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path: root/drivers/target/target_core_alua.c
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Diffstat (limited to 'drivers/target/target_core_alua.c')
-rw-r--r--drivers/target/target_core_alua.c83
1 files changed, 49 insertions, 34 deletions
diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c
index cb1de1ecaaa6..b56ef8af66e7 100644
--- a/drivers/target/target_core_alua.c
+++ b/drivers/target/target_core_alua.c
@@ -247,11 +247,11 @@ target_emulate_report_target_port_groups(struct se_cmd *cmd)
* this CDB was received upon to determine this value individually
* for ALUA target port group.
*/
- spin_lock(&cmd->se_lun->lun_tg_pt_gp_lock);
- tg_pt_gp = cmd->se_lun->lun_tg_pt_gp;
+ rcu_read_lock();
+ tg_pt_gp = rcu_dereference(cmd->se_lun->lun_tg_pt_gp);
if (tg_pt_gp)
buf[5] = tg_pt_gp->tg_pt_gp_implicit_trans_secs;
- spin_unlock(&cmd->se_lun->lun_tg_pt_gp_lock);
+ rcu_read_unlock();
}
transport_kunmap_data_sg(cmd);
@@ -292,24 +292,24 @@ target_emulate_set_target_port_groups(struct se_cmd *cmd)
* Determine if explicit ALUA via SET_TARGET_PORT_GROUPS is allowed
* for the local tg_pt_gp.
*/
- spin_lock(&l_lun->lun_tg_pt_gp_lock);
- l_tg_pt_gp = l_lun->lun_tg_pt_gp;
+ rcu_read_lock();
+ l_tg_pt_gp = rcu_dereference(l_lun->lun_tg_pt_gp);
if (!l_tg_pt_gp) {
- spin_unlock(&l_lun->lun_tg_pt_gp_lock);
+ rcu_read_unlock();
pr_err("Unable to access l_lun->tg_pt_gp\n");
rc = TCM_UNSUPPORTED_SCSI_OPCODE;
goto out;
}
if (!(l_tg_pt_gp->tg_pt_gp_alua_access_type & TPGS_EXPLICIT_ALUA)) {
- spin_unlock(&l_lun->lun_tg_pt_gp_lock);
+ rcu_read_unlock();
pr_debug("Unable to process SET_TARGET_PORT_GROUPS"
" while TPGS_EXPLICIT_ALUA is disabled\n");
rc = TCM_UNSUPPORTED_SCSI_OPCODE;
goto out;
}
valid_states = l_tg_pt_gp->tg_pt_gp_alua_supported_states;
- spin_unlock(&l_lun->lun_tg_pt_gp_lock);
+ rcu_read_unlock();
ptr = &buf[4]; /* Skip over RESERVED area in header */
@@ -662,17 +662,17 @@ target_alua_state_check(struct se_cmd *cmd)
" target port\n");
return TCM_ALUA_OFFLINE;
}
-
- if (!lun->lun_tg_pt_gp)
+ rcu_read_lock();
+ tg_pt_gp = rcu_dereference(lun->lun_tg_pt_gp);
+ if (!tg_pt_gp) {
+ rcu_read_unlock();
return 0;
+ }
- spin_lock(&lun->lun_tg_pt_gp_lock);
- tg_pt_gp = lun->lun_tg_pt_gp;
out_alua_state = tg_pt_gp->tg_pt_gp_alua_access_state;
nonop_delay_msecs = tg_pt_gp->tg_pt_gp_nonop_delay_msecs;
tg_pt_gp_id = tg_pt_gp->tg_pt_gp_id;
-
- spin_unlock(&lun->lun_tg_pt_gp_lock);
+ rcu_read_unlock();
/*
* Process ALUA_ACCESS_STATE_ACTIVE_OPTIMIZED in a separate conditional
* statement so the compiler knows explicitly to check this case first.
