From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38958) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YuOkw-0005VI-6M for qemu-devel@nongnu.org; Mon, 18 May 2015 13:23:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YuOku-0008JV-NH for qemu-devel@nongnu.org; Mon, 18 May 2015 13:23:10 -0400 Message-ID: <555A1FE8.9020905@redhat.com> Date: Mon, 18 May 2015 19:22:48 +0200 From: Max Reitz MIME-Version: 1.0 References: <1431669868-26804-1-git-send-email-famz@redhat.com> <1431669868-26804-3-git-send-email-famz@redhat.com> In-Reply-To: <1431669868-26804-3-git-send-email-famz@redhat.com> Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 02/12] block: Add op blocker notifier list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Fam Zheng , qemu-devel@nongnu.org Cc: Kevin Wolf , qemu-block@nongnu.org, jcody@redhat.com, armbru@redhat.com, Stefan Hajnoczi , pbonzini@redhat.com On 15.05.2015 08:04, Fam Zheng wrote: > BDS users can register a notifier and get notified about op blocker > changes. > > Signed-off-by: Fam Zheng > --- > block.c | 35 +++++++++++++++++++++++++++++++++++ > include/block/block.h | 8 ++++++++ > include/block/block_int.h | 3 +++ > 3 files changed, 46 insertions(+) > > diff --git a/block.c b/block.c > index 7904098..178e186 100644 > --- a/block.c > +++ b/block.c > @@ -3375,6 +3375,19 @@ struct BdrvOpBlocker { > QLIST_ENTRY(BdrvOpBlocker) list; > }; > > +/* Add a notifier which will be notified when the first blocker of some type is > + * added to bs, or when the last blocker is removed. The notifier handler > + * should receive a BlockOpEvent data. > + * > + * Caller must hold bs->aio_context; the notifier handler is also called with > + * it hold. *held (I think) With that fixed: Reviewed-by: Max Reitz (Although I'm missing a place where the notifiers are freed (on bdrv_delete()/bdrv_close()), but maybe that's done in a different patch) > + */ > +void bdrv_op_blocker_add_notifier(BlockDriverState *bs, > + Notifier *notifier) > +{ > + notifier_list_add(&bs->op_blocker_notifiers, notifier); > +} > + > bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp) > { > BdrvOpBlocker *blocker; > @@ -3391,26 +3404,48 @@ bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp) > return false; > } > > +static void bdrv_op_blocker_notify(BlockDriverState *bs, BlockOpType op, > + Error *reason, bool blocking) > +{ > + BlockOpEvent event = (BlockOpEvent) { > + op = op, > + reason = reason, > + blocking = blocking, > + }; > + > + notifier_list_notify(&bs->op_blocker_notifiers, &event); > +} > + > void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason) > { > + bool blocked; > BdrvOpBlocker *blocker; > assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); > > blocker = g_new0(BdrvOpBlocker, 1); > blocker->reason = reason; > + blocked = !QLIST_EMPTY(&bs->op_blockers[op]); > QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list); > + if (!blocked) { > + bdrv_op_blocker_notify(bs, op, reason, true); > + } > } > > void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason) > { > + bool blocked; > BdrvOpBlocker *blocker, *next; > assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX); > + blocked = !QLIST_EMPTY(&bs->op_blockers[op]); > QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) { > if (blocker->reason == reason) { > QLIST_REMOVE(blocker, list); > g_free(blocker); > } > } > + if (blocked && QLIST_EMPTY(&bs->op_blockers[op])) { > + bdrv_op_blocker_notify(bs, op, reason, false); > + } > } > > void bdrv_op_block_all(BlockDriverState *bs, Error *reason) > diff --git a/include/block/block.h b/include/block/block.h > index 906fb31..3420b2c 100644 > --- a/include/block/block.h > +++ b/include/block/block.h > @@ -163,6 +163,12 @@ typedef enum BlockOpType { > BLOCK_OP_TYPE_MAX, > } BlockOpType; > > +typedef struct { > + BlockOpType type; > + Error *reason; > + bool blocking; > +} BlockOpEvent; > + > void bdrv_iostatus_enable(BlockDriverState *bs); > void bdrv_iostatus_reset(BlockDriverState *bs); > void bdrv_iostatus_disable(BlockDriverState *bs); > @@ -491,6 +497,8 @@ void bdrv_disable_copy_on_read(BlockDriverState *bs); > void bdrv_ref(BlockDriverState *bs); > void bdrv_unref(BlockDriverState *bs); > > +void bdrv_op_blocker_add_notifier(BlockDriverState *bs, > + Notifier *notifier); > bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp); > void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason); > void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason); > diff --git a/include/block/block_int.h b/include/block/block_int.h > index db29b74..29d1c84 100644 > --- a/include/block/block_int.h > +++ b/include/block/block_int.h > @@ -418,6 +418,9 @@ struct BlockDriverState { > /* operation blockers */ > QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX]; > > + /* Callback when one list in op_blockers has "empty" status change. */ > + NotifierList op_blocker_notifiers; > + > /* long-running background operation */ > BlockJob *job; >