IB/srp: Get rid of "Target has req_lim 0" messages

It's perfectly valid for a connection to an SRP target to have a
request limit of 0, so get rid of the message about it, which can spam
kernel logs even with printk_ratelimit().  Keep a count of such events
in a "zero_req_lim" SCSI host attribute instead, so someone who cares
can look at the statistics.

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

2 files changed, 17 insertions, 6 deletions

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 4ba790f54a24..f1401e1f2f97 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -894,12 +894,8 @@ static struct srp_iu *__srp_get_tx_iu(struct srp_target_port *target)
         if (target->tx_head - target->tx_tail >= SRP_SQ_SIZE)
                 return NULL;
 
-        if (unlikely(target->req_lim < 1)) {
-                if (printk_ratelimit())
-                        printk(KERN_DEBUG PFX "Target has req_lim %d\n",
-                               target->req_lim);
-                return NULL;
-        }
+        if (unlikely(target->req_lim < 1))
+                ++target->zero_req_lim;
 
         return target->tx_ring[target->tx_head & SRP_SQ_SIZE];
 }
@@ -1422,11 +1418,23 @@ static ssize_t show_dgid(struct class_device *cdev, char *buf)
                        be16_to_cpu(((__be16 *) target->path.dgid.raw)[7]));
 }
 
+static ssize_t show_zero_req_lim(struct class_device *cdev, char *buf)
+{
+        struct srp_target_port *target = host_to_target(class_to_shost(cdev));
+
+        if (target->state == SRP_TARGET_DEAD ||
+            target->state == SRP_TARGET_REMOVED)
+                return -ENODEV;
+
+        return sprintf(buf, "%d\n", target->zero_req_lim);
+}
+
 static CLASS_DEVICE_ATTR(id_ext,        S_IRUGO, show_id_ext,           NULL);
 static CLASS_DEVICE_ATTR(ioc_guid,      S_IRUGO, show_ioc_guid,         NULL);
 static CLASS_DEVICE_ATTR(service_id,    S_IRUGO, show_service_id,       NULL);
 static CLASS_DEVICE_ATTR(pkey,          S_IRUGO, show_pkey,             NULL);
 static CLASS_DEVICE_ATTR(dgid,          S_IRUGO, show_dgid,             NULL);
+static CLASS_DEVICE_ATTR(zero_req_lim,  S_IRUGO, show_zero_req_lim,     NULL);
 
 static struct class_device_attribute *srp_host_attrs[] = {
         &class_device_attr_id_ext,
@@ -1434,6 +1442,7 @@ static struct class_device_attribute *srp_host_attrs[] = {
         &class_device_attr_service_id,
         &class_device_attr_pkey,
         &class_device_attr_dgid,
+        &class_device_attr_zero_req_lim,
         NULL
 };
 
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index 033a44772ae3..ad45e4856e1c 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -138,6 +138,8 @@ struct srp_target_port {
         int                     max_ti_iu_len;
         s32                     req_lim;
 
+        int                     zero_req_lim;
+
         unsigned                rx_head;
         struct srp_iu          *rx_ring[SRP_RQ_SIZE];