@@ -1219,10 +1219,10 @@ static int core_alua_set_tg_pt_secondary_state(
struct t10_alua_tg_pt_gp *tg_pt_gp;
int trans_delay_msecs;
- spin_lock(&lun->lun_tg_pt_gp_lock);
- tg_pt_gp = lun->lun_tg_pt_gp;
+ rcu_read_lock();
+ tg_pt_gp = rcu_dereference(lun->lun_tg_pt_gp);
if (!tg_pt_gp) {
- spin_unlock(&lun->lun_tg_pt_gp_lock);
+ rcu_read_unlock();
pr_err("Unable to complete secondary state"
" transition\n");
return -EINVAL;
@@ -1246,7 +1246,7 @@ static int core_alua_set_tg_pt_secondary_state(
"implicit", config_item_name(&tg_pt_gp->tg_pt_gp_group.cg_item),
tg_pt_gp->tg_pt_gp_id, (offline) ? "OFFLINE" : "ONLINE");
- spin_unlock(&lun->lun_tg_pt_gp_lock);
+ rcu_read_unlock();
/*
* Do the optional transition delay after we set the secondary
* ALUA access state.
@@ -1674,7 +1674,6 @@ int core_alua_set_tg_pt_gp_id(
pr_err("Maximum ALUA alua_tg_pt_gps_count:"
" 0x0000ffff reached\n");
spin_unlock(&dev->t10_alua.tg_pt_gps_lock);
- kmem_cache_free(t10_alua_tg_pt_gp_cache, tg_pt_gp);
return -ENOSPC;
}
again:
@@ -1755,13 +1754,14 @@ void core_alua_free_tg_pt_gp(
__target_attach_tg_pt_gp(lun,
dev->t10_alua.default_tg_pt_gp);
} else
- lun->lun_tg_pt_gp = NULL;
+ rcu_assign_pointer(lun->lun_tg_pt_gp, NULL);
spin_unlock(&lun->lun_tg_pt_gp_lock);
spin_lock(&tg_pt_gp->tg_pt_gp_lock);
}
spin_unlock(&tg_pt_gp->tg_pt_gp_lock);
+ synchronize_rcu();
kmem_cache_free(t10_alua_tg_pt_gp_cache, tg_pt_gp);
}
@@ -1806,7 +1806,7 @@ static void __target_attach_tg_pt_gp(struct se_lun *lun,
assert_spin_locked(&lun->lun_tg_pt_gp_lock);
spin_lock(&tg_pt_gp->tg_pt_gp_lock);
- lun->lun_tg_pt_gp = tg_pt_gp;
+ rcu_assign_pointer(lun->lun_tg_pt_gp, tg_pt_gp);
list_add_tail(&lun->lun_tg_pt_gp_link, &tg_pt_gp->tg_pt_gp_lun_list);
tg_pt_gp->tg_pt_gp_members++;
spin_lock(&lun->lun_deve_lock);
@@ -1823,6 +1823,7 @@ void target_attach_tg_pt_gp(struct se_lun *lun,
spin_lock(&lun->lun_tg_pt_gp_lock);
__target_attach_tg_pt_gp(lun, tg_pt_gp);
spin_unlock(&lun->lun_tg_pt_gp_lock);
+ synchronize_rcu();
}
static void __target_detach_tg_pt_gp(struct se_lun *lun,
@@ -1834,8 +1835,6 @@ static void __target_detach_tg_pt_gp(struct se_lun *lun,
list_del_init(&lun->lun_tg_pt_gp_link);
tg_pt_gp->tg_pt_gp_members--;
spin_unlock(&tg_pt_gp->tg_pt_gp_lock);
-
- lun->lun_tg_pt_gp = NULL;
}
void target_detach_tg_pt_gp(struct se_lun *lun)
@@ -1843,10 +1842,25 @@ void target_detach_tg_pt_gp(struct se_lun *lun)
struct t10_alua_tg_pt_gp *tg_pt_gp;
spin_lock(&lun->lun_tg_pt_gp_lock);
- tg_pt_gp = lun->lun_tg_pt_gp;
