From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49587) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f9H00-0005dA-CW for qemu-devel@nongnu.org; Thu, 19 Apr 2018 17:21:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f9Gzz-00013y-BC for qemu-devel@nongnu.org; Thu, 19 Apr 2018 17:21:48 -0400 References: <20180416114414.18406-1-vsementsov@virtuozzo.com> <20180416114414.18406-3-vsementsov@virtuozzo.com> From: John Snow Message-ID: Date: Thu, 19 Apr 2018 17:21:37 -0400 MIME-Version: 1.0 In-Reply-To: <20180416114414.18406-3-vsementsov@virtuozzo.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 2/7] dirty-bitmaps: fix comment about dirty_bitmap_mutex List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, qemu-block@nongnu.org Cc: kwolf@redhat.com, famz@redhat.com, armbru@redhat.com, mreitz@redhat.com, pbonzini@redhat.com, den@openvz.org On 04/16/2018 07:44 AM, Vladimir Sementsov-Ogievskiy wrote: > Clarify first two cases and fix Modify -> Any access in third case. > Also, drop 'only' from third case, as it a bit confuses, when thinking > about case where we modify BdrvDirtyBitmap and access HBitmap. > > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > include/block/block_int.h | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/include/block/block_int.h b/include/block/block_int.h > index c4dd1d4bb8..189666efa5 100644 > --- a/include/block/block_int.h > +++ b/include/block/block_int.h > @@ -709,10 +709,14 @@ struct BlockDriverState { > uint64_t write_threshold_offset; > NotifierWithReturn write_threshold_notifier; > > - /* Writing to the list requires the BQL _and_ the dirty_bitmap_mutex. > - * Reading from the list can be done with either the BQL or the > - * dirty_bitmap_mutex. Modifying a bitmap only requires > - * dirty_bitmap_mutex. */ > + /* Writing to the list (i.e. to any field of BdrvDirtyBitmap or to the > + * list-head) requires both the BQL _and_ the dirty_bitmap_mutex. > + * > + * Reading from the list (from any field of BdrvDirtyBitmap or from the > + * list-head) can be done with either the BQL or the dirty_bitmap_mutex. > + * > + * Any access to underlying HBitmap requires dirty_bitmap_mutex. "to the underlying HBitmap," probably. > + */ > QemuMutex dirty_bitmap_mutex; > QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps; > > Reviewed-by: John Snow