From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68D4BC43334 for ; Fri, 3 Jun 2022 17:53:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345505AbiFCRxD (ORCPT ); Fri, 3 Jun 2022 13:53:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345815AbiFCRu1 (ORCPT ); Fri, 3 Jun 2022 13:50:27 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E8E4F590BE; Fri, 3 Jun 2022 10:46:22 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 60FE7B82430; Fri, 3 Jun 2022 17:46:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C92DC385A9; Fri, 3 Jun 2022 17:46:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654278380; bh=EZhGGfDHtywe2gnNldpG1wtwGHl1pTHgN+kbhnSDUkA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eFQvZLegxb7+4d4sPSHdw2Ve3AGz9Wbhq7rVH6EEcN1YkM25dqNWyhyvsjKJ6w8H8 Kcjy1YUErzGzjm1A9sIaiX2ZfmKxv1WG1GVjFdbQBKe3Hl+j1DcpQKVomn8otE+JaU WrsF774pm6FQ7u1lTlcOhXEprP1dQ4NO4j0DFd0Y= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Pavel Begunkov Subject: [PATCH 5.10 14/53] io_uring: fix using under-expanded iters Date: Fri, 3 Jun 2022 19:42:59 +0200 Message-Id: <20220603173819.137177057@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220603173818.716010877@linuxfoundation.org> References: <20220603173818.716010877@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Pavel Begunkov [ upstream commit cd65869512ab5668a5d16f789bc4da1319c435c4 ] The issue was first described and addressed in 89c2b3b7491820 ("io_uring: reexpand under-reexpanded iters"), but shortly after reimplemented as. cd65869512ab56 ("io_uring: use iov_iter state save/restore helpers"). Here we follow the approach from the second patch but without in-callback resubmissions, fixups for not yet supported in 5.10 short read retries and replacing iov_iter_state with iter copies to not pull even more dependencies, and because it's just much simpler. Signed-off-by: Pavel Begunkov Signed-off-by: Greg Kroah-Hartman --- fs/io_uring.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3389,6 +3389,7 @@ static int io_read(struct io_kiocb *req, struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct kiocb *kiocb = &req->rw.kiocb; struct iov_iter __iter, *iter = &__iter; + struct iov_iter iter_cp; struct io_async_rw *rw = req->async_data; ssize_t io_size, ret, ret2; bool no_async; @@ -3399,6 +3400,7 @@ static int io_read(struct io_kiocb *req, ret = io_import_iovec(READ, req, &iovec, iter, !force_nonblock); if (ret < 0) return ret; + iter_cp = *iter; io_size = iov_iter_count(iter); req->result = io_size; ret = 0; @@ -3434,7 +3436,7 @@ static int io_read(struct io_kiocb *req, if (req->file->f_flags & O_NONBLOCK) goto done; /* some cases will consume bytes even on error returns */ - iov_iter_revert(iter, io_size - iov_iter_count(iter)); + *iter = iter_cp; ret = 0; goto copy_iov; } else if (ret < 0) { @@ -3517,6 +3519,7 @@ static int io_write(struct io_kiocb *req struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct kiocb *kiocb = &req->rw.kiocb; struct iov_iter __iter, *iter = &__iter; + struct iov_iter iter_cp; struct io_async_rw *rw = req->async_data; ssize_t ret, ret2, io_size; @@ -3526,6 +3529,7 @@ static int io_write(struct io_kiocb *req ret = io_import_iovec(WRITE, req, &iovec, iter, !force_nonblock); if (ret < 0) return ret; + iter_cp = *iter; io_size = iov_iter_count(iter); req->result = io_size; @@ -3587,7 +3591,7 @@ done: } else { copy_iov: /* some cases will consume bytes even on error returns */ - iov_iter_revert(iter, io_size - iov_iter_count(iter)); + *iter = iter_cp; ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false); if (!ret) return -EAGAIN;