Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756270Ab3ENBYa (ORCPT ); Mon, 13 May 2013 21:24:30 -0400 Received: from mail-da0-f48.google.com ([209.85.210.48]:61272 "EHLO mail-da0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755766Ab3ENBTM (ORCPT ); Mon, 13 May 2013 21:19:12 -0400 From: Kent Overstreet To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-aio@kvack.org Cc: akpm@linux-foundation.org, Kent Overstreet , Zach Brown , Felipe Balbi , Greg Kroah-Hartman , Mark Fasheh , Joel Becker , Rusty Russell , Jens Axboe , Asai Thambi S P , Selvan Mani , Sam Bradshaw , Jeff Moyer , Al Viro , Benjamin LaHaise Subject: [PATCH 06/21] aio: io_cancel() no longer returns the io_event Date: Mon, 13 May 2013 18:18:43 -0700 Message-Id: <1368494338-7069-7-git-send-email-koverstreet@google.com> X-Mailer: git-send-email 1.8.2.1 In-Reply-To: <1368494338-7069-1-git-send-email-koverstreet@google.com> References: <1368494338-7069-1-git-send-email-koverstreet@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5901 Lines: 186 Originally, io_event() was documented to return the io_event if cancellation succeeded - the io_event wouldn't be delivered via the ring buffer like it normally would. But this isn't what the implementation was actually doing; the only driver implementing cancellation, the usb gadget code, never returned an io_event in its cancel function. And aio_complete() was recently changed to no longer suppress event delivery if the kiocb had been cancelled. This gets rid of the unused io_event argument to kiocb_cancel() and kiocb->ki_cancel(), and changes io_cancel() to return -EINPROGRESS if kiocb->ki_cancel() returned success. Also tweak the refcounting in kiocb_cancel() to make more sense. Signed-off-by: Kent Overstreet Cc: Zach Brown Cc: Felipe Balbi Cc: Greg Kroah-Hartman Cc: Mark Fasheh Cc: Joel Becker Cc: Rusty Russell Cc: Jens Axboe Cc: Asai Thambi S P Cc: Selvan Mani Cc: Sam Bradshaw Cc: Jeff Moyer Cc: Al Viro Cc: Benjamin LaHaise --- drivers/usb/gadget/inode.c | 3 +-- fs/aio.c | 40 ++++++++++------------------------------ include/linux/aio.h | 2 +- 3 files changed, 12 insertions(+), 33 deletions(-) diff --git a/drivers/usb/gadget/inode.c b/drivers/usb/gadget/inode.c index 570c005..e02c1e0 100644 --- a/drivers/usb/gadget/inode.c +++ b/drivers/usb/gadget/inode.c @@ -524,7 +524,7 @@ struct kiocb_priv { unsigned actual; }; -static int ep_aio_cancel(struct kiocb *iocb, struct io_event *e) +static int ep_aio_cancel(struct kiocb *iocb) { struct kiocb_priv *priv = iocb->private; struct ep_data *epdata; @@ -540,7 +540,6 @@ static int ep_aio_cancel(struct kiocb *iocb, struct io_event *e) // spin_unlock(&epdata->dev->lock); local_irq_enable(); - aio_put_req(iocb); return value; } diff --git a/fs/aio.c b/fs/aio.c index 93383b0..5e1b801 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -259,8 +259,7 @@ 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, - struct io_event *res) +static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb) { kiocb_cancel_fn *old, *cancel; int ret = -EINVAL; @@ -282,12 +281,10 @@ static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb, atomic_inc(&kiocb->ki_users); spin_unlock_irq(&ctx->ctx_lock); - memset(res, 0, sizeof(*res)); - res->obj = (u64)(unsigned long)kiocb->ki_obj.user; - res->data = kiocb->ki_user_data; - ret = cancel(kiocb, res); + ret = cancel(kiocb); spin_lock_irq(&ctx->ctx_lock); + aio_put_req(kiocb); return ret; } @@ -308,7 +305,6 @@ static void free_ioctx_rcu(struct rcu_head *head) static void free_ioctx(struct kioctx *ctx) { struct aio_ring *ring; - struct io_event res; struct kiocb *req; unsigned cpu, head, avail; @@ -319,7 +315,7 @@ static void free_ioctx(struct kioctx *ctx) struct kiocb, ki_list); list_del_init(&req->ki_list); - kiocb_cancel(ctx, req, &res); + kiocb_cancel(ctx, req); } spin_unlock_irq(&ctx->ctx_lock); @@ -709,21 +705,6 @@ void aio_complete(struct kiocb *iocb, long res, long res2) } /* - * cancelled requests don't get events, userland was given one - * when the event got cancelled. - */ - if (unlikely(xchg(&iocb->ki_cancel, - KIOCB_CANCELLED) == KIOCB_CANCELLED)) { - /* - * Can't use the percpu reqs_available here - could race with - * free_ioctx() - */ - atomic_inc(&ctx->reqs_available); - /* Still need the wake_up in case free_ioctx is waiting */ - goto put_rq; - } - - /* * Add a completion event to the ring buffer. Must be done holding * ctx->ctx_lock to prevent other code from messing with the tail * pointer since we might be called from irq context. @@ -775,7 +756,6 @@ void aio_complete(struct kiocb *iocb, long res, long res2) if (iocb->ki_eventfd != NULL) eventfd_signal(iocb->ki_eventfd, 1); -put_rq: /* everything turned out well, dispose of the aiocb. */ aio_put_req(iocb); @@ -1352,7 +1332,6 @@ static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, struct io_event __user *, result) { - struct io_event res; struct kioctx *ctx; struct kiocb *kiocb; u32 key; @@ -1370,18 +1349,19 @@ 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, &res); + ret = kiocb_cancel(ctx, kiocb); else ret = -EINVAL; spin_unlock_irq(&ctx->ctx_lock); if (!ret) { - /* Cancellation succeeded -- copy the result - * into the user's buffer. + /* + * The result argument is no longer used - the io_event is + * always delivered via the ring buffer. -EINPROGRESS indicates + * cancellation is progress: */ - if (copy_to_user(result, &res, sizeof(res))) - ret = -EFAULT; + ret = -EINPROGRESS; } put_ioctx(ctx); diff --git a/include/linux/aio.h b/include/linux/aio.h index 1bdf965..8c8dd1d 100644 --- a/include/linux/aio.h +++ b/include/linux/aio.h @@ -27,7 +27,7 @@ struct kiocb; */ #define KIOCB_CANCELLED ((void *) (~0ULL)) -typedef int (kiocb_cancel_fn)(struct kiocb *, struct io_event *); +typedef int (kiocb_cancel_fn)(struct kiocb *); struct kiocb { atomic_t ki_users; -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/