1 files changed, 10 insertions, 12 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 67e4b9047cc9..b9d64d89a043 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -228,12 +228,6 @@ static void __put_ioctx(struct kioctx *ctx)
         call_rcu(&ctx->rcu_head, ctx_rcu_free);
 }
 
-static inline void get_ioctx(struct kioctx *kioctx)
-{
-        BUG_ON(atomic_read(&kioctx->users) <= 0);
-        atomic_inc(&kioctx->users);
-}
-
 static inline int try_get_ioctx(struct kioctx *kioctx)
 {
         return atomic_inc_not_zero(&kioctx->users);
@@ -273,7 +267,7 @@ static struct kioctx *ioctx_alloc(unsigned nr_events)
         mm = ctx->mm = current->mm;
         atomic_inc(&mm->mm_count);
 
-        atomic_set(&ctx->users, 1);
+        atomic_set(&ctx->users, 2);
         spin_lock_init(&ctx->ctx_lock);
         spin_lock_init(&ctx->ring_info.ring_lock);
         init_waitqueue_head(&ctx->wait);
@@ -609,11 +603,16 @@ static void aio_fput_routine(struct work_struct *data)
                         fput(req->ki_filp);
 
                 /* Link the iocb into the context's free list */
+                rcu_read_lock();
                 spin_lock_irq(&ctx->ctx_lock);
                 really_put_req(ctx, req);
+                /*
+                 * at that point ctx might've been killed, but actual
+                 * freeing is RCU'd
+                 */
                 spin_unlock_irq(&ctx->ctx_lock);
+                rcu_read_unlock();
 
-                put_ioctx(ctx);
                 spin_lock_irq(&fput_lock);
         }
         spin_unlock_irq(&fput_lock);
@@ -644,7 +643,6 @@ static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
          * this function will be executed w/out any aio kthread wakeup.
          */
         if (unlikely(!fput_atomic(req->ki_filp))) {
-                get_ioctx(ctx);
                 spin_lock(&fput_lock);
                 list_add(&req->ki_list, &fput_head);
                 spin_unlock(&fput_lock);
@@ -1338,10 +1336,10 @@ SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
         ret = PTR_ERR(ioctx);
         if (!IS_ERR(ioctx)) {
                 ret = put_user(ioctx->user_id, ctxp);
-                if (!ret)
+                if (!ret) {
+                        put_ioctx(ioctx);
                         return 0;
-
-                get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */
+                }
                 io_destroy(ioctx);
         }