RDMA/srp: Make the channel count configurable per target

Increase the flexibility of the SRP initiator driver by making the channel
count configurable per target instead of only providing a kernel module
parameter for configuring the channel count.

Link: https://lore.kernel.org/r/20200525172212.14413-2-bvanassche@acm.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 00b4f88..22fa872 100644 (file)
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -3424,6 +3424,7 @@ enum {
        SRP_OPT_IP_DEST         = 1 << 16,
        SRP_OPT_TARGET_CAN_QUEUE= 1 << 17,
        SRP_OPT_MAX_IT_IU_SIZE  = 1 << 18,
+       SRP_OPT_CH_COUNT        = 1 << 19,
 };
 
 static unsigned int srp_opt_mandatory[] = {
@@ -3457,6 +3458,7 @@ static const match_table_t srp_opt_tokens = {
        { SRP_OPT_IP_SRC,               "src=%s"                },
        { SRP_OPT_IP_DEST,              "dest=%s"               },
        { SRP_OPT_MAX_IT_IU_SIZE,       "max_it_iu_size=%d"     },
+       { SRP_OPT_CH_COUNT,             "ch_count=%u",          },
        { SRP_OPT_ERR,                  NULL                    }
 };
 
@@ -3758,6 +3760,14 @@ static int srp_parse_options(struct net *net, const char *buf,
                        target->max_it_iu_size = token;
                        break;
 
+               case SRP_OPT_CH_COUNT:
+                       if (match_int(args, &token) || token < 1) {
+                               pr_warn("bad channel count %s\n", p);
+                               goto out;
+                       }
+                       target->ch_count = token;
+                       break;
+
                default:
                        pr_warn("unknown parameter or missing value '%s' in target creation request\n",
                                p);
@@ -3921,11 +3931,13 @@ static ssize_t srp_create_target(struct device *dev,
                goto out;
 
        ret = -ENOMEM;
-       target->ch_count = max_t(unsigned, num_online_nodes(),
-                                min(ch_count ? :
-                                    min(4 * num_online_nodes(),
-                                        ibdev->num_comp_vectors),
-                                    num_online_cpus()));
+       if (target->ch_count == 0)
+               target->ch_count =
+                       max_t(unsigned int, num_online_nodes(),
+                             min(ch_count ?:
+                                         min(4 * num_online_nodes(),
+                                             ibdev->num_comp_vectors),
+                                 num_online_cpus()));
        target->ch = kcalloc(target->ch_count, sizeof(*target->ch),
                             GFP_KERNEL);
        if (!target->ch)