From 9af177ee3ef14c17ef10893c257fa4e2008a3d74 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 9 Mar 2022 16:46:07 -0700 Subject: [PATCH] io_uring: retry early for reads if we can poll Most of the logic in io_read() deals with regular files, and in some ways it would make sense to split the handling into S_IFREG and others. But at least for retry, we don't need to bother setting up a bunch of state just to abort in the loop later. In particular, don't bother forcing setup of async data for a normal non-vectored read when we don't need it. Signed-off-by: Jens Axboe --- fs/io_uring.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 3d30f7b07677f..4d8366bc226f1 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3773,6 +3773,9 @@ static int io_read(struct io_kiocb *req, unsigned int issue_flags) if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) { req->flags &= ~REQ_F_REISSUE; + /* if we can poll, just do that */ + if (req->opcode == IORING_OP_READ && file_can_poll(req->file)) + return -EAGAIN; /* IOPOLL retry should happen for io-wq threads */ if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL)) goto done;