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authorTejun Heo <tj@kernel.org>2014-06-28 08:10:14 -0400
committerTejun Heo <tj@kernel.org>2014-06-28 08:10:14 -0400
commit9a1049da9bd2cd83fe11d46433e603c193aa9c71 (patch)
tree007d2843abf0f064c294659334e69e297ffc2b74 /fs/aio.c
parent7d742075120deb831c7b94c268ca20d409e91d60 (diff)
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 'fs/aio.c')
-rw-r--r--fs/aio.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 5e0d7f9cb693..ea1bc2e8f4f3 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -506,6 +506,8 @@ static void free_ioctx(struct work_struct *work)
506 506
507 aio_free_ring(ctx); 507 aio_free_ring(ctx);
508 free_percpu(ctx->cpu); 508 free_percpu(ctx->cpu);
509 percpu_ref_exit(&ctx->reqs);
510 percpu_ref_exit(&ctx->users);
509 kmem_cache_free(kioctx_cachep, ctx); 511 kmem_cache_free(kioctx_cachep, ctx);
510} 512}
511 513
@@ -715,8 +717,8 @@ err_ctx:
715err: 717err:
716 mutex_unlock(&ctx->ring_lock); 718 mutex_unlock(&ctx->ring_lock);
717 free_percpu(ctx->cpu); 719 free_percpu(ctx->cpu);
718 percpu_ref_cancel_init(&ctx->reqs); 720 percpu_ref_exit(&ctx->reqs);
719 percpu_ref_cancel_init(&ctx->users); 721 percpu_ref_exit(&ctx->users);
720 kmem_cache_free(kioctx_cachep, ctx); 722 kmem_cache_free(kioctx_cachep, ctx);
721 pr_debug("error allocating ioctx %d\n", err); 723 pr_debug("error allocating ioctx %d\n", err);
722 return ERR_PTR(err); 724 return ERR_PTR(err);