IB: Add ib_modify_qp_is_ok() library function

The in-kernel mthca driver contains a table of which attributes are
valid for each queue pair state transition.  It turns out that both
other IB drivers -- ipath and ehca -- which are being prepared for
merging have copied this table, errors and all.

To forestall this code duplication, move this table and the code to
check parameters against it into a midlayer library function,
ib_modify_qp_is_ok().

Signed-off-by: Roland Dreier <rolandd@cisco.com>

2 files changed, 270 insertions, 0 deletions

diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
index 8e0ba16bcbd..ca07a2be87d 100644
--- a/drivers/infiniband/core/verbs.c
+++ b/drivers/infiniband/core/verbs.c
@@ -245,6 +245,258 @@ struct ib_qp *ib_create_qp(struct ib_pd *pd,
 }
 EXPORT_SYMBOL(ib_create_qp);
 
+static const struct {
+	int			valid;
+	enum ib_qp_attr_mask	req_param[IB_QPT_RAW_ETY + 1];
+	enum ib_qp_attr_mask	opt_param[IB_QPT_RAW_ETY + 1];
+} qp_state_table[IB_QPS_ERR + 1][IB_QPS_ERR + 1] = {
+	[IB_QPS_RESET] = {
+		[IB_QPS_RESET] = { .valid = 1 },
+		[IB_QPS_ERR]   = { .valid = 1 },
+		[IB_QPS_INIT]  = {
+			.valid = 1,
+			.req_param = {
+				[IB_QPT_UD]  = (IB_QP_PKEY_INDEX		|
+						IB_QP_PORT			|
+						IB_QP_QKEY),
+				[IB_QPT_UC]  = (IB_QP_PKEY_INDEX		|
+						IB_QP_PORT			|
+						IB_QP_ACCESS_FLAGS),
+				[IB_QPT_RC]  = (IB_QP_PKEY_INDEX		|
+						IB_QP_PORT			|
+						IB_QP_ACCESS_FLAGS),
+				[IB_QPT_SMI] = (IB_QP_PKEY_INDEX		|
+						IB_QP_QKEY),
+				[IB_QPT_GSI] = (IB_QP_PKEY_INDEX		|
+						IB_QP_QKEY),
+			}
+		},
+	},
+	[IB_QPS_INIT]  = {
+		[IB_QPS_RESET] = { .valid = 1 },
+		[IB_QPS_ERR] =   { .valid = 1 },
+		[IB_QPS_INIT]  = {
+			.valid = 1,
+			.opt_param = {
+				[IB_QPT_UD]  = (IB_QP_PKEY_INDEX		|
+						IB_QP_PORT			|
+						IB_QP_QKEY),
+				[IB_QPT_UC]  = (IB_QP_PKEY_INDEX		|
+						IB_QP_PORT			|
+						IB_QP_ACCESS_FLAGS),
+				[IB_QPT_RC]  = (IB_QP_PKEY_INDEX		|
+						IB_QP_PORT			|
+						IB_QP_ACCESS_FLAGS),
+				[IB_QPT_SMI] = (IB_QP_PKEY_INDEX		|
+						IB_QP_QKEY),
+				[IB_QPT_GSI] = (IB_QP_PKEY_INDEX		|
+						IB_QP_QKEY),
+			}
+		},
+		[IB_QPS_RTR]   = {
+			.valid = 1,
+			.req_param = {
+				[IB_QPT_UC]  = (IB_QP_AV			|
+						IB_QP_PATH_MTU			|
+						IB_QP_DEST_QPN			|
+						IB_QP_RQ_PSN),
+				[IB_QPT_RC]  = (IB_QP_AV			|
+						IB_QP_PATH_MTU			|
+						IB_QP_DEST_QPN			|
+						IB_QP_RQ_PSN			|
+						IB_QP_MAX_DEST_RD_ATOMIC	|
+						IB_QP_MIN_RNR_TIMER),
+			},
+			.opt_param = {
+				 [IB_QPT_UD]  = (IB_QP_PKEY_INDEX		|
+						 IB_QP_QKEY),
+				 [IB_QPT_UC]  = (IB_QP_ALT_PATH			|
+						 IB_QP_ACCESS_FLAGS		|
+						 IB_QP_PKEY_INDEX),
+				 [IB_QPT_RC]  = (IB_QP_ALT_PATH			|
+						 IB_QP_ACCESS_FLAGS		|
+						 IB_QP_PKEY_INDEX),
+				 [IB_QPT_SMI] = (IB_QP_PKEY_INDEX		|
+						 IB_QP_QKEY),
+				 [IB_QPT_GSI] = (IB_QP_PKEY_INDEX		|
+						 IB_QP_QKEY),
+			 }
+		}
+	},
+	[IB_QPS_RTR]   = {
+		[IB_QPS_RESET] = { .valid = 1 },
+		[IB_QPS_ERR] =   { .valid = 1 },
