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SubjectRe: [PATCH resubmit 1/3] AIO: Move aio_cancel_all()
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On Tuesday 16 March 2010 17:46:10 Jeff Moyer wrote:
> Sergey Temerkhanov <temerkhanov@cifronik.ru> writes:
> > io_cancel() and aio_cancel_all() have inconsistent reference counting
> > (ki_users field of struct kiocb) which leads to unkillable processes upon
> > io_cancel() or io_destroy() syscalls. This patch fixes the undesired
> > behavior.
>
> Hi, Sergey,
>
> Thanks for the patch. Would you mind resubmitting it to make it a bit
> easier to review? The way you've done things, it is difficult to tell
> if you just moved the aio_cancel_all function or if you moved it and
> made changes. Please have the patch that moves it separated out from
> other changes, or at least mention in the changelog that the function
> was unchanged. Next, if you could tell what sorts of testing you've
> performed, that would be great. Finally, it would be a good idea to CC
> linux-aio@kvack.org on aio patches.
>
> Thanks!
> Jeff

Well, I've broken the 1st patch into 2. This one just moves aio_cancel_all()

Regards, Sergey Temerkhanov, Cifronic ZAO
diff -r b290b47c0880 fs/aio.c
--- a/fs/aio.c Tue Mar 16 13:51:13 2010 +0300
+++ b/fs/aio.c Tue Mar 16 18:55:59 2010 +0300
@@ -63,6 +63,8 @@
static void aio_kick_handler(struct work_struct *);
static void aio_queue_work(struct kioctx *);

+static void aio_cancel_all(struct kioctx *);
+
/* aio_setup
* Creates the slab caches used by the aio routines, panic on
* failure as this is done early during the boot sequence.
@@ -315,33 +317,6 @@
return ctx;
}

-/* aio_cancel_all
- * Cancels all outstanding aio requests on an aio context. Used
- * when the processes owning a context have all exited to encourage
- * the rapid destruction of the kioctx.
- */
-static void aio_cancel_all(struct kioctx *ctx)
-{
- int (*cancel)(struct kiocb *, struct io_event *);
- struct io_event res;
- spin_lock_irq(&ctx->ctx_lock);
- ctx->dead = 1;
- while (!list_empty(&ctx->active_reqs)) {
- struct list_head *pos = ctx->active_reqs.next;
- struct kiocb *iocb = list_kiocb(pos);
- list_del_init(&iocb->ki_list);
- cancel = iocb->ki_cancel;
- kiocbSetCancelled(iocb);
- if (cancel) {
- iocb->ki_users++;
- spin_unlock_irq(&ctx->ctx_lock);
- cancel(iocb, &res);
- spin_lock_irq(&ctx->ctx_lock);
- }
- }
- spin_unlock_irq(&ctx->ctx_lock);
-}
-
static void wait_for_all_aios(struct kioctx *ctx)
{
struct task_struct *tsk = current;
@@ -1038,6 +1013,33 @@
return ret;
}

+/* aio_cancel_all
+ * Cancels all outstanding aio requests on an aio context. Used
+ * when the processes owning a context have all exited to encourage
+ * the rapid destruction of the kioctx.
+ */
+static void aio_cancel_all(struct kioctx *ctx)
+{
+ int (*cancel)(struct kiocb *, struct io_event *);
+ struct io_event res;
+ spin_lock_irq(&ctx->ctx_lock);
+ ctx->dead = 1;
+ while (!list_empty(&ctx->active_reqs)) {
+ struct list_head *pos = ctx->active_reqs.next;
+ struct kiocb *iocb = list_kiocb(pos);
+ list_del_init(&iocb->ki_list);
+ cancel = iocb->ki_cancel;
+ kiocbSetCancelled(iocb);
+ if (cancel) {
+ iocb->ki_users++;
+ spin_unlock_irq(&ctx->ctx_lock);
+ cancel(iocb, &res);
+ spin_lock_irq(&ctx->ctx_lock);
+ }
+ }
+ spin_unlock_irq(&ctx->ctx_lock);
+}
+
/* aio_read_evt
* Pull an event off of the ioctx's event ring. Returns the number of
* events fetched (0 or 1 ;-)
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