IB/srp: Make transport layer retry count configurable

Allow the InfiniBand RC retry count to be configured by the user as an
option in the target login string.  Reducing this retry count allows to
reduce the path failover time.

Signed-off-by: Vu Pham <vu@mellanox.com>
[ bvanassche: Rewrote patch description / changed default retry count ]

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: David Dillow <dillowda@ornl.gov>
Signed-off-by: Roland Dreier <roland@purestorage.com>

diff --git a/Documentation/ABI/stable/sysfs-driver-ib_srp b/Documentation/ABI/stable/sysfs-driver-ib_srp
index 5c53d28f775cde36f4e77f46e41dc9ead66aa9c1..18e9b279ebb14b07bc82a3428efbf8eccf7fe710 100644 (file)
--- a/Documentation/ABI/stable/sysfs-driver-ib_srp
+++ b/Documentation/ABI/stable/sysfs-driver-ib_srp
@@ -61,6 +61,8 @@ Description:  Interface for making ib_srp connect to a new target.
                  interrupt is handled by a different CPU then the comp_vector
                  parameter can be used to spread the SRP completion workload
                  over multiple CPU's.
+               * tl_retry_count, a number in the range 2..7 specifying the
+                 IB RC retry count.
 
 What:          /sys/class/infiniband_srp/srp-<hca>-<port_number>/ibdev
 Date:          January 2, 2006

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index f93baf8254c4d492065155b4b701529629260b30..11ebf3e7646a6bd6b808edfb8286289ad0f3db67 100644 (file)
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -390,7 +390,7 @@ static int srp_send_req(struct srp_target_port *target)
        req->param.responder_resources        = 4;
        req->param.remote_cm_response_timeout = 20;
        req->param.local_cm_response_timeout  = 20;
-       req->param.retry_count                = 7;
+       req->param.retry_count                = target->tl_retry_count;
        req->param.rnr_retry_count            = 7;
        req->param.max_cm_retries             = 15;
 
@@ -1907,6 +1907,14 @@ static ssize_t show_comp_vector(struct device *dev,
        return sprintf(buf, "%d\n", target->comp_vector);
 }
 
+static ssize_t show_tl_retry_count(struct device *dev,
+                                  struct device_attribute *attr, char *buf)
+{
+       struct srp_target_port *target = host_to_target(class_to_shost(dev));
+
+       return sprintf(buf, "%d\n", target->tl_retry_count);
+}
+
 static ssize_t show_cmd_sg_entries(struct device *dev,
                                   struct device_attribute *attr, char *buf)
 {
@@ -1934,6 +1942,7 @@ static DEVICE_ATTR(zero_req_lim,    S_IRUGO, show_zero_req_lim,      NULL);
 static DEVICE_ATTR(local_ib_port,   S_IRUGO, show_local_ib_port,   NULL);
 static DEVICE_ATTR(local_ib_device, S_IRUGO, show_local_ib_device, NULL);
 static DEVICE_ATTR(comp_vector,     S_IRUGO, show_comp_vector,     NULL);
+static DEVICE_ATTR(tl_retry_count,  S_IRUGO, show_tl_retry_count,  NULL);
 static DEVICE_ATTR(cmd_sg_entries,  S_IRUGO, show_cmd_sg_entries,  NULL);
 static DEVICE_ATTR(allow_ext_sg,    S_IRUGO, show_allow_ext_sg,    NULL);
 
@@ -1949,6 +1958,7 @@ static struct device_attribute *srp_host_attrs[] = {
        &dev_attr_local_ib_port,
        &dev_attr_local_ib_device,
        &dev_attr_comp_vector,
+       &dev_attr_tl_retry_count,
        &dev_attr_cmd_sg_entries,
        &dev_attr_allow_ext_sg,
        NULL
@@ -2073,6 +2083,7 @@ enum {
        SRP_OPT_ALLOW_EXT_SG    = 1 << 10,
        SRP_OPT_SG_TABLESIZE    = 1 << 11,
        SRP_OPT_COMP_VECTOR     = 1 << 12,
+       SRP_OPT_TL_RETRY_COUNT  = 1 << 13,
        SRP_OPT_ALL             = (SRP_OPT_ID_EXT       |
                                   SRP_OPT_IOC_GUID     |
                                   SRP_OPT_DGID         |
@@ -2094,6 +2105,7 @@ static const match_table_t srp_opt_tokens = {
        { SRP_OPT_ALLOW_EXT_SG,         "allow_ext_sg=%u"       },
        { SRP_OPT_SG_TABLESIZE,         "sg_tablesize=%u"       },
        { SRP_OPT_COMP_VECTOR,          "comp_vector=%u"        },
+       { SRP_OPT_TL_RETRY_COUNT,       "tl_retry_count=%u"     },
        { SRP_OPT_ERR,                  NULL                    }
 };
 
@@ -2257,6 +2269,15 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target)
                        target->comp_vector = token;
                        break;
 
+               case SRP_OPT_TL_RETRY_COUNT:
+                       if (match_int(args, &token) || token < 2 || token > 7) {
+                               pr_warn("bad tl_retry_count parameter '%s' (must be a number between 2 and 7)\n",
+                                       p);
+                               goto out;
+                       }
+                       target->tl_retry_count = token;
+                       break;
+
                default:
                        pr_warn("unknown parameter or missing value '%s' in target creation request\n",
                                p);
@@ -2311,6 +2332,7 @@ static ssize_t srp_create_target(struct device *dev,
        target->cmd_sg_cnt      = cmd_sg_entries;
        target->sg_tablesize    = indirect_sg_entries ? : cmd_sg_entries;
        target->allow_ext_sg    = allow_ext_sg;
+       target->tl_retry_count  = 7;
 
        ret = srp_parse_options(buf, target);
        if (ret)

diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index e641088c14dc37bda98e95134b4235f151e3c0fc..84d821b24ec72cdb240261b9a98e897d51bbbd4a 100644 (file)
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -157,6 +157,7 @@ struct srp_target_port {
        unsigned int            scsi_id;
        unsigned int            sg_tablesize;
        int                     comp_vector;
+       int                     tl_retry_count;
 
        struct ib_sa_path_rec   path;
        __be16                  orig_dgid[8];