_q_idx = 0;
+        atomic_set(&qdio->req_q_free, 0);
 }
 
 /**
@@ -397,10 +356,11 @@ int zfcp_qdio_open(struct zfcp_qdio *qdio)
 {
         struct qdio_buffer_element *sbale;
         struct qdio_initialize init_data;
-        struct ccw_device *cdev = qdio->adapter->ccw_device;
+        struct zfcp_adapter *adapter = qdio->adapter;
+        struct ccw_device *cdev = adapter->ccw_device;
         int cc;
 
-        if (atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP)
+        if (atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP)
                 return -EIO;
 
         zfcp_qdio_setup_init_data(&init_data, qdio);
@@ -412,19 +372,18 @@ int zfcp_qdio_open(struct zfcp_qdio *qdio)
                 goto failed_qdio;
 
         for (cc = 0; cc < QDIO_MAX_BUFFERS_PER_Q; cc++) {
-                sbale = &(qdio->resp_q.sbal[cc]->element[0]);
+                sbale = &(qdio->res_q[cc]->element[0]);
                 sbale->length = 0;
                 sbale->flags = SBAL_FLAGS_LAST_ENTRY;
                 sbale->addr = NULL;
         }
 
-        if (do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, 0,
-                     QDIO_MAX_BUFFERS_PER_Q))
+        if (do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, 0, QDIO_MAX_BUFFERS_PER_Q))
                 goto failed_qdio;
 
         /* set index of first avalable SBALS / number of available SBALS */
-        qdio->req_q.first = 0;
-        atomic_set(&qdio->req_q.count, QDIO_MAX_BUFFERS_PER_Q);
+        qdio->req_q_idx = 0;
+        atomic_set(&qdio->req_q_free, QDIO_MAX_BUFFERS_PER_Q);
 
         return 0;
 
@@ -438,7 +397,6 @@ failed_establish:
 
 void zfcp_qdio_destroy(struct zfcp_qdio *qdio)
 {
-        struct qdio_buffer **sbal_req, **sbal_resp;
         int p;
 
         if (!qdio)
@@ -447,12 +405,9 @@ void zfcp_qdio_destroy(struct zfcp_qdio *qdio)
         if (qdio->adapter->ccw_device)
                 qdio_free(qdio->adapter->ccw_device);
 
-        sbal_req = qdio->req_q.sbal;
-        sbal_resp = qdio->resp_q.sbal;
-
         for (p = 0; p < QDIO_MAX_BUFFERS_PER_Q; p += QBUFF_PER_PAGE) {
-                free_page((unsigned long) sbal_req[p]);
-                free_page((unsigned long) sbal_resp[p]);
+                free_page((unsigned long) qdio->req_q[p]);
+                free_page((unsigned long) qdio->res_q[p]);
         }
 
         kfree(qdio);
diff --git a/drivers/s390/scsi/zfcp_qdio.h b/drivers/s390/scsi/zfcp_qdio.h
index 8bb00545f19c..10d0df99dbf4 100644
--- a/drivers/s390/scsi/zfcp_qdio.h
+++ b/drivers/s390/scsi/zfcp_qdio.h
@@ -28,21 +28,11 @@
         (ZFCP_QDIO_MAX_SBALS_PER_REQ * ZFCP_QDIO_MAX_SBALES_PER_SBAL - 2)
 
 /**
- * struct zfcp_qdio_queue - qdio queue buffer, zfcp index and free count
- * @sbal: qdio buffers
- * @first: index of next free buffer in queue
- * @count: number of free buffers in queue
- */
-struct zfcp_qdio_queue {
-        struct qdio_buffer *sbal[QDIO_MAX_BUFFERS_PER_Q];
-        u8                 first;
-        atomic_t           count;
-};
-
-/**
  * struct zfcp_qdio - basic qdio data structure
- * @resp_q: response queue
+ * @res_q: response queue
  * @req_q: request queue
+ * @req_q_idx: index of next free buffer
+ * @req_q_free: number of free buffers in queue
  * @stat_lock: lock to protect req_q_util and req_q_time
  * @req_q_lock: lock to serialize access to request queue
  * @req_q_time: time of last fill level change
@@ -52,8 +42,10 @@ struct zfcp_qdio_queue {
  * @adapter: adapter used in conjunction with this qdio structure
  */
 struct zfcp_qdio {
-        struct zfcp_qdio_queue  resp_q;
-        struct zfcp_qdio_queue  req_q;
+        struct qdio_buffer      *res_q[QDIO_MAX_BUFFERS_PER_Q];
+        struct qdio_buffer      *req_q[QDIO_MAX_BUFFERS_PER_Q];
+        u8                      req_q_idx;
+        atomic_t                req_q_free;
         spinlock_t              stat_lock;
         spinlock_t              req_q_lock;
         unsigned long long      req_q_time;
@@ -73,7 +65,6 @@ struct zfcp_qdio {
  * @sbale_curr: current sbale at creation of this request
  * @sbal_response: sbal used in interrupt
  * @qdio_outb_usage: usage of outbound queue
- * @qdio_inb_usage: usage of inbound queue
  */
 struct zfcp_qdio_req {
         u32     sbtype;
@@ -84,22 +75,9 @@ struct zfcp_qdio_req {
         u8      sbale_curr;
         u8      sbal_response;
         u16     qdio_outb_usage;
-        u16     qdio_inb_usage;
 };
 
