IB/ehca: Allocate event queue size depending on max number of CQs and QPs

If a lot of QPs fall into Error state at once and the EQ of the
respective HCA is too small, it might overrun, causing the eHCA driver
to stop processing completion events and calling the application's
completion handlers, effectively causing traffic to stop.

Fix this by limiting available QPs and CQs to a customizable max
count, and determining EQ size based on these counts and a worst-case
assumption.

Signed-off-by: Stefan Roscher <stefan.roscher@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 34 insertions, 2 deletions

diff --git a/drivers/infiniband/hw/ehca/ehca_main.c b/drivers/infiniband/hw/ehca/ehca_main.c
index 65048976198..482103eb6ea 100644
--- a/drivers/infiniband/hw/ehca/ehca_main.c
+++ b/drivers/infiniband/hw/ehca/ehca_main.c
@@ -68,6 +68,8 @@ int ehca_port_act_time = 30;
 int ehca_static_rate   = -1;
 int ehca_scaling_code  = 0;
 int ehca_lock_hcalls   = -1;
+int ehca_max_cq        = -1;
+int ehca_max_qp        = -1;
 
 module_param_named(open_aqp1,     ehca_open_aqp1,     bool, S_IRUGO);
 module_param_named(debug_level,   ehca_debug_level,   int,  S_IRUGO);
@@ -79,6 +81,8 @@ module_param_named(poll_all_eqs,  ehca_poll_all_eqs,  bool, S_IRUGO);
 module_param_named(static_rate,   ehca_static_rate,   int,  S_IRUGO);
 module_param_named(scaling_code,  ehca_scaling_code,  bool, S_IRUGO);
 module_param_named(lock_hcalls,   ehca_lock_hcalls,   bool, S_IRUGO);
+module_param_named(number_of_cqs, ehca_max_cq,        int,  S_IRUGO);
+module_param_named(number_of_qps, ehca_max_qp,        int,  S_IRUGO);
 
 MODULE_PARM_DESC(open_aqp1,
 		 "Open AQP1 on startup (default: no)");
@@ -104,6 +108,12 @@ MODULE_PARM_DESC(scaling_code,
 MODULE_PARM_DESC(lock_hcalls,
 		 "Serialize all hCalls made by the driver "
 		 "(default: autodetect)");
+MODULE_PARM_DESC(number_of_cqs,
+		"Max number of CQs which can be allocated "
+		"(default: autodetect)");
+MODULE_PARM_DESC(number_of_qps,
+		"Max number of QPs which can be allocated "
+		"(default: autodetect)");
 
 DEFINE_RWLOCK(ehca_qp_idr_lock);
 DEFINE_RWLOCK(ehca_cq_idr_lock);
@@ -355,6 +365,25 @@ static int ehca_sense_attributes(struct ehca_shca *shca)
 		if (rblock->memory_page_size_supported & pgsize_map[i])
 			shca->hca_cap_mr_pgsize |= pgsize_map[i + 1];
 
+	/* Set maximum number of CQs and QPs to calculate EQ size */
+	if (ehca_max_qp == -1)
+		ehca_max_qp = min_t(int, rblock->max_qp, EHCA_MAX_NUM_QUEUES);
+	else if (ehca_max_qp < 1 || ehca_max_qp > rblock->max_qp) {
+		ehca_gen_err("Requested number of QPs is out of range (1 - %i) "
+			"specified by HW", rblock->max_qp);
+		ret = -EINVAL;
+		goto sense_attributes1;
+	}
+
+	if (ehca_max_cq == -1)
+		ehca_max_cq = min_t(int, rblock->max_cq, EHCA_MAX_NUM_QUEUES);
+	else if (ehca_max_cq < 1 || ehca_max_cq > rblock->max_cq) {
+		ehca_gen_err("Requested number of CQs is out of range (1 - %i) "
+			"specified by HW", rblock->max_cq);
+		ret = -EINVAL;
+		goto sense_attributes1;
+	}
+
 	/* query max MTU from first port -- it's the same for all ports */
 	port = (struct hipz_query_port *)rblock;
 	h_ret = hipz_h_query_port(shca->ipz_hca_handle, 1, port);
@@ -684,7 +713,7 @@ static int __devinit ehca_probe(struct of_device *dev,
 	struct ehca_shca *shca;
 	const u64 *handle;
 	struct ib_pd *ibpd;
-	int ret, i;
+	int ret, i, eq_size;
 
 	handle = of_get_property(dev->node, "ibm,hca-handle", NULL);
 	if (!handle) {
@@ -705,6 +734,8 @@ static int __devinit ehca_probe(struct of_device *dev,
 		return -ENOMEM;
 	}
 	mutex_init(&shca->modify_mutex);
+	atomic_set(&shca->num_cqs, 0);
+	atomic_set(&shca->num_qps, 0);
 	for (i = 0; i < ARRAY_SIZE(shca->sport); i++)
 		spin_lock_init(&shca->sport[i].mod_sqp_lock);
 
@@ -724,8 +755,9 @@ static int __devinit ehca_probe(struct of_device *dev,
 		goto probe1;
 	}
 
+	eq_size = 2 * ehca_max_cq + 4 * ehca_max_qp;
 	/* create event queues */
-	ret = ehca_create_eq(shca, &shca->eq, EHCA_EQ, 2048);
+	ret = ehca_create_eq(shca, &shca->eq, EHCA_EQ, eq_size);
 	if (ret) {
 		ehca_err(&shca->ib_device, "Cannot create EQ.");
 		goto probe1;