From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53181) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XigDr-0001fQ-0L for qemu-devel@nongnu.org; Mon, 27 Oct 2014 05:04:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XigDm-0008Jd-2z for qemu-devel@nongnu.org; Mon, 27 Oct 2014 05:04:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57775) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XigDl-0008JZ-SY for qemu-devel@nongnu.org; Mon, 27 Oct 2014 05:04:14 -0400 Message-ID: <544E0A80.3030102@redhat.com> Date: Mon, 27 Oct 2014 10:04:00 +0100 From: Max Reitz 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> <544E0694.1030101@kamp.de> In-Reply-To: <544E0694.1030101@kamp.de> 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: Peter Lieven , qemu-devel@nongnu.org Cc: kwolf@redhat.com, famz@redhat.com, benoit@irqsave.net, ronniesahlberg@gmail.com, armbru@redhat.com, stefanha@redhat.com On 2014-10-27 at 09:47, Peter Lieven wrote: > 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? sector_limits_lun2qemu()? :-) Max