From patchwork Tue Mar 6 20:48:18 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 10262941 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 4781A6055D for ; Tue, 6 Mar 2018 20:56:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3800F290D9 for ; Tue, 6 Mar 2018 20:56:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2C2EA29165; Tue, 6 Mar 2018 20:56:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 92F80290D9 for ; Tue, 6 Mar 2018 20:56:57 +0000 (UTC) Received: from localhost ([::1]:58130 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1etJdo-0007fl-9h for patchwork-qemu-devel@patchwork.kernel.org; Tue, 06 Mar 2018 15:56:56 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48487) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1etJWQ-0000oM-Px for qemu-devel@nongnu.org; Tue, 06 Mar 2018 15:49:21 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1etJWP-0005aq-Ke for qemu-devel@nongnu.org; Tue, 06 Mar 2018 15:49:18 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:50576 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1etJWL-0005Xy-Ds; Tue, 06 Mar 2018 15:49:13 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E8E97404085A; Tue, 6 Mar 2018 20:49:12 +0000 (UTC) Received: from localhost (ovpn-116-58.ams2.redhat.com [10.36.116.58]) by smtp.corp.redhat.com (Postfix) with ESMTP id 896E42024CAB; Tue, 6 Mar 2018 20:49:12 +0000 (UTC) From: Stefan Hajnoczi To: Date: Tue, 6 Mar 2018 20:48:18 +0000 Message-Id: <20180306204819.11266-2-stefanha@redhat.com> In-Reply-To: <20180306204819.11266-1-stefanha@redhat.com> References: <20180306204819.11266-1-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Tue, 06 Mar 2018 20:49:12 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Tue, 06 Mar 2018 20:49:12 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'stefanha@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH 1/2] block: let blk_add/remove_aio_context_notifier() tolerate BDS changes 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: Kevin Wolf , Stefano Panella , Stefan Hajnoczi , qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Commit 2019ba0a0197 ("block: Add AioContextNotifier functions to BB") added blk_add/remove_aio_context_notifier() and implemented them by passing through the bdrv_*() equivalent. This doesn't work across bdrv_append(), which detaches child->bs and re-attaches it to a new BlockDriverState. When blk_remove_aio_context_notifier() is called we will access the new BDS instead of the one where the notifier was added! From the point of view of the blk_*() API user, changes to the root BDS should be transparent. This patch maintains a list of AioContext notifiers in BlockBackend and adds/removes them from the BlockDriverState as needed. Reported-by: Stefano Panella Cc: Max Reitz Signed-off-by: Stefan Hajnoczi Reviewed-by: Eric Blake Reviewed-by: Max Reitz --- block/block-backend.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++ block/trace-events | 2 ++ 2 files changed, 65 insertions(+) diff --git a/block/block-backend.c b/block/block-backend.c index 94ffbb6a60..aa27698820 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -31,6 +31,13 @@ static AioContext *blk_aiocb_get_aio_context(BlockAIOCB *acb); +typedef struct BlockBackendAioNotifier { + void (*attached_aio_context)(AioContext *new_context, void *opaque); + void (*detach_aio_context)(void *opaque); + void *opaque; + QLIST_ENTRY(BlockBackendAioNotifier) list; +} BlockBackendAioNotifier; + struct BlockBackend { char *name; int refcnt; @@ -69,6 +76,7 @@ struct BlockBackend { bool allow_write_beyond_eof; NotifierList remove_bs_notifiers, insert_bs_notifiers; + QLIST_HEAD(, BlockBackendAioNotifier) aio_notifiers; int quiesce_counter; VMChangeStateEntry *vmsh; @@ -239,6 +247,36 @@ static int blk_root_inactivate(BdrvChild *child) return 0; } +static void blk_root_attach(BdrvChild *child) +{ + BlockBackend *blk = child->opaque; + BlockBackendAioNotifier *notifier; + + trace_blk_root_attach(child, blk, child->bs); + + QLIST_FOREACH(notifier, &blk->aio_notifiers, list) { + bdrv_add_aio_context_notifier(child->bs, + notifier->attached_aio_context, + notifier->detach_aio_context, + notifier->opaque); + } +} + +static void blk_root_detach(BdrvChild *child) +{ + BlockBackend *blk = child->opaque; + BlockBackendAioNotifier *notifier; + + trace_blk_root_detach(child, blk, child->bs); + + QLIST_FOREACH(notifier, &blk->aio_notifiers, list) { + bdrv_remove_aio_context_notifier(child->bs, + notifier->attached_aio_context, + notifier->detach_aio_context, + notifier->opaque); + } +} + static const BdrvChildRole child_root = { .inherit_options = blk_root_inherit_options, @@ -252,6 +290,9 @@ static const BdrvChildRole child_root = { .activate = blk_root_activate, .inactivate = blk_root_inactivate, + + .attach = blk_root_attach, + .detach = blk_root_detach, }; /* @@ -279,6 +320,7 @@ BlockBackend *blk_new(uint64_t perm, uint64_t shared_perm) notifier_list_init(&blk->remove_bs_notifiers); notifier_list_init(&blk->insert_bs_notifiers); + QLIST_INIT(&blk->aio_notifiers); QTAILQ_INSERT_TAIL(&block_backends, blk, link); return blk; @@ -356,6 +398,7 @@ static void blk_delete(BlockBackend *blk) } assert(QLIST_EMPTY(&blk->remove_bs_notifiers.notifiers)); assert(QLIST_EMPTY(&blk->insert_bs_notifiers.notifiers)); + assert(QLIST_EMPTY(&blk->aio_notifiers)); QTAILQ_REMOVE(&block_backends, blk, link); drive_info_del(blk->legacy_dinfo); block_acct_cleanup(&blk->stats); @@ -1813,8 +1856,15 @@ void blk_add_aio_context_notifier(BlockBackend *blk, void (*attached_aio_context)(AioContext *new_context, void *opaque), void (*detach_aio_context)(void *opaque), void *opaque) { + BlockBackendAioNotifier *notifier; BlockDriverState *bs = blk_bs(blk); + notifier = g_new(BlockBackendAioNotifier, 1); + notifier->attached_aio_context = attached_aio_context; + notifier->detach_aio_context = detach_aio_context; + notifier->opaque = opaque; + QLIST_INSERT_HEAD(&blk->aio_notifiers, notifier, list); + if (bs) { bdrv_add_aio_context_notifier(bs, attached_aio_context, detach_aio_context, opaque); @@ -1827,12 +1877,25 @@ void blk_remove_aio_context_notifier(BlockBackend *blk, void (*detach_aio_context)(void *), void *opaque) { + BlockBackendAioNotifier *notifier; BlockDriverState *bs = blk_bs(blk); if (bs) { bdrv_remove_aio_context_notifier(bs, attached_aio_context, detach_aio_context, opaque); } + + QLIST_FOREACH(notifier, &blk->aio_notifiers, list) { + if (notifier->attached_aio_context == attached_aio_context && + notifier->detach_aio_context == detach_aio_context && + notifier->opaque == opaque) { + QLIST_REMOVE(notifier, list); + g_free(notifier); + return; + } + } + + abort(); } void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify) diff --git a/block/trace-events b/block/trace-events index 02dd80ff0c..7493d521dc 100644 --- a/block/trace-events +++ b/block/trace-events @@ -7,6 +7,8 @@ bdrv_lock_medium(void *bs, bool locked) "bs %p locked %d" # block/block-backend.c blk_co_preadv(void *blk, void *bs, int64_t offset, unsigned int bytes, int flags) "blk %p bs %p offset %"PRId64" bytes %u flags 0x%x" blk_co_pwritev(void *blk, void *bs, int64_t offset, unsigned int bytes, int flags) "blk %p bs %p offset %"PRId64" bytes %u flags 0x%x" +blk_root_attach(void *child, void *blk, void *bs) "child %p blk %p bs %p" +blk_root_detach(void *child, void *blk, void *bs) "child %p blk %p bs %p" # block/io.c bdrv_co_preadv(void *bs, int64_t offset, int64_t nbytes, unsigned int flags) "bs %p offset %"PRId64" nbytes %"PRId64" flags 0x%x"