diff options
| -rw-r--r-- | io_uring/io_uring.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 1016cf13a02a..445afda927f4 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -486,6 +486,7 @@ struct io_poll_iocb { struct file *file; struct wait_queue_head *head; __poll_t events; + int retries; struct wait_queue_entry wait; }; @@ -5749,6 +5750,14 @@ enum { IO_APOLL_READY }; +/* + * We can't reliably detect loops in repeated poll triggers and issue + * subsequently failing. But rather than fail these immediately, allow a + * certain amount of retries before we give up. Given that this condition + * should _rarely_ trigger even once, we should be fine with a larger value. + */ +#define APOLL_MAX_RETRY 128 + static int io_arm_poll_handler(struct io_kiocb *req) { const struct io_op_def *def = &io_op_defs[req->opcode]; @@ -5760,8 +5769,6 @@ static int io_arm_poll_handler(struct io_kiocb *req) if (!req->file || !file_can_poll(req->file)) return IO_APOLL_ABORTED; - if ((req->flags & (REQ_F_POLLED|REQ_F_PARTIAL_IO)) == REQ_F_POLLED) - return IO_APOLL_ABORTED; if (!def->pollin && !def->pollout) return IO_APOLL_ABORTED; @@ -5779,8 +5786,13 @@ static int io_arm_poll_handler(struct io_kiocb *req) if (req->flags & REQ_F_POLLED) { apoll = req->apoll; kfree(apoll->double_poll); + if (unlikely(!--apoll->poll.retries)) { + apoll->double_poll = NULL; + return IO_APOLL_ABORTED; + } } else { apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC); + apoll->poll.retries = APOLL_MAX_RETRY; } if (unlikely(!apoll)) return IO_APOLL_ABORTED; |