IB/ehca: Serialize hypervisor calls in ehca_register_mr()

Some pSeries hypervisor versions show a race condition in the allocate
MR hCall.  Serialize this call per adapter to circumvent this problem.

Signed-off-by: Joachim Fenkes <fenkes@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

3 files changed, 14 insertions, 2 deletions

diff --git a/drivers/infiniband/hw/ehca/ehca_classes.h b/drivers/infiniband/hw/ehca/ehca_classes.h
index f64d42b08674..1d286d3cc2d5 100644
--- a/drivers/infiniband/hw/ehca/ehca_classes.h
+++ b/drivers/infiniband/hw/ehca/ehca_classes.h
@@ -277,6 +277,7 @@ void ehca_cleanup_mrmw_cache(void);
 
 extern spinlock_t ehca_qp_idr_lock;
 extern spinlock_t ehca_cq_idr_lock;
+extern spinlock_t hcall_lock;
 extern struct idr ehca_qp_idr;
 extern struct idr ehca_cq_idr;
 
diff --git a/drivers/infiniband/hw/ehca/ehca_main.c b/drivers/infiniband/hw/ehca/ehca_main.c
index fe90e7454560..b917cc130e48 100644
--- a/drivers/infiniband/hw/ehca/ehca_main.c
+++ b/drivers/infiniband/hw/ehca/ehca_main.c
@@ -98,6 +98,7 @@ MODULE_PARM_DESC(scaling_code,
 
 spinlock_t ehca_qp_idr_lock;
 spinlock_t ehca_cq_idr_lock;
+spinlock_t hcall_lock;
 DEFINE_IDR(ehca_qp_idr);
 DEFINE_IDR(ehca_cq_idr);
 
@@ -817,6 +818,7 @@ int __init ehca_module_init(void)
         idr_init(&ehca_cq_idr);
         spin_lock_init(&ehca_qp_idr_lock);
         spin_lock_init(&ehca_cq_idr_lock);
+        spin_lock_init(&hcall_lock);
 
         INIT_LIST_HEAD(&shca_list);
         spin_lock_init(&shca_list_lock);
diff --git a/drivers/infiniband/hw/ehca/hcp_if.c b/drivers/infiniband/hw/ehca/hcp_if.c
index b564fcd3b282..7f0beec74f70 100644
--- a/drivers/infiniband/hw/ehca/hcp_if.c
+++ b/drivers/infiniband/hw/ehca/hcp_if.c
@@ -154,7 +154,8 @@ static long ehca_plpar_hcall9(unsigned long opcode,
                               unsigned long arg9)
 {
         long ret;
-        int i, sleep_msecs;
+        int i, sleep_msecs, lock_is_set = 0;
+        unsigned long flags;
 
         ehca_gen_dbg("opcode=%lx arg1=%lx arg2=%lx arg3=%lx arg4=%lx "
                      "arg5=%lx arg6=%lx arg7=%lx arg8=%lx arg9=%lx",
@@ -162,10 +163,18 @@ static long ehca_plpar_hcall9(unsigned long opcode,
                      arg8, arg9);
 
         for (i = 0; i < 5; i++) {
+                if ((opcode == H_ALLOC_RESOURCE) && (arg2 == 5)) {
+                        spin_lock_irqsave(&hcall_lock, flags);
+                        lock_is_set = 1;
+                }
+
                 ret = plpar_hcall9(opcode, outs,
                                    arg1, arg2, arg3, arg4, arg5,
                                    arg6, arg7, arg8, arg9);
 
+                if (lock_is_set)
+                        spin_unlock_irqrestore(&hcall_lock, flags);
+
                 if (H_IS_LONG_BUSY(ret)) {
                         sleep_msecs = get_longbusy_msecs(ret);
                         msleep_interruptible(sleep_msecs);
@@ -193,11 +202,11 @@ static long ehca_plpar_hcall9(unsigned long opcode,
                              opcode, ret, outs[0], outs[1], outs[2], outs[3],
                              outs[4], outs[5], outs[6], outs[7], outs[8]);
                 return ret;
-
         }
 
         return H_BUSY;
 }
+
 u64 hipz_h_alloc_resource_eq(const struct ipz_adapter_handle adapter_handle,
                              struct ehca_pfeq *pfeq,
                              const u32 neq_control,