From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50525) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XifxW-0005DX-Qb for qemu-devel@nongnu.org; Mon, 27 Oct 2014 04:47:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XifxR-0003O5-3P for qemu-devel@nongnu.org; Mon, 27 Oct 2014 04:47:26 -0400 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:56480 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XifxQ-0003Nz-Ow for qemu-devel@nongnu.org; Mon, 27 Oct 2014 04:47:21 -0400 Message-ID: <544E0694.1030101@kamp.de> Date: Mon, 27 Oct 2014 09:47:16 +0100 From: Peter Lieven MIME-Version: 1.0 References: <1414253919-3044-1-git-send-email-pl@kamp.de> <1414253919-3044-4-git-send-email-pl@kamp.de> <544E0216.2050400@redhat.com> <544E0412.6000405@kamp.de> <544E05FA.3060804@redhat.com> In-Reply-To: <544E05FA.3060804@redhat.com> Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCHv5 3/6] block/iscsi: set max_transfer_length List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Max Reitz , qemu-devel@nongnu.org Cc: kwolf@redhat.com, famz@redhat.com, benoit@irqsave.net, ronniesahlberg@gmail.com, armbru@redhat.com, stefanha@redhat.com On 27.10.2014 09:44, Max Reitz wrote: > On 2014-10-27 at 09:36, Peter Lieven wrote: >> On 27.10.2014 09:28, Max Reitz wrote: >>> On 2014-10-25 at 18:18, Peter Lieven wrote: >>>> Copy the max_xfer_len from the BlockLimits VPD or use the >>>> maximum value fitting in the CDB. >>>> >>>> Signed-off-by: Peter Lieven >>>> --- >>>> block/iscsi.c | 17 +++++++++++++++-- >>>> 1 file changed, 15 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/block/iscsi.c b/block/iscsi.c >>>> index 233f462..1ae4add 100644 >>>> --- a/block/iscsi.c >>>> +++ b/block/iscsi.c >>>> @@ -297,6 +297,11 @@ static int64_t sector_lun2qemu(int64_t sector, IscsiLun *iscsilun) >>>> return sector * iscsilun->block_size / BDRV_SECTOR_SIZE; >>>> } >>>> +static int nb_sectors_lun2qemu(int64_t sector, IscsiLun *iscsilun) >>>> +{ >>>> + return MIN(sector_lun2qemu(sector, iscsilun), INT_MAX); >>>> +} >>>> + >>>> static int64_t sector_qemu2lun(int64_t sector, IscsiLun *iscsilun) >>>> { >>>> return sector * BDRV_SECTOR_SIZE / iscsilun->block_size; >>>> @@ -1449,10 +1454,18 @@ static void iscsi_close(BlockDriverState *bs) >>>> static void iscsi_refresh_limits(BlockDriverState *bs, Error **errp) >>>> { >>>> - IscsiLun *iscsilun = bs->opaque; >>>> - >>>> /* We don't actually refresh here, but just return data queried in >>>> * iscsi_open(): iscsi targets don't change their limits. */ >>>> + >>>> + IscsiLun *iscsilun = bs->opaque; >>>> + uint32_t max_xfer_len = iscsilun->use_16_for_rw ? 0xffffffff : 0xffff; >>>> + >>>> + if (iscsilun->bl.max_xfer_len) { >>>> + max_xfer_len = MIN(max_xfer_len, iscsilun->bl.max_xfer_len); >>>> + } >>>> + >>>> + bs->bl.max_transfer_length = nb_sectors_lun2qemu(max_xfer_len, iscsilun); >>>> + >>>> if (iscsilun->lbp.lbpu) { >>>> if (iscsilun->bl.max_unmap < 0xffffffff) { >>>> bs->bl.max_discard = sector_lun2qemu(iscsilun->bl.max_unmap, >>> >>> Hm, seems strange to have a function called nb_sectors_lun2qemu() not only convert values, but also cap the result. But anyway: >> >> Would you give it another name? > > Aaah, looking for names... It's always the same horror... > > Hm, I just realized why it's nb_sectors, it just wasn't obvious to me that nb_sectors is always an int (and I think it might not be to others either). > > So maybe int_sector_lun2qemu() or even better sector_lun2qemu_int()? I always consider everything on the left of the "2" to be the original unit and everything on the right to be the result unit, maybe that confused me further (so > sector_lun2qemu_nb_sectors() is what I'd expect, although it's rather long). > > But I now see why you called the function that way and it seems fine to me. Just leaving it is fine, too. ;-) what about limits_lun2qemu ? It might give a hint that nobody uses it for sth else than limits? Peter