From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH] blkif.h: enhance comments related to the discard feature Date: Fri, 17 Jan 2014 10:51:27 -0500 Message-ID: <6396d00a-660b-4601-a7da-bd69e1df9b0d@email.android.com> References: <1389736679-15637-1-git-send-email-olaf@aepfle.de> <52D955A902000078001149E2@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1W68Jq-0004F6-Pm for xen-devel@lists.xenproject.org; Thu, 23 Jan 2014 00:38:55 +0000 In-Reply-To: <52D955A902000078001149E2@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich Cc: xen-devel , Olaf Hering , Keir Fraser List-Id: xen-devel@lists.xenproject.org Jan Beulich wrote: >>>> On 14.01.14 at 22:57, Olaf Hering wrote: >> Also fix the name of the discard-alignment property, add the missing >'n'. >> >> Signed-off-by: Olaf Hering > >Konrad, > >you have been working on the discard stuff quite a bit iirc - any >chance you could take a look and send and ack/review? Sure - next week I will dig through the patches. > >Jan > >> --- >> xen/include/public/io/blkif.h | 16 ++++++++++++---- >> 1 file changed, 12 insertions(+), 4 deletions(-) >> >> diff --git a/xen/include/public/io/blkif.h >b/xen/include/public/io/blkif.h >> index 84eb7fd..515ea90 100644 >> --- a/xen/include/public/io/blkif.h >> +++ b/xen/include/public/io/blkif.h >> @@ -175,7 +175,7 @@ >> * >> *------------------------- Backend Device Properties >------------------------- >> * >> - * discard-aligment >> + * discard-alignment >> * Values: >> * Default Value: 0 >> * Notes: 4, 5 >> @@ -194,6 +194,7 @@ >> * discard-secure >> * Values: 0/1 (boolean) >> * Default Value: 0 >> + * Notes: 10 >> * >> * A value of "1" indicates that the backend can process >> BLKIF_OP_DISCARD >> * requests with the BLKIF_DISCARD_SECURE flag set. >> @@ -323,9 +324,14 @@ >> * For full interoperability, block front and backends should >publish >> * identical ring parameters, adjusted for unit differences, to >the >> * XenStore nodes used in both schemes. >> - * (4) Devices that support discard functionality may internally >allocate >> - * space (discardable extents) in units that are larger than the >> - * exported logical block size. >> + * (4) Devices that support discard functionality may internally >allocate >> space >> + * (discardable extents) in units that are larger than the >exported >> logical >> + * block size. If the backing device has such discardable >extents the >> + * backend must provide both discard-granularity and >discard-alignment. >> + * Backends supporting discard should include >discard-granularity and >> + * discard-alignment even if it supports discarding individual >sectors. >> + * Frontends should assume discard-alignment == 0 and >discard-granularity >> == >> + * sector size if these keys are missing. >> * (5) The discard-alignment parameter allows a physical device to >be >> * partitioned into virtual devices that do not necessarily >begin or >> * end on a discardable extent boundary. >> @@ -344,6 +350,8 @@ >> * grants that can be persistently mapped in the frontend >driver, but >> * due to the frontent driver implementation it should never be >bigger >> * than RING_SIZE * BLKIF_MAX_SEGMENTS_PER_REQUEST. >> + *(10) The discard-secure property may be present and will be set to >1 if >> the >> + * backing device supports secure discard. >> */ >> >> /* >> >> _______________________________________________ >> Xen-devel mailing list >> Xen-devel@lists.xen.org >> http://lists.xen.org/xen-devel