(Forwarding to all Hyper-V maintainers due to lack of response to Greg's question.
There's something about this patch which makes it keep falling through the cracks: in March when someone asked for this patch to be backported (http://lkml.iu.edu/hypermail/linux/kernel/1703.3/03056.html ) no one confirmed it should so Greg wound up dropping it (http://lkml.iu.edu/hypermail/linux/kernel/1703.3/04774.html ). Given this, can I urge people not to overlook this latest query...)
---------- Forwarded message ---------- From: Greg KH greg@kroah.com Date: 4 December 2017 at 12:10 Subject: Re: Hyper-V SSD passthrough fix backport To: Stephen Hemminger stephen@networkplumber.org Cc: Sitsofe Wheeler sitsofe@gmail.com, stable stable@vger.kernel.org, "Martin K. Petersen" martin.petersen@oracle.com
On Wed, Nov 29, 2017 at 03:21:08PM -0800, Stephen Hemminger wrote:
On Wed, 29 Nov 2017 12:09:03 +0000 Sitsofe Wheeler sitsofe@gmail.com wrote:
On 29 November 2017 at 10:40, Sitsofe Wheeler sitsofe@gmail.com wrote:
On 29 November 2017 at 08:11, Sitsofe Wheeler sitsofe@gmail.com wrote:
On 29 November 2017 at 08:06, Greg KH greg@kroah.com wrote:
On Tue, Nov 28, 2017 at 10:58:25PM +0000, Sitsofe Wheeler wrote:
I'd like to nominate f1c635b439a5c01776fe3a25b1e2dc546ea82e6f (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/dr... ) to be backported to 4.4 stable because it looks like without it passthrough SSD disks won't work and will generate faux devices. It is also being carried by Ubuntu: http://kernel.ubuntu.com/git/ubuntu/ubuntu-xenial.git/log/drivers/scsi/storv... along with other Hyper-V patches in their 4.4 tree.
I'm not 100% sure that this one will fix what is being seen but I'm coming to this conclusion based on https://bugs.launchpad.net/ubuntu/xenial/+source/linux/+bug/1679898/comments...
Can you test it to determine if this really does what you think it does to solve the problem? The changelog text makes it seem not necessary at all.
I agree the changelog makes it seem totally unnecessary but the changelog is wrong in this case :-) I have checked out 4.4.102 and built it, run it and hit the error. When applying the patch attached (which is basically f1c635b439a5c01776fe3a25b1e2dc546ea82e6f with the lines removing static int msft_blist_flags = BLIST_TRY_VPD_PAGES; moved about) and the problem was resolved.
I'm happy for others to weigh on what I'm seeing.
I will also note that this patch was deemed necessary/suitable for backporting to 4.9 and 4.10 back in May - (https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/log/... and https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/log/... ). Looking at https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/log/... perhaps this is also suitable for 4.1 stable too (but I haven't tested 4.1, only 4.4.102)...
One more data point - back in May (https://www.spinics.net/lists/stable/msg170046.html ) you noted this in relation to one of the stable patch requests for this: "it's interesting how you deleted the changelog comments here saying this was only needed for 4.11 and no older kernels :)"
and there's a follow up reply (https://www.spinics.net/lists/stable/msg170125.html ) where Stephen says:
"At the time I only had reports of problem with 4.11. But others ran into issue with 4.10 and 4.9"
The changelog was about where the problem was seen. It makes sense that this also occurs with other classes of storage devices; hadn't tried all the possible configurations.
So, what does the maintainer of the driver recommend here? Should I backport this patch, or not?
thanks,
greg k-h