+		[IB_QPS_RTS]   = {
+			.valid = 1,
+			.req_param = {
+				[IB_QPT_UD]  = IB_QP_SQ_PSN,
+				[IB_QPT_UC]  = IB_QP_SQ_PSN,
+				[IB_QPT_RC]  = (IB_QP_TIMEOUT			|
+						IB_QP_RETRY_CNT			|
+						IB_QP_RNR_RETRY			|
+						IB_QP_SQ_PSN			|
+						IB_QP_MAX_QP_RD_ATOMIC),
+				[IB_QPT_SMI] = IB_QP_SQ_PSN,
+				[IB_QPT_GSI] = IB_QP_SQ_PSN,
+			},
+			.opt_param = {
+				 [IB_QPT_UD]  = (IB_QP_CUR_STATE		|
+						 IB_QP_QKEY),
+				 [IB_QPT_UC]  = (IB_QP_CUR_STATE		|
+						 IB_QP_ALT_PATH			|
+						 IB_QP_ACCESS_FLAGS		|
+						 IB_QP_PATH_MIG_STATE),
+				 [IB_QPT_RC]  = (IB_QP_CUR_STATE		|
+						 IB_QP_ALT_PATH			|
+						 IB_QP_ACCESS_FLAGS		|
+						 IB_QP_MIN_RNR_TIMER		|
+						 IB_QP_PATH_MIG_STATE),
+				 [IB_QPT_SMI] = (IB_QP_CUR_STATE		|
+						 IB_QP_QKEY),
+				 [IB_QPT_GSI] = (IB_QP_CUR_STATE		|
+						 IB_QP_QKEY),
+			 }
+		}
+	},
+	[IB_QPS_RTS]   = {
+		[IB_QPS_RESET] = { .valid = 1 },
+		[IB_QPS_ERR] =   { .valid = 1 },
+		[IB_QPS_RTS]   = {
+			.valid = 1,
+			.opt_param = {
+				[IB_QPT_UD]  = (IB_QP_CUR_STATE			|
+						IB_QP_QKEY),
+				[IB_QPT_UC]  = (IB_QP_ACCESS_FLAGS		|
+						IB_QP_ALT_PATH			|
+						IB_QP_PATH_MIG_STATE),
+				[IB_QPT_RC]  = (IB_QP_ACCESS_FLAGS		|
+						IB_QP_ALT_PATH			|
+						IB_QP_PATH_MIG_STATE		|
+						IB_QP_MIN_RNR_TIMER),
+				[IB_QPT_SMI] = (IB_QP_CUR_STATE			|
+						IB_QP_QKEY),
+				[IB_QPT_GSI] = (IB_QP_CUR_STATE			|
+						IB_QP_QKEY),
+			}
+		},
+		[IB_QPS_SQD]   = {
+			.valid = 1,
+			.opt_param = {
+				[IB_QPT_UD]  = IB_QP_EN_SQD_ASYNC_NOTIFY,
+				[IB_QPT_UC]  = IB_QP_EN_SQD_ASYNC_NOTIFY,
+				[IB_QPT_RC]  = IB_QP_EN_SQD_ASYNC_NOTIFY,
+				[IB_QPT_SMI] = IB_QP_EN_SQD_ASYNC_NOTIFY,
+				[IB_QPT_GSI] = IB_QP_EN_SQD_ASYNC_NOTIFY
+			}
+		},
+	},
+	[IB_QPS_SQD]   = {
+		[IB_QPS_RESET] = { .valid = 1 },
+		[IB_QPS_ERR] =   { .valid = 1 },
+		[IB_QPS_RTS]   = {
+			.valid = 1,
+			.opt_param = {
+				[IB_QPT_UD]  = (IB_QP_CUR_STATE			|
+						IB_QP_QKEY),
+				[IB_QPT_UC]  = (IB_QP_CUR_STATE			|
+						IB_QP_ALT_PATH			|
+						IB_QP_ACCESS_FLAGS		|
+						IB_QP_PATH_MIG_STATE),
+				[IB_QPT_RC]  = (IB_QP_CUR_STATE			|
+						IB_QP_ALT_PATH			|
+						IB_QP_ACCESS_FLAGS		|
+						IB_QP_MIN_RNR_TIMER		|
+						IB_QP_PATH_MIG_STATE),
+				[IB_QPT_SMI] = (IB_QP_CUR_STATE			|
+						IB_QP_QKEY),
+				[IB_QPT_GSI] = (IB_QP_CUR_STATE			|
+						IB_QP_QKEY),
+			}
+		},
+		[IB_QPS_SQD]   = {
+			.valid = 1,
+			.opt_param = {
+				[IB_QPT_UD]  = (IB_QP_PKEY_INDEX		|
+						IB_QP_QKEY),
+				[IB_QPT_UC]  = (IB_QP_AV			|
+						IB_QP_CUR_STATE			|
+						IB_QP_ALT_PATH			|
+						IB_QP_ACCESS_FLAGS		|
+						IB_QP_PKEY_INDEX		|
+						IB_QP_PATH_MIG_STATE),
+				[IB_QPT_RC]  = (IB_QP_PORT			|
+						IB_QP_AV			|
+						IB_QP_TIMEOUT			|
+						IB_QP_RETRY_CNT			|
+						IB_QP_RNR_RETRY			|
+						IB_QP_MAX_QP_RD_ATOMIC		|
+						IB_QP_MAX_DEST_RD_ATOMIC	|
+						IB_QP_CUR_STATE			|
+						IB_QP_ALT_PATH			|
+						IB_QP_ACCESS_FLAGS		|
