io_uring: find and cancel head link async work on files exit

Commit f254ac04c8 ("io_uring: enable lookup of links holding inflight files")
only handled 2 out of the three head link cases we have, we also need to
lookup and cancel work that is blocked in io-wq if that work has a link
that's holding a reference to the files structure.

Put the "cancel head links that hold this request pending" logic into
io_attempt_cancel(), which will to through the motions of finding and
canceling head links that hold the current inflight files stable request
pending.

Cc: stable@vger.kernel.org
Reported-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2020-08-16 08:23:05 -07:00
parent 9123e3a74e
commit b711d4eaf0

View File

@ -8063,6 +8063,33 @@ static bool io_timeout_remove_link(struct io_ring_ctx *ctx,
return found;
}
static bool io_cancel_link_cb(struct io_wq_work *work, void *data)
{
return io_match_link(container_of(work, struct io_kiocb, work), data);
}
static void io_attempt_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req)
{
enum io_wq_cancel cret;
/* cancel this particular work, if it's running */
cret = io_wq_cancel_work(ctx->io_wq, &req->work);
if (cret != IO_WQ_CANCEL_NOTFOUND)
return;
/* find links that hold this pending, cancel those */
cret = io_wq_cancel_cb(ctx->io_wq, io_cancel_link_cb, req, true);
if (cret != IO_WQ_CANCEL_NOTFOUND)
return;
/* if we have a poll link holding this pending, cancel that */
if (io_poll_remove_link(ctx, req))
return;
/* final option, timeout link is holding this req pending */
io_timeout_remove_link(ctx, req);
}
static void io_uring_cancel_files(struct io_ring_ctx *ctx,
struct files_struct *files)
{
@ -8116,10 +8143,8 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx,
continue;
}
} else {
io_wq_cancel_work(ctx->io_wq, &cancel_req->work);
/* could be a link, check and remove if it is */
if (!io_poll_remove_link(ctx, cancel_req))
io_timeout_remove_link(ctx, cancel_req);
/* cancel this request, or head link requests */
io_attempt_cancel(ctx, cancel_req);
io_put_req(cancel_req);
}