From patchwork Mon Jun 5 12:38:54 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 771240 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3whF2p1RjLz9s2P for ; Mon, 5 Jun 2017 22:47:30 +1000 (AEST) Received: from localhost ([::1]:33166 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dHrPr-0006mL-PA for incoming@patchwork.ozlabs.org; Mon, 05 Jun 2017 08:47:27 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41595) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dHrHy-0008Ls-4M for qemu-devel@nongnu.org; Mon, 05 Jun 2017 08:39:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dHrHx-0005qi-05 for qemu-devel@nongnu.org; Mon, 05 Jun 2017 08:39:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38734) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dHrHw-0005pY-Ms for qemu-devel@nongnu.org; Mon, 05 Jun 2017 08:39:16 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BFBBF3D957 for ; Mon, 5 Jun 2017 12:39:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com BFBBF3D957 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=pbonzini@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com BFBBF3D957 Received: from donizetti.redhat.com (ovpn-117-97.ams2.redhat.com [10.36.117.97]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v55Cd83G010640; Mon, 5 Jun 2017 08:39:14 -0400 From: Paolo Bonzini To: qemu-devel@nongnu.org Date: Mon, 5 Jun 2017 14:38:54 +0200 Message-Id: <20170605123908.18777-6-pbonzini@redhat.com> In-Reply-To: <20170605123908.18777-1-pbonzini@redhat.com> References: <20170605123908.18777-1-pbonzini@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Mon, 05 Jun 2017 12:39:15 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 05/19] block: access wakeup with atomic ops X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: famz@redhat.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Reviewed-by: Stefan Hajnoczi Signed-off-by: Paolo Bonzini --- block/io.c | 3 ++- block/nfs.c | 4 +++- block/sheepdog.c | 3 ++- include/block/block.h | 5 +++-- include/block/block_int.h | 7 +++++-- 5 files changed, 15 insertions(+), 7 deletions(-) diff --git a/block/io.c b/block/io.c index d76202b452..4a598299a9 100644 --- a/block/io.c +++ b/block/io.c @@ -501,7 +501,8 @@ static void dummy_bh_cb(void *opaque) void bdrv_wakeup(BlockDriverState *bs) { - if (bs->wakeup) { + /* The barrier (or an atomic op) is in the caller. */ + if (atomic_read(&bs->wakeup)) { aio_bh_schedule_oneshot(qemu_get_aio_context(), dummy_bh_cb, NULL); } } diff --git a/block/nfs.c b/block/nfs.c index 848b2c0bb0..18c87d2f25 100644 --- a/block/nfs.c +++ b/block/nfs.c @@ -730,7 +730,9 @@ nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data, if (task->ret < 0) { error_report("NFS Error: %s", nfs_get_error(nfs)); } - task->complete = 1; + + /* Set task->complete before reading bs->wakeup. */ + atomic_mb_set(&task->complete, 1); bdrv_wakeup(task->bs); } diff --git a/block/sheepdog.c b/block/sheepdog.c index a18315a1ca..5ebf5d9fbb 100644 --- a/block/sheepdog.c +++ b/block/sheepdog.c @@ -698,7 +698,8 @@ out: srco->co = NULL; srco->ret = ret; - srco->finished = true; + /* Set srco->finished before reading bs->wakeup. */ + atomic_mb_set(&srco->finished, true); if (srco->bs) { bdrv_wakeup(srco->bs); } diff --git a/include/block/block.h b/include/block/block.h index 9b355e92d8..a4f09df95a 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -402,7 +402,8 @@ void bdrv_drain_all(void); * block_job_defer_to_main_loop for how to do it). \ */ \ assert(!bs_->wakeup); \ - bs_->wakeup = true; \ + /* Set bs->wakeup before evaluating cond. */ \ + atomic_mb_set(&bs_->wakeup, true); \ while (busy_) { \ if ((cond)) { \ waited_ = busy_ = true; \ @@ -414,7 +415,7 @@ void bdrv_drain_all(void); waited_ |= busy_; \ } \ } \ - bs_->wakeup = false; \ + atomic_set(&bs_->wakeup, false); \ } \ waited_; }) diff --git a/include/block/block_int.h b/include/block/block_int.h index e5f19eb24c..dd09e0071b 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -604,8 +604,6 @@ struct BlockDriverState { /* Callback before write request is processed */ NotifierWithReturnList before_write_notifiers; - bool wakeup; - /* Offset after the highest byte written to */ uint64_t wr_highest_offset; @@ -636,6 +634,11 @@ struct BlockDriverState { unsigned int in_flight; unsigned int serialising_in_flight; + /* Internal to BDRV_POLL_WHILE and bdrv_wakeup. Accessed with atomic + * ops. + */ + bool wakeup; + /* do we need to tell the quest if we have a volatile write cache? */ int enable_write_cache;