target_core_alua: Allocate ALUA metadata on demand

We should only allocate ALUA metadata if we're actually going
to write them.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

3 files changed, 34 insertions, 42 deletions

diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c
index 292ecce98d1f..738244bceb1b 100644
--- a/drivers/target/target_core_alua.c
+++ b/drivers/target/target_core_alua.c
@@ -770,16 +770,22 @@ static int core_alua_write_tpg_metadata(
  */
 static int core_alua_update_tpg_primary_metadata(
         struct t10_alua_tg_pt_gp *tg_pt_gp,
-        int primary_state,
-        unsigned char *md_buf)
+        int primary_state)
 {
+        unsigned char *md_buf;
         struct t10_wwn *wwn = &tg_pt_gp->tg_pt_gp_dev->t10_wwn;
         char path[ALUA_METADATA_PATH_LEN];
-        int len;
+        int len, rc;
+
+        md_buf = kzalloc(ALUA_MD_BUF_LEN, GFP_KERNEL);
+        if (!md_buf) {
+                pr_err("Unable to allocate buf for ALUA metadata\n");
+                return -ENOMEM;
+        }
 
         memset(path, 0, ALUA_METADATA_PATH_LEN);
 
-        len = snprintf(md_buf, tg_pt_gp->tg_pt_gp_md_buf_len,
+        len = snprintf(md_buf, ALUA_MD_BUF_LEN,
                         "tg_pt_gp_id=%hu\n"
                         "alua_access_state=0x%02x\n"
                         "alua_access_status=0x%02x\n",
@@ -790,14 +796,15 @@ static int core_alua_update_tpg_primary_metadata(
                 "/var/target/alua/tpgs_%s/%s", &wwn->unit_serial[0],
                 config_item_name(&tg_pt_gp->tg_pt_gp_group.cg_item));
 
-        return core_alua_write_tpg_metadata(path, md_buf, len);
+        rc = core_alua_write_tpg_metadata(path, md_buf, len);
+        kfree(md_buf);
+        return rc;
 }
 
 static int core_alua_do_transition_tg_pt(
         struct t10_alua_tg_pt_gp *tg_pt_gp,
         struct se_port *l_port,
         struct se_node_acl *nacl,
-        unsigned char *md_buf,
         int new_state,
         int explicit)
 {
@@ -885,8 +892,7 @@ static int core_alua_do_transition_tg_pt(
          */
         if (tg_pt_gp->tg_pt_gp_write_metadata) {
                 mutex_lock(&tg_pt_gp->tg_pt_gp_md_mutex);
-                core_alua_update_tpg_primary_metadata(tg_pt_gp,
-                                        new_state, md_buf);
+                core_alua_update_tpg_primary_metadata(tg_pt_gp, new_state);
                 mutex_unlock(&tg_pt_gp->tg_pt_gp_md_mutex);
         }
         /*
@@ -917,19 +923,12 @@ int core_alua_do_port_transition(
         struct t10_alua_lu_gp *lu_gp;
         struct t10_alua_lu_gp_member *lu_gp_mem, *local_lu_gp_mem;
         struct t10_alua_tg_pt_gp *tg_pt_gp;
-        unsigned char *md_buf;
         int primary, valid_states;
 
         valid_states = l_tg_pt_gp->tg_pt_gp_alua_supported_states;
         if (core_alua_check_transition(new_state, valid_states, &primary) != 0)
                 return -EINVAL;
 
-        md_buf = kzalloc(l_tg_pt_gp->tg_pt_gp_md_buf_len, GFP_KERNEL);
-        if (!md_buf) {
-                pr_err("Unable to allocate buf for ALUA metadata\n");
-                return -ENOMEM;
-        }
-
         local_lu_gp_mem = l_dev->dev_alua_lu_gp_mem;
         spin_lock(&local_lu_gp_mem->lu_gp_mem_lock);
         lu_gp = local_lu_gp_mem->lu_gp;
@@ -947,10 +946,9 @@ int core_alua_do_port_transition(
                  * success.
                  */
                 core_alua_do_transition_tg_pt(l_tg_pt_gp, l_port, l_nacl,
-                                        md_buf, new_state, explicit);
+                                        new_state, explicit);
                 atomic_dec(&lu_gp->lu_gp_ref_cnt);
                 smp_mb__after_atomic_dec();
-                kfree(md_buf);
                 return 0;
         }
         /*
@@ -1000,7 +998,7 @@ int core_alua_do_port_transition(
                          * success.
                          */
                         core_alua_do_transition_tg_pt(tg_pt_gp, port,
-                                        nacl, md_buf, new_state, explicit);
+                                        nacl, new_state, explicit);
 
                         spin_lock(&dev->t10_alua.tg_pt_gps_lock);
                         atomic_dec(&tg_pt_gp->tg_pt_gp_ref_cnt);
@@ -1022,7 +1020,6 @@ int core_alua_do_port_transition(
 
         atomic_dec(&lu_gp->lu_gp_ref_cnt);
         smp_mb__after_atomic_dec();
-        kfree(md_buf);
         return 0;
 }
 
