IB/hfi1: Add a safe wrapper for _rcd_get_by_index

hfi1_rcd_get_by_index assumes that the given index is in the correct
range.  In most cases this is correct because the index is bounded by
a loop.  For these cases, adding a range check to the function is
redundant.

For the use case that is not bounded by the loop range, a _safe wrapper
function is needed to validate the index before accessing the rcd array.

Add a _safe wrapper to _get_by_index to validate the index range.

Update appropriate call sites with the new _safe function.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/hfi1/init.c b/drivers/infiniband/hw/hfi1/init.c
index 04a383b8b0db..36c8a4ae8278 100644
--- a/drivers/infiniband/hw/hfi1/init.c
+++ b/drivers/infiniband/hw/hfi1/init.c
@@ -284,6 +284,27 @@ static int allocate_rcd_index(struct hfi1_devdata *dd,
 }
 
 /**
+ * hfi1_rcd_get_by_index_safe - validate the ctxt index before accessing the
+ * array
+ * @dd: pointer to a valid devdata structure
+ * @ctxt: the index of an possilbe rcd
+ *
+ * This is a wrapper for hfi1_rcd_get_by_index() to validate that the given
+ * ctxt index is valid.
+ *
+ * The caller is responsible for making the _put().
+ *
+ */
+struct hfi1_ctxtdata *hfi1_rcd_get_by_index_safe(struct hfi1_devdata *dd,
+						 u16 ctxt)
+{
+	if (ctxt < dd->num_rcv_contexts)
+		return hfi1_rcd_get_by_index(dd, ctxt);
+
+	return NULL;
+}
+
+/**
  * hfi1_rcd_get_by_index
  * @dd: pointer to a valid devdata structure
  * @ctxt: the index of an possilbe rcd