IB/iser: Maintain connection fmr_pool under a single registration descriptor

This will allow us to unify the memory registration code path between
the various methods which vary by the device capabilities. This change
will make it easier and less intrusive to remove fmr_pools from the
code when we'd want to.

The reason we use a single descriptor is to avoid taking a
redundant spinlock when working with FMRs.

We also change the signature of iser_reg_page_vec to make it match
iser_fast_reg_mr (and the future indirect registration method).

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Adir Lev <adirl@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/ulp/iser/iser_verbs.c

@@ -204,17 +204,25 @@ int iser_alloc_fmr_pool(struct ib_conn *ib_conn, unsigned cmds_max)
 	struct iser_device *device = ib_conn->device;
 	struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
 	struct iser_page_vec *page_vec;
+	struct iser_fr_desc *desc;
 	struct ib_fmr_pool *fmr_pool;
 	struct ib_fmr_pool_param params;
-	int ret = -ENOMEM;
+	int ret;
 
+	INIT_LIST_HEAD(&fr_pool->list);
 	spin_lock_init(&fr_pool->lock);
 
+	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+	if (!desc)
+		return -ENOMEM;
+
 	page_vec = kmalloc(sizeof(*page_vec) +
 			   (sizeof(u64) * (ISCSI_ISER_SG_TABLESIZE + 1)),
 			   GFP_KERNEL);
-	if (!page_vec)
-		return ret;
+	if (!page_vec) {
+		ret = -ENOMEM;
+		goto err_frpl;
+	}
 
 	page_vec->pages = (u64 *)(page_vec + 1);
 
@@ -236,16 +244,20 @@ int iser_alloc_fmr_pool(struct ib_conn *ib_conn, unsigned cmds_max)
 	if (IS_ERR(fmr_pool)) {
 		ret = PTR_ERR(fmr_pool);
 		iser_err("FMR allocation failed, err %d\n", ret);
-		goto err;
+		goto err_fmr;
 	}
 
-	fr_pool->fmr.page_vec = page_vec;
-	fr_pool->fmr.pool = fmr_pool;
+	desc->rsc.page_vec = page_vec;
+	desc->rsc.fmr_pool = fmr_pool;
+	list_add(&desc->list, &fr_pool->list);
 
 	return 0;
 
-err:
+err_fmr:
 	kfree(page_vec);
+err_frpl:
+	kfree(desc);
+
 	return ret;
 }
 
@@ -255,14 +267,18 @@ err:
 void iser_free_fmr_pool(struct ib_conn *ib_conn)
 {
 	struct iser_fr_pool *fr_pool = &ib_conn->fr_pool;
+	struct iser_fr_desc *desc;
+
+	desc = list_first_entry(&fr_pool->list,
+				struct iser_fr_desc, list);
+	list_del(&desc->list);
 
 	iser_info("freeing conn %p fmr pool %p\n",
-		  ib_conn, fr_pool->fmr.pool);
+		  ib_conn, desc->rsc.fmr_pool);
 
-	ib_destroy_fmr_pool(fr_pool->fmr.pool);
-	fr_pool->fmr.pool = NULL;
-	kfree(fr_pool->fmr.page_vec);
-	fr_pool->fmr.page_vec = NULL;
+	ib_destroy_fmr_pool(desc->rsc.fmr_pool);
+	kfree(desc->rsc.page_vec);
+	kfree(desc);
 }
 
 static int
@@ -392,9 +408,9 @@ int iser_alloc_fastreg_pool(struct ib_conn *ib_conn, unsigned cmds_max)
 	struct iser_fr_desc *desc;
 	int i, ret;
 
-	INIT_LIST_HEAD(&fr_pool->fastreg.pool);
+	INIT_LIST_HEAD(&fr_pool->list);
 	spin_lock_init(&fr_pool->lock);
-	fr_pool->fastreg.pool_size = 0;
+	fr_pool->size = 0;
 	for (i = 0; i < cmds_max; i++) {
 		desc = iser_create_fastreg_desc(device->ib_device, device->pd,
 						ib_conn->pi_support);
@@ -403,8 +419,8 @@ int iser_alloc_fastreg_pool(struct ib_conn *ib_conn, unsigned cmds_max)
 			goto err;
 		}
 
-		list_add_tail(&desc->list, &fr_pool->fastreg.pool);
-		fr_pool->fastreg.pool_size++;
+		list_add_tail(&desc->list, &fr_pool->list);
+		fr_pool->size++;
 	}
 
 	return 0;
@@ -423,12 +439,12 @@ void iser_free_fastreg_pool(struct ib_conn *ib_conn)
 	struct iser_fr_desc *desc, *tmp;
 	int i = 0;
 
-	if (list_empty(&fr_pool->fastreg.pool))
+	if (list_empty(&fr_pool->list))
 		return;
 
 	iser_info("freeing conn %p fr pool\n", ib_conn);
 
-	list_for_each_entry_safe(desc, tmp, &fr_pool->fastreg.pool, list) {
+	list_for_each_entry_safe(desc, tmp, &fr_pool->list, list) {
 		list_del(&desc->list);
 		iser_free_reg_res(&desc->rsc);
 		if (desc->pi_ctx)
@@ -437,9 +453,9 @@ void iser_free_fastreg_pool(struct ib_conn *ib_conn)
 		++i;
 	}
 
-	if (i < fr_pool->fastreg.pool_size)
+	if (i < fr_pool->size)
 		iser_warn("pool still has %d regions registered\n",
-			  fr_pool->fastreg.pool_size - i);
+			  fr_pool->size - i);
 }
 
 /**