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bh=NpvCvejhmqLiBfSx0m/ogEG5b5mXA0Q5Q2NrIbV4hTE=; b=ggvO/rtj7k4+jdS+7heJrakOIhRTWF6woa0DHSML1qElfGagj9tHCSSwEgI8P3bfyP/IPm 0CgtxXR2H/KEm6i64hE3Zmly98d8jA196Q79tQvwT2+K1+91IRSYbcdtm4g62XMIcgqIVQ tQXPGjUWOxP7iVJINWouXVyPi00aBKc= X-MC-Unique: rxJZJ1E3OnmQF2k_j_PVWg-1 From: Emanuele Giuseppe Esposito To: qemu-devel@nongnu.org Cc: Kevin Wolf , Hanna Reitz , John Snow , Stefan Hajnoczi , Paolo Bonzini , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, Emanuele Giuseppe Esposito Subject: [RFC PATCH 6/8] block-backend: implement .change_aio_ctx in child_root Date: Tue, 12 Jul 2022 17:19:09 -0400 Message-Id: <20220712211911.1302836-7-eesposit@redhat.com> In-Reply-To: <20220712211911.1302836-1-eesposit@redhat.com> References: <20220712211911.1302836-1-eesposit@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1657661259300100001 Content-Type: text/plain; charset="utf-8" blk_root_change_aio_ctx() is very similar to blk_root_can_set_aio_ctx(), but implements a new transaction so that if all check pass, the new transaction's .commit will take care of changing the BlockBackend AioContext. blk_root_set_aio_ctx_commit() is the same as blk_root_set_aio_ctx(). Note: bdrv_child_try_change_aio_context() is not called by anyone at this point. Signed-off-by: Emanuele Giuseppe Esposito --- block/block-backend.c | 54 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/block/block-backend.c b/block/block-backend.c index f425b00793..674eaaa2bf 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -138,6 +138,9 @@ static bool blk_root_can_set_aio_ctx(BdrvChild *child, = AioContext *ctx, GSList **ignore, Error **errp); static void blk_root_set_aio_ctx(BdrvChild *child, AioContext *ctx, GSList **ignore); +static bool blk_root_change_aio_ctx(BdrvChild *child, AioContext *ctx, + GSList **visited, Transaction *tran, + Error **errp); =20 static char *blk_root_get_parent_desc(BdrvChild *child) { @@ -336,6 +339,7 @@ static const BdrvChildClass child_root =3D { =20 .can_set_aio_ctx =3D blk_root_can_set_aio_ctx, .set_aio_ctx =3D blk_root_set_aio_ctx, + .change_aio_ctx =3D blk_root_change_aio_ctx, =20 .get_parent_aio_context =3D blk_root_get_parent_aio_context, }; @@ -2208,6 +2212,56 @@ int blk_set_aio_context(BlockBackend *blk, AioContex= t *new_context, return blk_do_set_aio_context(blk, new_context, true, errp); } =20 +typedef struct BdrvStateBlkRootContext { + AioContext *new_ctx; + BlockBackend *blk; +} BdrvStateBlkRootContext; + +static void blk_root_set_aio_ctx_commit(void *opaque) +{ + BdrvStateBlkRootContext *s =3D opaque; + BlockBackend *blk =3D s->blk; + + blk_do_set_aio_context(blk, s->new_ctx, false, &error_abort); +} + +static TransactionActionDrv set_blk_root_context =3D { + .commit =3D blk_root_set_aio_ctx_commit, + .clean =3D g_free, +}; + +static bool blk_root_change_aio_ctx(BdrvChild *child, AioContext *ctx, + GSList **visited, Transaction *tran, + Error **errp) +{ + BlockBackend *blk =3D child->opaque; + BdrvStateBlkRootContext *s; + + if (blk->allow_aio_context_change) { + goto finish; + } + + /* + * Only manually created BlockBackends that are not attached to anythi= ng + * can change their AioContext without updating their user. + */ + if (!blk->name || blk->dev) { + /* TODO Add BB name/QOM path */ + error_setg(errp, "Cannot change iothread of active block backend"); + return false; + } + +finish: + s =3D g_new(BdrvStateBlkRootContext, 1); + *s =3D (BdrvStateBlkRootContext) { + .new_ctx =3D ctx, + .blk =3D blk, + }; + + tran_add_tail(tran, &set_blk_root_context, s); + return true; +} + static bool blk_root_can_set_aio_ctx(BdrvChild *child, AioContext *ctx, GSList **ignore, Error **errp) { --=20 2.31.1