io_uring: don't allow netpolling with SETUP_IOPOLL

IORING_SETUP_IOPOLL rings don't have any netpoll handling, let's fail
attempts to register netpolling in this case, there might be people who
will mix up IOPOLL and netpoll.

Cc: stable@vger.kernel.org
Fixes: ef1186c1a875b ("io_uring: add register/unregister napi function")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1e7553aee0a8ae4edec6742cd6dd0c1e6914fba8.1721819383.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/napi.c b/io_uring/napi.c
index 762254a7ff3ffc0c9ee61897f7fac4a06ed5ca4b..327e5f3a8abe01c481440081307a4f7d206b1da3 100644 (file)
--- a/io_uring/napi.c
+++ b/io_uring/napi.c
@@ -222,6 +222,8 @@ int io_register_napi(struct io_ring_ctx *ctx, void __user *arg)
        };
        struct io_uring_napi napi;
 
+       if (ctx->flags & IORING_SETUP_IOPOLL)
+               return -EINVAL;
        if (copy_from_user(&napi, arg, sizeof(napi)))
                return -EFAULT;
        if (napi.pad[0] || napi.pad[1] || napi.pad[2] || napi.resv)