- if (tg_pt_gp)
+ tg_pt_gp = rcu_dereference_check(lun->lun_tg_pt_gp,
+ lockdep_is_held(&lun->lun_tg_pt_gp_lock));
+ if (tg_pt_gp) {
__target_detach_tg_pt_gp(lun, tg_pt_gp);
+ rcu_assign_pointer(lun->lun_tg_pt_gp, NULL);
+ }
spin_unlock(&lun->lun_tg_pt_gp_lock);
+ synchronize_rcu();
+}
+
+static void target_swap_tg_pt_gp(struct se_lun *lun,
+ struct t10_alua_tg_pt_gp *old_tg_pt_gp,
+ struct t10_alua_tg_pt_gp *new_tg_pt_gp)
+{
+ assert_spin_locked(&lun->lun_tg_pt_gp_lock);
+
+ if (old_tg_pt_gp)
+ __target_detach_tg_pt_gp(lun, old_tg_pt_gp);
+ __target_attach_tg_pt_gp(lun, new_tg_pt_gp);
}
ssize_t core_alua_show_tg_pt_gp_info(struct se_lun *lun, char *page)
@@ -1855,8 +1869,8 @@ ssize_t core_alua_show_tg_pt_gp_info(struct se_lun *lun, char *page)
struct t10_alua_tg_pt_gp *tg_pt_gp;
ssize_t len = 0;
- spin_lock(&lun->lun_tg_pt_gp_lock);
- tg_pt_gp = lun->lun_tg_pt_gp;
+ rcu_read_lock();
+ tg_pt_gp = rcu_dereference(lun->lun_tg_pt_gp);
if (tg_pt_gp) {
tg_pt_ci = &tg_pt_gp->tg_pt_gp_group.cg_item;
len += sprintf(page, "TG Port Alias: %s\nTG Port Group ID:"
@@ -1872,7 +1886,7 @@ ssize_t core_alua_show_tg_pt_gp_info(struct se_lun *lun, char *page)
"Offline" : "None",
core_alua_dump_status(lun->lun_tg_pt_secondary_stat));
}
- spin_unlock(&lun->lun_tg_pt_gp_lock);
+ rcu_read_unlock();
return len;
}
@@ -1919,7 +1933,8 @@ ssize_t core_alua_store_tg_pt_gp_info(
}
spin_lock(&lun->lun_tg_pt_gp_lock);
- tg_pt_gp = lun->lun_tg_pt_gp;
+ tg_pt_gp = rcu_dereference_check(lun->lun_tg_pt_gp,
+ lockdep_is_held(&lun->lun_tg_pt_gp_lock));
if (tg_pt_gp) {
/*
* Clearing an existing tg_pt_gp association, and replacing
@@ -1937,18 +1952,16 @@ ssize_t core_alua_store_tg_pt_gp_info(
&tg_pt_gp->tg_pt_gp_group.cg_item),
tg_pt_gp->tg_pt_gp_id);
- __target_detach_tg_pt_gp(lun, tg_pt_gp);
- __target_attach_tg_pt_gp(lun,
+ target_swap_tg_pt_gp(lun, tg_pt_gp,
dev->t10_alua.default_tg_pt_gp);
spin_unlock(&lun->lun_tg_pt_gp_lock);
- return count;
+ goto sync_rcu;
}
- __target_detach_tg_pt_gp(lun, tg_pt_gp);
move = 1;
}
- __target_attach_tg_pt_gp(lun, tg_pt_gp_new);
+ target_swap_tg_pt_gp(lun, tg_pt_gp, tg_pt_gp_new);
spin_unlock(&lun->lun_tg_pt_gp_lock);
pr_debug("Target_Core_ConfigFS: %s %s/tpgt_%hu/%s to ALUA"
" Target Port Group: alua/%s, ID: %hu\n", (move) ?
@@ -1959,6 +1972,8 @@ ssize_t core_alua_store_tg_pt_gp_info(
tg_pt_gp_new->tg_pt_gp_id);
core_alua_put_tg_pt_gp_from_name(tg_pt_gp_new);
+sync_rcu:
+ synchronize_rcu();
return count;
}
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