[SCSI] zfcp: Fix request list handling in error path

Fix the handling of the request list in the error path:
 - Use irqsave for the lock as in the good path.
 - Before removing the request, check if it is still in the list, a
   call to dismiss_all might have changed the list in between.
 - zfcp_qdio_send does not change the queue counters on failure,
   trying revert something is wrong, so remove this.

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

diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
index 5e8517fc8b629e39c357313fa7d5e2c8ed05148c..d024442ee128d9ee04ec44c5fe6b43e9ec099959 100644 (file)
--- a/drivers/s390/scsi/zfcp_fsf.c
+++ b/drivers/s390/scsi/zfcp_fsf.c
@@ -770,7 +770,6 @@ static struct zfcp_fsf_req *zfcp_fsf_req_create(struct zfcp_adapter *adapter,
 static int zfcp_fsf_req_send(struct zfcp_fsf_req *req)
 {
        struct zfcp_adapter *adapter = req->adapter;
-       struct zfcp_qdio_queue *req_q = &adapter->req_q;
        unsigned long flags;
        int idx;
 
@@ -780,19 +779,15 @@ static int zfcp_fsf_req_send(struct zfcp_fsf_req *req)
        list_add_tail(&req->list, &adapter->req_list[idx]);
        spin_unlock_irqrestore(&adapter->req_list_lock, flags);
 
-       req->qdio_outb_usage = atomic_read(&req_q->count);
+       req->qdio_outb_usage = atomic_read(&adapter->req_q.count);
        req->issued = get_clock();
        if (zfcp_qdio_send(req)) {
-               /* Queues are down..... */
                del_timer(&req->timer);
-               spin_lock(&adapter->req_list_lock);
-               zfcp_reqlist_remove(adapter, req);
-               spin_unlock(&adapter->req_list_lock);
-               /* undo changes in request queue made for this request */
-               atomic_add(req->sbal_number, &req_q->count);
-               req_q->first -= req->sbal_number;
-               req_q->first += QDIO_MAX_BUFFERS_PER_Q;
-               req_q->first %= QDIO_MAX_BUFFERS_PER_Q; /* wrap */
+               spin_lock_irqsave(&adapter->req_list_lock, flags);
+               /* lookup request again, list might have changed */
+               if (zfcp_reqlist_find_safe(adapter, req))
+                       zfcp_reqlist_remove(adapter, req);
+               spin_unlock_irqrestore(&adapter->req_list_lock, flags);
                zfcp_erp_adapter_reopen(adapter, 0, 116, req);
                return -EIO;
        }