IB/srpt: Introduce helper functions for SRQ allocation and freeing

The only functional change in this patch is in the srpt_add_one()
error path: if allocating the ring buffer for the SRQ fails, fall
back to non-SRQ mode instead of disabling SRP target functionality.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 72 insertions, 43 deletions

diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 98b1b80e476b..a5f232e9b1f3 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -2510,6 +2510,74 @@ static struct se_wwn *srpt_lookup_wwn(const char *name)
         return wwn;
 }
 
+static void srpt_free_srq(struct srpt_device *sdev)
+{
+        if (!sdev->srq)
+                return;
+
+        ib_destroy_srq(sdev->srq);
+        srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
+                             sdev->srq_size, srp_max_req_size, DMA_FROM_DEVICE);
+        sdev->srq = NULL;
+}
+
+static int srpt_alloc_srq(struct srpt_device *sdev)
+{
+        struct ib_srq_init_attr srq_attr = {
+                .event_handler = srpt_srq_event,
+                .srq_context = (void *)sdev,
+                .attr.max_wr = sdev->srq_size,
+                .attr.max_sge = 1,
+                .srq_type = IB_SRQT_BASIC,
+        };
+        struct ib_device *device = sdev->device;
+        struct ib_srq *srq;
+        int i;
+
+        WARN_ON_ONCE(sdev->srq);
+        srq = ib_create_srq(sdev->pd, &srq_attr);
+        if (IS_ERR(srq)) {
+                pr_debug("ib_create_srq() failed: %ld\n", PTR_ERR(srq));
+                return PTR_ERR(srq);
+        }
+
+        pr_debug("create SRQ #wr= %d max_allow=%d dev= %s\n", sdev->srq_size,
+                 sdev->device->attrs.max_srq_wr, device->name);
+
+        sdev->ioctx_ring = (struct srpt_recv_ioctx **)
+                srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
+                                      sizeof(*sdev->ioctx_ring[0]),
+                                      srp_max_req_size, DMA_FROM_DEVICE);
+        if (!sdev->ioctx_ring) {
+                ib_destroy_srq(srq);
+                return -ENOMEM;
+        }
+
+        sdev->use_srq = true;
+        sdev->srq = srq;
+
+        for (i = 0; i < sdev->srq_size; ++i)
+                srpt_post_recv(sdev, NULL, sdev->ioctx_ring[i]);
+
+        return 0;
+}
+
+static int srpt_use_srq(struct srpt_device *sdev, bool use_srq)
+{
+        struct ib_device *device = sdev->device;
+        int ret = 0;
+
+        if (!use_srq) {
+                srpt_free_srq(sdev);
+                sdev->use_srq = false;
+        } else if (use_srq && !sdev->srq) {
+                ret = srpt_alloc_srq(sdev);
+        }
+        pr_debug("%s(%s): use_srq = %d; ret = %d\n", __func__, device->name,
+                 sdev->use_srq, ret);
+        return ret;
+}
+
 /**
  * srpt_add_one() - Infiniband device addition callback function.
  */
@@ -2517,7 +2585,6 @@ static void srpt_add_one(struct ib_device *device)
 {
         struct srpt_device *sdev;
         struct srpt_port *sport;
-        struct ib_srq_init_attr srq_attr;
         int i;
 
         pr_debug("device = %p\n", device);
@@ -2539,38 +2606,7 @@ static void srpt_add_one(struct ib_device *device)
 
         sdev->srq_size = min(srpt_srq_size, sdev->device->attrs.max_srq_wr);
 
-        srq_attr.event_handler = srpt_srq_event;
-        srq_attr.srq_context = (void *)sdev;
-        srq_attr.attr.max_wr = sdev->srq_size;
-        srq_attr.attr.max_sge = 1;
-        srq_attr.attr.srq_limit = 0;
-        srq_attr.srq_type = IB_SRQT_BASIC;
-
-        sdev->srq = sdev->port[0].port_attrib.use_srq ?
-                ib_create_srq(sdev->pd, &srq_attr) : ERR_PTR(-ENOTSUPP);
-        if (IS_ERR(sdev->srq)) {
-                pr_debug("ib_create_srq() failed: %ld\n", PTR_ERR(sdev->srq));
-
-                /* SRQ not supported. */
-                sdev->use_srq = false;
-        } else {
-                pr_debug("create SRQ #wr= %d max_allow=%d dev= %s\n",
-                         sdev->srq_size, sdev->device->attrs.max_srq_wr,
-                         device->name);
-
-                sdev->use_srq = true;
-
-                sdev->ioctx_ring = (struct srpt_recv_ioctx **)
-                        srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
-                                              sizeof(*sdev->ioctx_ring[0]),
-                                              srp_max_req_size,
-                                              DMA_FROM_DEVICE);
-                if (!sdev->ioctx_ring)
-                        goto err_pd;
-
-                for (i = 0; i < sdev->srq_size; ++i)
-                        srpt_post_recv(sdev, NULL, sdev->ioctx_ring[i]);
-        }
+        srpt_use_srq(sdev, sdev->port[0].port_attrib.use_srq);
 
         if (!srpt_service_guid)
                 srpt_service_guid = be64_to_cpu(device->node_guid);
@@ -2630,12 +2666,7 @@ err_event:
 err_cm:
         ib_destroy_cm_id(sdev->cm_id);
 err_ring:
-        if (sdev->use_srq)
-                ib_destroy_srq(sdev->srq);
-        srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
-                             sdev->srq_size, srp_max_req_size,
-                             DMA_FROM_DEVICE);
-err_pd:
+        srpt_free_srq(sdev);
         ib_dealloc_pd(sdev->pd);
 free_dev:
         kfree(sdev);
@@ -2678,10 +2709,8 @@ static void srpt_remove_one(struct ib_device *device, void *client_data)
         spin_unlock(&srpt_dev_lock);
         srpt_release_sdev(sdev);
 
-        if (sdev->use_srq)
-                ib_destroy_srq(sdev->srq);
-        srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
-                             sdev->srq_size, srp_max_req_size, DMA_FROM_DEVICE);
+        srpt_free_srq(sdev);
+
         ib_dealloc_pd(sdev->pd);
 
         kfree(sdev);