From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-5486-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis.ws5.connectedcommunity.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 730749860C4 for ; Thu, 21 Feb 2019 16:22:47 +0000 (UTC) From: Stefan Hajnoczi Date: Thu, 21 Feb 2019 16:22:17 +0000 Message-Id: <20190221162219.9790-4-stefanha@redhat.com> In-Reply-To: <20190221162219.9790-1-stefanha@redhat.com> References: <20190221162219.9790-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [virtio-dev] [PATCH v3 3/5] virtio-blk: describe write zeroes unmap semantics To: virtio-dev@lists.oasis-open.org Cc: Jan Kiszka , Stefan Hajnoczi , "Michael S . Tsirkin" List-ID: Explain the meaning of the unmap flag. The details are already covered in the device normative section but mentioning it here makes the text easier to understand. Suggested-by: Michael S. Tsirkin Signed-off-by: Stefan Hajnoczi --- content.tex | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/content.tex b/content.tex index 4201c7e..8ea8320 100644 --- a/content.tex +++ b/content.tex @@ -3983,7 +3983,9 @@ struct virtio_blk_discard_write_zeroes { \field{sector} indicates the starting offset (in 512-byte units) of the segment, while \field{num_sectors} indicates the number of sectors in each -discarded range. \field{unmap} is only used for write zeroes command. +discarded range. \field{unmap} is only used in write zeroes commands and allows +the device to discard the specified range, provided that following reads return +zeroes. The final \field{status} byte is written by the device: either VIRTIO_BLK_S_OK for success, VIRTIO_BLK_S_IOERR for device or driver -- 2.20.1 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org