 /**
- * zfcp_qdio_sbale - return pointer to sbale in qdio queue
- * @q: queue where to find sbal
- * @sbal_idx: sbal index in queue
- * @sbale_idx: sbale index in sbal
- */
-static inline struct qdio_buffer_element *
-zfcp_qdio_sbale(struct zfcp_qdio_queue *q, int sbal_idx, int sbale_idx)
-{
-        return &q->sbal[sbal_idx]->element[sbale_idx];
-}
-
-/**
  * zfcp_qdio_sbale_req - return pointer to sbale on req_q for a request
  * @qdio: pointer to struct zfcp_qdio
  * @q_rec: pointer to struct zfcp_qdio_req
@@ -108,7 +86,7 @@ zfcp_qdio_sbale(struct zfcp_qdio_queue *q, int sbal_idx, int sbale_idx)
 static inline struct qdio_buffer_element *
 zfcp_qdio_sbale_req(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 {
-        return zfcp_qdio_sbale(&qdio->req_q, q_req->sbal_last, 0);
+        return &qdio->req_q[q_req->sbal_last]->element[0];
 }
 
 /**
@@ -120,8 +98,7 @@ zfcp_qdio_sbale_req(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 static inline struct qdio_buffer_element *
 zfcp_qdio_sbale_curr(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
 {
-        return zfcp_qdio_sbale(&qdio->req_q, q_req->sbal_last,
-                               q_req->sbale_curr);
+        return &qdio->req_q[q_req->sbal_last]->element[q_req->sbale_curr];
 }
 
 /**
@@ -142,25 +119,25 @@ void zfcp_qdio_req_init(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
                         unsigned long req_id, u32 sbtype, void *data, u32 len)
 {
         struct qdio_buffer_element *sbale;
-        int count = min(atomic_read(&qdio->req_q.count),
+        int count = min(atomic_read(&qdio->req_q_free),
                         ZFCP_QDIO_MAX_SBALS_PER_REQ);
 
-        q_req->sbal_first = q_req->sbal_last = qdio->req_q.first;
+        q_req->sbal_first = q_req->sbal_last = qdio->req_q_idx;
         q_req->sbal_number = 1;
         q_req->sbtype = sbtype;
+        q_req->sbale_curr = 1;
         q_req->sbal_limit = (q_req->sbal_first + count - 1)
                                         % QDIO_MAX_BUFFERS_PER_Q;
 
         sbale = zfcp_qdio_sbale_req(qdio, q_req);
         sbale->addr = (void *) req_id;
-        sbale->flags |= SBAL_FLAGS0_COMMAND;
-        sbale->flags |= sbtype;
+        sbale->flags = SBAL_FLAGS0_COMMAND | sbtype;
 
-        q_req->sbale_curr = 1;
+        if (unlikely(!data))
+                return;
         sbale++;
         sbale->addr = data;
-        if (likely(data))
-                sbale->length = len;
+        sbale->length = len;
 }
 
 /**
@@ -232,7 +209,7 @@ static inline
 void zfcp_qdio_sbal_limit(struct zfcp_qdio *qdio,
                           struct zfcp_qdio_req *q_req, int max_sbals)
 {
-        int count = min(atomic_read(&qdio->req_q.count), max_sbals);
+        int count = min(atomic_read(&qdio->req_q_free), max_sbals);
 
         q_req->sbal_limit = (q_req->sbal_first + count - 1) %
                                 QDIO_MAX_BUFFERS_PER_Q;