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io_uring: keep all sqe->flags in req->flags

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It's a good idea to not read sqe->flags twice, as it's prone to security
bugs. Instead of passing it around, embeed them in req->flags. It's
already so except for IOSQE_IO_LINK.
1. rename former REQ_F_LINK -> REQ_F_LINK_HEAD
2. introduce and copy REQ_F_LINK, which mimics IO_IOSQE_LINK

And leave req_set_fail_links() using new REQ_F_LINK, because it's more
sensible.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2020-04-12 02:05:04 +03:00 committed by Jens Axboe
parent 1d4240cc9e
commit dea3b49c7f
1 changed files with 13 additions and 10 deletions
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23
fs/io_uring.c
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@ -508,6 +508,7 @@ enum {
REQ_F_FORCE_ASYNC_BIT = IOSQE_ASYNC_BIT,
REQ_F_BUFFER_SELECT_BIT = IOSQE_BUFFER_SELECT_BIT,
REQ_F_LINK_HEAD_BIT,
REQ_F_LINK_NEXT_BIT,
REQ_F_FAIL_LINK_BIT,
REQ_F_INFLIGHT_BIT,
@ -543,6 +544,8 @@ enum {
/* IOSQE_BUFFER_SELECT */
REQ_F_BUFFER_SELECT = BIT(REQ_F_BUFFER_SELECT_BIT),
/* head of a link */
REQ_F_LINK_HEAD = BIT(REQ_F_LINK_HEAD_BIT),
/* already grabbed next link */
REQ_F_LINK_NEXT = BIT(REQ_F_LINK_NEXT_BIT),
/* fail rest of links */
@ -1437,7 +1440,7 @@ static bool io_link_cancel_timeout(struct io_kiocb *req)
if (ret != -1) {
io_cqring_fill_event(req, -ECANCELED);
io_commit_cqring(ctx);
req->flags &= ~REQ_F_LINK;
req->flags &= ~REQ_F_LINK_HEAD;
io_put_req(req);
return true;
}
@ -1473,7 +1476,7 @@ static void io_req_link_next(struct io_kiocb *req, struct io_kiocb **nxtptr)
list_del_init(&req->link_list);
if (!list_empty(&nxt->link_list))
nxt->flags |= REQ_F_LINK;
nxt->flags |= REQ_F_LINK_HEAD;
*nxtptr = nxt;
break;
}
@ -1484,7 +1487,7 @@ static void io_req_link_next(struct io_kiocb *req, struct io_kiocb **nxtptr)
}
/*
* Called if REQ_F_LINK is set, and we fail the head request
* Called if REQ_F_LINK_HEAD is set, and we fail the head request
*/
static void io_fail_links(struct io_kiocb *req)
{
@ -1517,7 +1520,7 @@ static void io_fail_links(struct io_kiocb *req)
static void io_req_find_next(struct io_kiocb *req, struct io_kiocb **nxt)
{
if (likely(!(req->flags & REQ_F_LINK)))
if (likely(!(req->flags & REQ_F_LINK_HEAD)))
return;
/*
@ -1669,7 +1672,7 @@ static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
static inline bool io_req_multi_free(struct req_batch *rb, struct io_kiocb *req)
{
if ((req->flags & REQ_F_LINK) || io_is_fallback_req(req))
if ((req->flags & REQ_F_LINK_HEAD) || io_is_fallback_req(req))
return false;
if (!(req->flags & REQ_F_FIXED_FILE) || req->io)
@ -2562,7 +2565,7 @@ static int io_read(struct io_kiocb *req, bool force_nonblock)
req->result = 0;
io_size = ret;
if (req->flags & REQ_F_LINK)
if (req->flags & REQ_F_LINK_HEAD)
req->result = io_size;
/*
@ -2653,7 +2656,7 @@ static int io_write(struct io_kiocb *req, bool force_nonblock)
req->result = 0;
io_size = ret;
if (req->flags & REQ_F_LINK)
if (req->flags & REQ_F_LINK_HEAD)
req->result = io_size;
/*
@ -5476,7 +5479,7 @@ static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
{
struct io_kiocb *nxt;
if (!(req->flags & REQ_F_LINK))
if (!(req->flags & REQ_F_LINK_HEAD))
return NULL;
/* for polled retry, if flag is set, we already went through here */
if (req->flags & REQ_F_POLLED)
@ -5636,7 +5639,7 @@ static int io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
/* same numerical values with corresponding REQ_F_*, safe to copy */
req->flags |= sqe_flags & (IOSQE_IO_DRAIN | IOSQE_IO_HARDLINK |
IOSQE_ASYNC | IOSQE_FIXED_FILE |
IOSQE_BUFFER_SELECT);
IOSQE_BUFFER_SELECT | IOSQE_IO_LINK);
fd = READ_ONCE(sqe->fd);
ret = io_req_set_file(state, req, fd, sqe_flags);
@ -5687,7 +5690,7 @@ static int io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
req->ctx->drain_next = 0;
}
if (sqe_flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) {
req->flags |= REQ_F_LINK;
req->flags |= REQ_F_LINK_HEAD;
INIT_LIST_HEAD(&req->link_list);
if (io_alloc_async_ctx(req))