target: Use array_zalloc for tpg_lun_list

Turns an order-10 allocation into slab-sized ones, thereby preventing
allocation failures with memory fragmentation.

This likely saves memory as well, as the slab allocator can pack objects
more tightly than the buddy allocator.

Signed-off-by: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

2 files changed, 38 insertions, 10 deletions

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 5cfaa4b6da4..fd7f17c303a 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -1429,7 +1429,7 @@ struct se_lun *core_get_lun_from_tpg(struct se_portal_group *tpg, u32 unpacked_l
                 spin_unlock(&tpg->tpg_lun_lock);
                 return NULL;
         }
-        lun = &tpg->tpg_lun_list[unpacked_lun];
+        lun = tpg->tpg_lun_list[unpacked_lun];
 
         if (lun->lun_status != TRANSPORT_LUN_STATUS_FREE) {
                 pr_err("%s Logical Unit Number: %u is not free on"
@@ -1462,7 +1462,7 @@ static struct se_lun *core_dev_get_lun(struct se_portal_group *tpg, u32 unpacked
                 spin_unlock(&tpg->tpg_lun_lock);
                 return NULL;
         }
-        lun = &tpg->tpg_lun_list[unpacked_lun];
+        lun = tpg->tpg_lun_list[unpacked_lun];
 
         if (lun->lun_status != TRANSPORT_LUN_STATUS_ACTIVE) {
                 pr_err("%s Logical Unit Number: %u is not active on"
diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index f3ea385737d..146fe47f11c 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -163,7 +163,7 @@ void core_tpg_add_node_to_devs(
 
         spin_lock(&tpg->tpg_lun_lock);
         for (i = 0; i < TRANSPORT_MAX_LUNS_PER_TPG; i++) {
-                lun = &tpg->tpg_lun_list[i];
+                lun = tpg->tpg_lun_list[i];
                 if (lun->lun_status != TRANSPORT_LUN_STATUS_ACTIVE)
                         continue;
 
@@ -222,6 +222,34 @@ static int core_set_queue_depth_for_node(
         return 0;
 }
 
+void array_free(void *array, int n)
+{
+        void **a = array;
+        int i;
+
+        for (i = 0; i < n; i++)
+                kfree(a[i]);
+        kfree(a);
+}
+
+static void *array_zalloc(int n, size_t size, gfp_t flags)
+{
+        void **a;
+        int i;
+
+        a = kzalloc(n * sizeof(void*), flags);
+        if (!a)
+                return NULL;
+        for (i = 0; i < n; i++) {
+                a[i] = kzalloc(size, flags);
+                if (!a[i]) {
+                        array_free(a, n);
+                        return NULL;
+                }
+        }
+        return a;
+}
+
 /*      core_create_device_list_for_node():
  *
  *
@@ -336,7 +364,7 @@ void core_tpg_clear_object_luns(struct se_portal_group *tpg)
 
         spin_lock(&tpg->tpg_lun_lock);
         for (i = 0; i < TRANSPORT_MAX_LUNS_PER_TPG; i++) {
-                lun = &tpg->tpg_lun_list[i];
+                lun = tpg->tpg_lun_list[i];
 
                 if ((lun->lun_status != TRANSPORT_LUN_STATUS_ACTIVE) ||
                     (lun->lun_se_dev == NULL))
@@ -661,8 +689,8 @@ int core_tpg_register(
         struct se_lun *lun;
         u32 i;
 
-        se_tpg->tpg_lun_list = kzalloc((sizeof(struct se_lun) *
-                                TRANSPORT_MAX_LUNS_PER_TPG), GFP_KERNEL);
+        se_tpg->tpg_lun_list = array_zalloc(TRANSPORT_MAX_LUNS_PER_TPG,
+                        sizeof(struct se_lun), GFP_KERNEL);
         if (!se_tpg->tpg_lun_list) {
                 pr_err("Unable to allocate struct se_portal_group->"
                                 "tpg_lun_list\n");
@@ -670,7 +698,7 @@ int core_tpg_register(
         }
 
         for (i = 0; i < TRANSPORT_MAX_LUNS_PER_TPG; i++) {
-                lun = &se_tpg->tpg_lun_list[i];
+                lun = se_tpg->tpg_lun_list[i];
                 lun->unpacked_lun = i;
                 lun->lun_status = TRANSPORT_LUN_STATUS_FREE;
                 atomic_set(&lun->lun_acl_count, 0);
@@ -756,7 +784,7 @@ int core_tpg_deregister(struct se_portal_group *se_tpg)
                 core_tpg_release_virtual_lun0(se_tpg);
 
         se_tpg->se_tpg_fabric_ptr = NULL;
-        kfree(se_tpg->tpg_lun_list);
+        array_free(se_tpg->tpg_lun_list, TRANSPORT_MAX_LUNS_PER_TPG);
         return 0;
 }
 EXPORT_SYMBOL(core_tpg_deregister);
@@ -777,7 +805,7 @@ struct se_lun *core_tpg_pre_addlun(
         }
 
         spin_lock(&tpg->tpg_lun_lock);
-        lun = &tpg->tpg_lun_list[unpacked_lun];
+        lun = tpg->tpg_lun_list[unpacked_lun];
         if (lun->lun_status == TRANSPORT_LUN_STATUS_ACTIVE) {
                 pr_err("TPG Logical Unit Number: %u is already active"
                         " on %s Target Portal Group: %u, ignoring request.\n",
@@ -835,7 +863,7 @@ struct se_lun *core_tpg_pre_dellun(
         }
 
         spin_lock(&tpg->tpg_lun_lock);
-        lun = &tpg->tpg_lun_list[unpacked_lun];
+        lun = tpg->tpg_lun_list[unpacked_lun];
         if (lun->lun_status != TRANSPORT_LUN_STATUS_ACTIVE) {
                 pr_err("%s Logical Unit Number: %u is not active on"
                         " Target Portal Group: %u, ignoring request.\n",