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 X-Spam-Level: X-Spam-Status: No, score=-6.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A8777C04AA8 for ; Tue, 30 Apr 2019 11:50:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 74BDD217D6 for ; Tue, 30 Apr 2019 11:50:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556625033; bh=u/7bNiFXHlXiSpvKf6zXVsjpXVoJ5NO9TeUy2831uKg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=QfJVJFECTYmuaFM8a2vCvVMi/89jsdg/+fTpzBHnEqGUJwa0yB2sc2eYsktCOmz6R MhiHT2+yst63OirPI95teDt5s0p9HAJID2tlI7UNm1bTSgDH4LPngWkoVX/X4MEmbc iI1BNemHMi+Ss/NZZ+6MLf5wuPlYKVFu1wMbenFk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731217AbfD3Lub (ORCPT ); Tue, 30 Apr 2019 07:50:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:37542 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730312AbfD3Lu2 (ORCPT ); Tue, 30 Apr 2019 07:50:28 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3DC2D20449; Tue, 30 Apr 2019 11:50:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556625027; bh=u/7bNiFXHlXiSpvKf6zXVsjpXVoJ5NO9TeUy2831uKg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wcofmEmTrZd8x4RrNX6hp9AooGg05zf7OrKOdUX0gVpk9KP8pMQjRht9yl3oMjEti 9JKBgIKdxMq5bUwIPTBJQp8GTq93Zv0ciTaacBNzcSIubnzkUKrcZIR9azV5vBxE8+ LpxQGOzCw5PwqokCOUfis3/UJ20GgKzzs/85sGXY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Linus Torvalds , Al Viro , Guenter Roeck Subject: [PATCH 5.0 64/89] pin iocb through aio. Date: Tue, 30 Apr 2019 13:38:55 +0200 Message-Id: <20190430113612.718349457@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190430113609.741196396@linuxfoundation.org> References: <20190430113609.741196396@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Linus Torvalds commit b53119f13a04879c3bf502828d99d13726639ead upstream. aio_poll() is not the only case that needs file pinned; worse, while aio_read()/aio_write() can live without pinning iocb itself, the proof is rather brittle and can easily break on later changes. Signed-off-by: Linus Torvalds Signed-off-by: Al Viro Cc: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- fs/aio.c | 37 +++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 16 deletions(-) --- a/fs/aio.c +++ b/fs/aio.c @@ -1022,6 +1022,9 @@ static bool get_reqs_available(struct ki /* aio_get_req * Allocate a slot for an aio request. * Returns NULL if no requests are free. + * + * The refcount is initialized to 2 - one for the async op completion, + * one for the synchronous code that does this. */ static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx) { @@ -1034,7 +1037,7 @@ static inline struct aio_kiocb *aio_get_ percpu_ref_get(&ctx->reqs); req->ki_ctx = ctx; INIT_LIST_HEAD(&req->ki_list); - refcount_set(&req->ki_refcnt, 0); + refcount_set(&req->ki_refcnt, 2); req->ki_eventfd = NULL; return req; } @@ -1067,15 +1070,18 @@ out: return ret; } +static inline void iocb_destroy(struct aio_kiocb *iocb) +{ + if (iocb->ki_filp) + fput(iocb->ki_filp); + percpu_ref_put(&iocb->ki_ctx->reqs); + kmem_cache_free(kiocb_cachep, iocb); +} + static inline void iocb_put(struct aio_kiocb *iocb) { - if (refcount_read(&iocb->ki_refcnt) == 0 || - refcount_dec_and_test(&iocb->ki_refcnt)) { - if (iocb->ki_filp) - fput(iocb->ki_filp); - percpu_ref_put(&iocb->ki_ctx->reqs); - kmem_cache_free(kiocb_cachep, iocb); - } + if (refcount_dec_and_test(&iocb->ki_refcnt)) + iocb_destroy(iocb); } static void aio_fill_event(struct io_event *ev, struct aio_kiocb *iocb, @@ -1749,9 +1755,6 @@ static ssize_t aio_poll(struct aio_kiocb INIT_LIST_HEAD(&req->wait.entry); init_waitqueue_func_entry(&req->wait, aio_poll_wake); - /* one for removal from waitqueue, one for this function */ - refcount_set(&aiocb->ki_refcnt, 2); - mask = vfs_poll(req->file, &apt.pt) & req->events; if (unlikely(!req->head)) { /* we did not manage to set up a waitqueue, done */ @@ -1782,7 +1785,6 @@ out: if (mask) aio_poll_complete(aiocb, mask); - iocb_put(aiocb); return 0; } @@ -1873,18 +1875,21 @@ static int __io_submit_one(struct kioctx break; } + /* Done with the synchronous reference */ + iocb_put(req); + /* * If ret is 0, we'd either done aio_complete() ourselves or have * arranged for that to be done asynchronously. Anything non-zero * means that we need to destroy req ourselves. */ - if (ret) - goto out_put_req; - return 0; + if (!ret) + return 0; + out_put_req: if (req->ki_eventfd) eventfd_ctx_put(req->ki_eventfd); - iocb_put(req); + iocb_destroy(req); out_put_reqs_available: put_reqs_available(ctx, 1); return ret;