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authorTejun Heo <tj@kernel.org>2014-06-28 16:10:14 +0400
committerTejun Heo <tj@kernel.org>2014-06-28 16:10:14 +0400
commit9a1049da9bd2cd83fe11d46433e603c193aa9c71 (patch)
tree007d2843abf0f064c294659334e69e297ffc2b74 /drivers/target
parent7d742075120deb831c7b94c268ca20d409e91d60 (diff)
downloadlinux-9a1049da9bd2cd83fe11d46433e603c193aa9c71.tar.xz
percpu-refcount: require percpu_ref to be exited explicitly
Currently, a percpu_ref undoes percpu_ref_init() automatically by freeing the allocated percpu area when the percpu_ref is killed. While seemingly convenient, this has the following niggles. * It's impossible to re-init a released reference counter without going through re-allocation. * In the similar vein, it's impossible to initialize a percpu_ref count with static percpu variables. * We need and have an explicit destructor anyway for failure paths - percpu_ref_cancel_init(). This patch removes the automatic percpu counter freeing in percpu_ref_kill_rcu() and repurposes percpu_ref_cancel_init() into a generic destructor now named percpu_ref_exit(). percpu_ref_destroy() is considered but it gets confusing with percpu_ref_kill() while "exit" clearly indicates that it's the counterpart of percpu_ref_init(). All percpu_ref_cancel_init() users are updated to invoke percpu_ref_exit() instead and explicit percpu_ref_exit() calls are added to the destruction path of all percpu_ref users. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Benjamin LaHaise <bcrl@kvack.org> Cc: Kent Overstreet <kmo@daterainc.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Nicholas A. Bellinger <nab@linux-iscsi.org> Cc: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/target_core_tpg.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index c036595b17cf..fddfae61222f 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -825,7 +825,7 @@ int core_tpg_add_lun(
ret = core_dev_export(dev, tpg, lun);
if (ret < 0) {
- percpu_ref_cancel_init(&lun->lun_ref);
+ percpu_ref_exit(&lun->lun_ref);
return ret;
}
@@ -880,5 +880,7 @@ int core_tpg_post_dellun(
lun->lun_status = TRANSPORT_LUN_STATUS_FREE;
spin_unlock(&tpg->tpg_lun_lock);
+ percpu_ref_exit(&lun->lun_ref);
+
return 0;
}