Merge git://git.kvack.org/~bcrl/aio-next

Pull aio fix and cleanups from Ben LaHaise:
 "This consists of a couple of code cleanups plus a minor bug fix"

* git://git.kvack.org/~bcrl/aio-next:
  aio: cleanup: flatten kill_ioctx()
  aio: report error from io_destroy() when threads race in io_destroy()
  fs/aio.c: Remove ctx parameter in kiocb_cancel

1 files changed, 36 insertions, 34 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 56b28607c32d..4f078c054b41 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -477,7 +477,7 @@ void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel)
 }
 EXPORT_SYMBOL(kiocb_set_cancel_fn);
 
-static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb)
+static int kiocb_cancel(struct kiocb *kiocb)
 {
         kiocb_cancel_fn *old, *cancel;
 
@@ -538,7 +538,7 @@ static void free_ioctx_users(struct percpu_ref *ref)
                                        struct kiocb, ki_list);
 
                 list_del_init(&req->ki_list);
-                kiocb_cancel(ctx, req);
+                kiocb_cancel(req);
         }
 
         spin_unlock_irq(&ctx->ctx_lock);
@@ -727,42 +727,42 @@ err:
  *      when the processes owning a context have all exited to encourage
  *      the rapid destruction of the kioctx.
  */
-static void kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
+static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
                 struct completion *requests_done)
 {
-        if (!atomic_xchg(&ctx->dead, 1)) {
-                struct kioctx_table *table;
+        struct kioctx_table *table;
 
-                spin_lock(&mm->ioctx_lock);
-                rcu_read_lock();
-                table = rcu_dereference(mm->ioctx_table);
+        if (atomic_xchg(&ctx->dead, 1))
+                return -EINVAL;
 
-                WARN_ON(ctx != table->table[ctx->id]);
-                table->table[ctx->id] = NULL;
-                rcu_read_unlock();
-                spin_unlock(&mm->ioctx_lock);
 
-                /* percpu_ref_kill() will do the necessary call_rcu() */
-                wake_up_all(&ctx->wait);
+        spin_lock(&mm->ioctx_lock);
+        rcu_read_lock();
+        table = rcu_dereference(mm->ioctx_table);
 
-                /*
-                 * It'd be more correct to do this in free_ioctx(), after all
-                 * the outstanding kiocbs have finished - but by then io_destroy
-                 * has already returned, so io_setup() could potentially return
-                 * -EAGAIN with no ioctxs actually in use (as far as userspace
-                 *  could tell).
-                 */
-                aio_nr_sub(ctx->max_reqs);
+        WARN_ON(ctx != table->table[ctx->id]);
+        table->table[ctx->id] = NULL;
+        rcu_read_unlock();
+        spin_unlock(&mm->ioctx_lock);
 
-                if (ctx->mmap_size)
-                        vm_munmap(ctx->mmap_base, ctx->mmap_size);
+        /* percpu_ref_kill() will do the necessary call_rcu() */
+        wake_up_all(&ctx->wait);
 
-                ctx->requests_done = requests_done;
-                percpu_ref_kill(&ctx->users);
-        } else {
-                if (requests_done)
-                        complete(requests_done);
-        }
+        /*
+         * It'd be more correct to do this in free_ioctx(), after all
+         * the outstanding kiocbs have finished - but by then io_destroy
+         * has already returned, so io_setup() could potentially return
+         * -EAGAIN with no ioctxs actually in use (as far as userspace
+         *  could tell).
+         */
+        aio_nr_sub(ctx->max_reqs);
+
+        if (ctx->mmap_size)
+                vm_munmap(ctx->mmap_base, ctx->mmap_size);
+
+        ctx->requests_done = requests_done;
+        percpu_ref_kill(&ctx->users);
+        return 0;
 }
 
 /* wait_on_sync_kiocb:
@@ -1219,21 +1219,23 @@ SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
         if (likely(NULL != ioctx)) {
                 struct completion requests_done =
                         COMPLETION_INITIALIZER_ONSTACK(requests_done);
+                int ret;
 
                 /* Pass requests_done to kill_ioctx() where it can be set
                  * in a thread-safe way. If we try to set it here then we have
                  * a race condition if two io_destroy() called simultaneously.
                  */
-                kill_ioctx(current->mm, ioctx, &requests_done);
+                ret = kill_ioctx(current->mm, ioctx, &requests_done);
                 percpu_ref_put(&ioctx->users);
 
                 /* Wait until all IO for the context are done. Otherwise kernel
                  * keep using user-space buffers even if user thinks the context
                  * is destroyed.
                  */
-                wait_for_completion(&requests_done);
+                if (!ret)
+                        wait_for_completion(&requests_done);
 
-                return 0;
+                return ret;
         }
         pr_debug("EINVAL: io_destroy: invalid context id\n");
         return -EINVAL;
@@ -1595,7 +1597,7 @@ SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
 
         kiocb = lookup_kiocb(ctx, iocb, key);
         if (kiocb)
-                ret = kiocb_cancel(ctx, kiocb);
+                ret = kiocb_cancel(kiocb);
         else
                 ret = -EINVAL;