From: Pavel Begunkov <[email protected]>
To: [email protected], [email protected]
Cc: Jens Axboe <[email protected]>, [email protected]
Subject: [PATCH 1/4] io_uring: don't derive close state from ->func
Date: Mon, 8 Jun 2020 21:08:17 +0300 [thread overview]
Message-ID: <8935dcfc447acd2ffd8b0397a21cf8cb0e6bdec4.1591637070.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>
Relying on having a specific work.func is dangerous, even if an opcode
handler set it itself. E.g. io_wq_assign_next() can modify it.
io_close() sets a custom work.func to indicate that
__close_fd_get_file() was already called. Fortunately, there is no bugs
with io_wq_assign_next() and close yet.
Still, do it safe and always be prepared to be called through
io_wq_submit_work(). Zero req->close.put_file in prep, and call
__close_fd_get_file() IFF it's NULL.
Signed-off-by: Pavel Begunkov <[email protected]>
---
fs/io_uring.c | 50 +++++++++++++++++---------------------------------
1 file changed, 17 insertions(+), 33 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 3aebbf96c123..9acd695cc473 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3479,53 +3479,37 @@ static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
req->close.fd == req->ctx->ring_fd)
return -EBADF;
+ req->close.put_file = NULL;
return 0;
}
-/* only called when __close_fd_get_file() is done */
-static void __io_close_finish(struct io_kiocb *req)
-{
- int ret;
-
- ret = filp_close(req->close.put_file, req->work.files);
- if (ret < 0)
- req_set_fail_links(req);
- io_cqring_add_event(req, ret);
- fput(req->close.put_file);
- io_put_req(req);
-}
-
-static void io_close_finish(struct io_wq_work **workptr)
-{
- struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work);
-
- /* not cancellable, don't do io_req_cancelled() */
- __io_close_finish(req);
- io_steal_work(req, workptr);
-}
-
static int io_close(struct io_kiocb *req, bool force_nonblock)
{
+ struct io_close *close = &req->close;
int ret;
- req->close.put_file = NULL;
- ret = __close_fd_get_file(req->close.fd, &req->close.put_file);
- if (ret < 0)
- return (ret == -ENOENT) ? -EBADF : ret;
+ /* might be already done during nonblock submission */
+ if (!close->put_file) {
+ ret = __close_fd_get_file(close->fd, &close->put_file);
+ if (ret < 0)
+ return (ret == -ENOENT) ? -EBADF : ret;
+ }
/* if the file has a flush method, be safe and punt to async */
- if (req->close.put_file->f_op->flush && force_nonblock) {
+ if (close->put_file->f_op->flush && force_nonblock) {
/* avoid grabbing files - we don't need the files */
req->flags |= REQ_F_NO_FILE_TABLE | REQ_F_MUST_PUNT;
- req->work.func = io_close_finish;
return -EAGAIN;
}
- /*
- * No ->flush(), safely close from here and just punt the
- * fput() to async context.
- */
- __io_close_finish(req);
+ /* No ->flush() or already async, safely close from here */
+ ret = filp_close(close->put_file, req->work.files);
+ if (ret < 0)
+ req_set_fail_links(req);
+ io_cqring_add_event(req, ret);
+ fput(close->put_file);
+ close->put_file = NULL;
+ io_put_req(req);
return 0;
}
--
2.24.0
next prev parent reply other threads:[~2020-06-08 18:09 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-08 18:08 [PATCH 0/4] remove work.func Pavel Begunkov
2020-06-08 18:08 ` Pavel Begunkov [this message]
2020-06-08 18:08 ` [PATCH 2/4] io_uring: remove custom ->func handlers Pavel Begunkov
2020-06-08 18:08 ` [PATCH 3/4] io_uring: don't arm a timeout through work.func Pavel Begunkov
2020-06-08 18:08 ` [PATCH 4/4] io_wq: add per-wq work handler instead of per work Pavel Begunkov
2020-06-08 18:14 ` [PATCH 0/4] remove work.func Pavel Begunkov
2020-06-08 20:00 ` Jens Axboe
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