@@ -1031,13 +1028,18 @@ int core_alua_do_port_transition(
  */
 static int core_alua_update_tpg_secondary_metadata(
         struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem,
-        struct se_port *port,
-        unsigned char *md_buf,
-        u32 md_buf_len)
+        struct se_port *port)
 {
+        unsigned char *md_buf;
         struct se_portal_group *se_tpg = port->sep_tpg;
         char path[ALUA_METADATA_PATH_LEN], wwn[ALUA_SECONDARY_METADATA_WWN_LEN];
-        int len;
+        int len, rc;
+
+        md_buf = kzalloc(ALUA_MD_BUF_LEN, GFP_KERNEL);
+        if (!md_buf) {
+                pr_err("Unable to allocate buf for ALUA metadata\n");
+                return -ENOMEM;
+        }
 
         memset(path, 0, ALUA_METADATA_PATH_LEN);
         memset(wwn, 0, ALUA_SECONDARY_METADATA_WWN_LEN);
@@ -1049,7 +1051,7 @@ static int core_alua_update_tpg_secondary_metadata(
                 snprintf(wwn+len, ALUA_SECONDARY_METADATA_WWN_LEN-len, "+%hu",
                                 se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg));
 
-        len = snprintf(md_buf, md_buf_len, "alua_tg_pt_offline=%d\n"
+        len = snprintf(md_buf, ALUA_MD_BUF_LEN, "alua_tg_pt_offline=%d\n"
                         "alua_tg_pt_status=0x%02x\n",
                         atomic_read(&port->sep_tg_pt_secondary_offline),
                         port->sep_tg_pt_secondary_stat);
@@ -1058,7 +1060,10 @@ static int core_alua_update_tpg_secondary_metadata(
                         se_tpg->se_tpg_tfo->get_fabric_name(), wwn,
                         port->sep_lun->unpacked_lun);
 
-        return core_alua_write_tpg_metadata(path, md_buf, len);
+        rc = core_alua_write_tpg_metadata(path, md_buf, len);
+        kfree(md_buf);
+
+        return rc;
 }
 
 static int core_alua_set_tg_pt_secondary_state(
@@ -1068,8 +1073,6 @@ static int core_alua_set_tg_pt_secondary_state(
         int offline)
 {
         struct t10_alua_tg_pt_gp *tg_pt_gp;
-        unsigned char *md_buf;
-        u32 md_buf_len;
         int trans_delay_msecs;
 
         spin_lock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
@@ -1090,7 +1093,6 @@ static int core_alua_set_tg_pt_secondary_state(
         else
                 atomic_set(&port->sep_tg_pt_secondary_offline, 0);
 
-        md_buf_len = tg_pt_gp->tg_pt_gp_md_buf_len;
         port->sep_tg_pt_secondary_stat = (explicit) ?
                         ALUA_STATUS_ALTERED_BY_EXPLICIT_STPG :
                         ALUA_STATUS_ALTERED_BY_IMPLICIT_ALUA;
@@ -1112,18 +1114,9 @@ static int core_alua_set_tg_pt_secondary_state(
          * secondary state and status
          */
         if (port->sep_tg_pt_secondary_write_md) {
-                md_buf = kzalloc(md_buf_len, GFP_KERNEL);
-                if (!md_buf) {
-                        pr_err("Unable to allocate md_buf for"
-                                " secondary ALUA access metadata\n");
-                        return -ENOMEM;
-                }
                 mutex_lock(&port->sep_tg_pt_md_mutex);
-                core_alua_update_tpg_secondary_metadata(tg_pt_gp_mem, port,
-                                md_buf, md_buf_len);
+                core_alua_update_tpg_secondary_metadata(tg_pt_gp_mem, port);
                 mutex_unlock(&port->sep_tg_pt_md_mutex);
-
-                kfree(md_buf);
         }
 
         return 0;
@@ -1382,7 +1375,6 @@ struct t10_alua_tg_pt_gp *core_alua_allocate_tg_pt_gp(struct se_device *dev,
         spin_lock_init(&tg_pt_gp->tg_pt_gp_lock);
         atomic_set(&tg_pt_gp->tg_pt_gp_ref_cnt, 0);
         tg_pt_gp->tg_pt_gp_dev = dev;
-        tg_pt_gp->tg_pt_gp_md_buf_len = ALUA_MD_BUF_LEN;
         atomic_set(&tg_pt_gp->tg_pt_gp_alua_access_state,
                 ALUA_ACCESS_STATE_ACTIVE_OPTIMIZED);
         /*
diff --git a/drivers/target/target_core_alua.h b/drivers/target/target_core_alua.h
index 88e2e835f14a..1a152cd59471 100644
--- a/drivers/target/target_core_alua.h
+++ b/drivers/target/target_core_alua.h
@@ -78,6 +78,9 @@
  */
 #define ALUA_SECONDARY_METADATA_WWN_LEN                 256
 
+/* Used by core_alua_update_tpg_(primary,secondary)_metadata */
+#define ALUA_MD_BUF_LEN                                 1024
+
 extern struct kmem_cache *t10_alua_lu_gp_cache;
 extern struct kmem_cache *t10_alua_lu_gp_mem_cache;
 extern struct kmem_cache *t10_alua_tg_pt_gp_cache;
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index d6f96c735309..bf9a4d6c26da 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -291,9 +291,6 @@ struct t10_alua_tg_pt_gp {
         int     tg_pt_gp_implicit_trans_secs;
         int     tg_pt_gp_pref;
         int     tg_pt_gp_write_metadata;
-        /* Used by struct t10_alua_tg_pt_gp->tg_pt_gp_md_buf_len */
-#define ALUA_MD_BUF_LEN                         1024
-        u32     tg_pt_gp_md_buf_len;
         u32     tg_pt_gp_members;
         atomic_t tg_pt_gp_alua_access_state;
         atomic_t tg_pt_gp_ref_cnt;