+						IB_QP_PKEY_INDEX		|
+						IB_QP_MIN_RNR_TIMER		|
+						IB_QP_PATH_MIG_STATE),
+				[IB_QPT_SMI] = (IB_QP_PKEY_INDEX		|
+						IB_QP_QKEY),
+				[IB_QPT_GSI] = (IB_QP_PKEY_INDEX		|
+						IB_QP_QKEY),
+			}
+		}
+	},
+	[IB_QPS_SQE]   = {
+		[IB_QPS_RESET] = { .valid = 1 },
+		[IB_QPS_ERR] =   { .valid = 1 },
+		[IB_QPS_RTS]   = {
+			.valid = 1,
+			.opt_param = {
+				[IB_QPT_UD]  = (IB_QP_CUR_STATE			|
+						IB_QP_QKEY),
+				[IB_QPT_UC]  = (IB_QP_CUR_STATE			|
+						IB_QP_ACCESS_FLAGS),
+				[IB_QPT_SMI] = (IB_QP_CUR_STATE			|
+						IB_QP_QKEY),
+				[IB_QPT_GSI] = (IB_QP_CUR_STATE			|
+						IB_QP_QKEY),
+			}
+		}
+	},
+	[IB_QPS_ERR] = {
+		[IB_QPS_RESET] = { .valid = 1 },
+		[IB_QPS_ERR] =   { .valid = 1 }
+	}
+};
+
+int ib_modify_qp_is_ok(enum ib_qp_state cur_state, enum ib_qp_state next_state,
+		       enum ib_qp_type type, enum ib_qp_attr_mask mask)
+{
+	enum ib_qp_attr_mask req_param, opt_param;
+
+	if (cur_state  < 0 || cur_state  > IB_QPS_ERR ||
+	    next_state < 0 || next_state > IB_QPS_ERR)
+		return 0;
+
+	if (mask & IB_QP_CUR_STATE  &&
+	    cur_state != IB_QPS_RTR && cur_state != IB_QPS_RTS &&
+	    cur_state != IB_QPS_SQD && cur_state != IB_QPS_SQE)
+		return 0;
+
+	if (!qp_state_table[cur_state][next_state].valid)
+		return 0;
+
+	req_param = qp_state_table[cur_state][next_state].req_param[type];
+	opt_param = qp_state_table[cur_state][next_state].opt_param[type];
+
+	if ((mask & req_param) != req_param)
+		return 0;
+
+	if (mask & ~(req_param | opt_param | IB_QP_STATE))
+		return 0;
+
+	return 1;
+}
+EXPORT_SYMBOL(ib_modify_qp_is_ok);
+
 int ib_modify_qp(struct ib_qp *qp,
 		 struct ib_qp_attr *qp_attr,
 		 int qp_attr_mask)
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 61a4390ae9d..010287c844e 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -990,6 +990,24 @@ static inline int ib_copy_to_udata(struct ib_udata *udata, void *src, size_t len
 	return copy_to_user(udata->outbuf, src, len) ? -EFAULT : 0;
 }
 
+/**
+ * ib_modify_qp_is_ok - Check that the supplied attribute mask
+ * contains all required attributes and no attributes not allowed for
+ * the given QP state transition.
+ * @cur_state: Current QP state
+ * @next_state: Next QP state
+ * @type: QP type
+ * @mask: Mask of supplied QP attributes
+ *
+ * This function is a helper function that a low-level driver's
+ * modify_qp method can use to validate the consumer's input.  It
+ * checks that cur_state and next_state are valid QP states, that a
+ * transition from cur_state to next_state is allowed by the IB spec,
+ * and that the attribute mask supplied is allowed for the transition.
+ */
+int ib_modify_qp_is_ok(enum ib_qp_state cur_state, enum ib_qp_state next_state,
+		       enum ib_qp_type type, enum ib_qp_attr_mask mask);
+
 int ib_register_event_handler  (struct ib_event_handler *event_handler);
 int ib_unregister_event_handler(struct ib_event_handler *event_handler);
 void ib_dispatch_event(struct ib_event *event);