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io_uring: make IORING_POLL_ADD and IORING_POLL_REMOVE deferrable 

If we defer these commands as part of a link, we have to make sure that
the SQE data has been read upfront. Integrate the poll add/remove into
the prep handling to make it safe for SQE reuse.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
alistair/sunxi64-5.5-dsi
Jens Axboe 2019-12-17 18:40:57 -07:00
parent ffbb8d6b76
commit 0969e783e3
1 changed files with 55 additions and 15 deletions
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70
fs/io_uring.c
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@ -289,7 +289,10 @@ struct io_ring_ctx {
*/
struct io_poll_iocb {
struct file *file;
struct wait_queue_head *head;
union {
struct wait_queue_head *head;
u64 addr;
};
__poll_t events;
bool done;
bool canceled;
@ -2490,24 +2493,40 @@ static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr)
return -ENOENT;
}
/*
* Find a running poll command that matches one specified in sqe->addr,
* and remove it if found.
*/
static int io_poll_remove(struct io_kiocb *req)
static int io_poll_remove_prep(struct io_kiocb *req)
{
const struct io_uring_sqe *sqe = req->sqe;
struct io_ring_ctx *ctx = req->ctx;
int ret;
if (req->flags & REQ_F_PREPPED)
return 0;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index ||
sqe->poll_events)
return -EINVAL;
req->poll.addr = READ_ONCE(sqe->addr);
req->flags |= REQ_F_PREPPED;
return 0;
}
/*
* Find a running poll command that matches one specified in sqe->addr,
* and remove it if found.
*/
static int io_poll_remove(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
u64 addr;
int ret;
ret = io_poll_remove_prep(req);
if (ret)
return ret;
addr = req->poll.addr;
spin_lock_irq(&ctx->completion_lock);
ret = io_poll_cancel(ctx, READ_ONCE(sqe->addr));
ret = io_poll_cancel(ctx, addr);
spin_unlock_irq(&ctx->completion_lock);
io_cqring_add_event(req, ret);
@ -2642,16 +2661,14 @@ static void io_poll_req_insert(struct io_kiocb *req)
hlist_add_head(&req->hash_node, list);
}
static int io_poll_add(struct io_kiocb *req, struct io_kiocb **nxt)
static int io_poll_add_prep(struct io_kiocb *req)
{
const struct io_uring_sqe *sqe = req->sqe;
struct io_poll_iocb *poll = &req->poll;
struct io_ring_ctx *ctx = req->ctx;
struct io_poll_table ipt;
bool cancel = false;
__poll_t mask;
u16 events;
if (req->flags & REQ_F_PREPPED)
return 0;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index)
@ -2659,9 +2676,26 @@ static int io_poll_add(struct io_kiocb *req, struct io_kiocb **nxt)
if (!poll->file)
return -EBADF;
INIT_IO_WORK(&req->work, io_poll_complete_work);
req->flags |= REQ_F_PREPPED;
events = READ_ONCE(sqe->poll_events);
poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;
return 0;
}
static int io_poll_add(struct io_kiocb *req, struct io_kiocb **nxt)
{
struct io_poll_iocb *poll = &req->poll;
struct io_ring_ctx *ctx = req->ctx;
struct io_poll_table ipt;
bool cancel = false;
__poll_t mask;
int ret;
ret = io_poll_add_prep(req);
if (ret)
return ret;
INIT_IO_WORK(&req->work, io_poll_complete_work);
INIT_HLIST_NODE(&req->hash_node);
poll->head = NULL;
@ -3029,6 +3063,12 @@ static int io_req_defer_prep(struct io_kiocb *req)
io_req_map_rw(req, ret, iovec, inline_vecs, &iter);
ret = 0;
break;
case IORING_OP_POLL_ADD:
ret = io_poll_add_prep(req);
break;
case IORING_OP_POLL_REMOVE:
ret = io_poll_remove_prep(req);
break;
case IORING_OP_FSYNC:
ret = io_prep_fsync(req);
break;