2022-08-11 18:04:18

by Sudip Mukherjee

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Subject: build failure of next-20220811 due to d79b32c2e4a4 ("vdpa_sim_blk: add support for discard and write-zeroes")

Hi All,

Not sure if it has been reported, builds of arm64 with clang failed to
build next-20220811 with the error:

drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:201:3: error: expected expression
struct virtio_blk_discard_write_zeroes range;
^
drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:204:25: error: use of undeclared identifier 'range'
if (to_pull != sizeof(range)) {
^
drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:207:21: error: use of undeclared identifier 'range'
to_pull, sizeof(range));
^
drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:212:60: error: use of undeclared identifier 'range'
bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &range,
^
drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:222:38: error: use of undeclared identifier 'range'
sector = vdpasim64_to_cpu(vdpasim, range.sector);
^
drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:224:43: error: use of undeclared identifier 'range'
num_sectors = vdpasim32_to_cpu(vdpasim, range.num_sectors);
^
drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:225:37: error: use of undeclared identifier 'range'
flags = vdpasim32_to_cpu(vdpasim, range.flags);
^
drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:202:7: error: mixing declarations and code is incompatible with standards before C99 [-Werror,-Wdeclaration-after-statement]
u32 num_sectors, flags;
^
8 errors generated.


git bisect pointed to d79b32c2e4a4 ("vdpa_sim_blk: add support for discard and write-zeroes").
And, reverting that commit has fixed the build failure.

I will be happy to test any patch or provide any extra log if needed.


--
Regards
Sudip


2022-08-11 18:53:32

by Stefano Garzarella

[permalink] [raw]
Subject: Re: build failure of next-20220811 due to d79b32c2e4a4 ("vdpa_sim_blk: add support for discard and write-zeroes")

Hi Sudip,

On Thu, Aug 11, 2022 at 06:22:54PM +0100, Sudip Mukherjee (Codethink) wrote:
>Hi All,
>
>Not sure if it has been reported, builds of arm64 with clang failed to
>build next-20220811 with the error:
>
>drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:201:3: error: expected expression
> struct virtio_blk_discard_write_zeroes range;
> ^
>drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:204:25: error: use of undeclared identifier 'range'
> if (to_pull != sizeof(range)) {
> ^
>drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:207:21: error: use of undeclared identifier 'range'
> to_pull, sizeof(range));
> ^
>drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:212:60: error: use of undeclared identifier 'range'
> bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &range,
> ^
>drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:222:38: error: use of undeclared identifier 'range'
> sector = vdpasim64_to_cpu(vdpasim, range.sector);
> ^
>drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:224:43: error: use of undeclared identifier 'range'
> num_sectors = vdpasim32_to_cpu(vdpasim, range.num_sectors);
> ^
>drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:225:37: error: use of undeclared identifier 'range'
> flags = vdpasim32_to_cpu(vdpasim, range.flags);
> ^
>drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:202:7: error: mixing declarations and code is incompatible with standards before C99 [-Werror,-Wdeclaration-after-statement]
> u32 num_sectors, flags;
> ^
>8 errors generated.
>
>
>git bisect pointed to d79b32c2e4a4 ("vdpa_sim_blk: add support for discard and write-zeroes").
>And, reverting that commit has fixed the build failure.
>
>I will be happy to test any patch or provide any extra log if needed.

Thanks for the report, I already re-sent a new series with that patch
fixed:
https://lore.kernel.org/virtualization/[email protected]/T/#t

And it looks like it's already in Michael's tree:
https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next

Thanks,
Stefano

2022-08-11 18:55:01

by Nathan Chancellor

[permalink] [raw]
Subject: Re: build failure of next-20220811 due to d79b32c2e4a4 ("vdpa_sim_blk: add support for discard and write-zeroes")

On Thu, Aug 11, 2022 at 06:22:54PM +0100, Sudip Mukherjee (Codethink) wrote:
> Hi All,
>
> Not sure if it has been reported, builds of arm64 with clang failed to
> build next-20220811 with the error:
>
> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:201:3: error: expected expression
> struct virtio_blk_discard_write_zeroes range;
> ^
> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:204:25: error: use of undeclared identifier 'range'
> if (to_pull != sizeof(range)) {
> ^
> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:207:21: error: use of undeclared identifier 'range'
> to_pull, sizeof(range));
> ^
> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:212:60: error: use of undeclared identifier 'range'
> bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &range,
> ^
> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:222:38: error: use of undeclared identifier 'range'
> sector = vdpasim64_to_cpu(vdpasim, range.sector);
> ^
> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:224:43: error: use of undeclared identifier 'range'
> num_sectors = vdpasim32_to_cpu(vdpasim, range.num_sectors);
> ^
> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:225:37: error: use of undeclared identifier 'range'
> flags = vdpasim32_to_cpu(vdpasim, range.flags);
> ^
> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:202:7: error: mixing declarations and code is incompatible with standards before C99 [-Werror,-Wdeclaration-after-statement]
> u32 num_sectors, flags;
> ^
> 8 errors generated.
>
>
> git bisect pointed to d79b32c2e4a4 ("vdpa_sim_blk: add support for discard and write-zeroes").
> And, reverting that commit has fixed the build failure.
>
> I will be happy to test any patch or provide any extra log if needed.

I am very surprised GCC does not error out in the same way, since as far
as I understand it, labeled statements have to be followed by a
statement and a declaration is not a statement in C so braces are
needed. In fact, it seems like something changed (regressed?) between
GCC 10.x and 11.x?

https://godbolt.org/z/EYaGa1eE3

I am going to bisect GCC to find out whether or not that was
intentional. At any rate, isn't this the proper fix? I can send it as a
formal patch if desired.

Cheers,
Nathan

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
index db85df1d5073..067d4c2f7bf4 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim_blk.c
@@ -197,7 +197,7 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
break;

case VIRTIO_BLK_T_DISCARD:
- case VIRTIO_BLK_T_WRITE_ZEROES:
+ case VIRTIO_BLK_T_WRITE_ZEROES: {
struct virtio_blk_discard_write_zeroes range;
u32 num_sectors, flags;

@@ -253,6 +253,7 @@ static bool vdpasim_blk_handle_req(struct vdpasim *vdpasim,
}

break;
+ }

default:
dev_dbg(&vdpasim->vdpa.dev,

2022-08-11 19:17:04

by Stefano Garzarella

[permalink] [raw]
Subject: Re: build failure of next-20220811 due to d79b32c2e4a4 ("vdpa_sim_blk: add support for discard and write-zeroes")

On Thu, Aug 11, 2022 at 11:31:21AM -0700, Nathan Chancellor wrote:
>On Thu, Aug 11, 2022 at 06:22:54PM +0100, Sudip Mukherjee (Codethink) wrote:
>> Hi All,
>>
>> Not sure if it has been reported, builds of arm64 with clang failed to
>> build next-20220811 with the error:
>>
>> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:201:3: error: expected expression
>> struct virtio_blk_discard_write_zeroes range;
>> ^
>> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:204:25: error: use of undeclared identifier 'range'
>> if (to_pull != sizeof(range)) {
>> ^
>> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:207:21: error: use of undeclared identifier 'range'
>> to_pull, sizeof(range));
>> ^
>> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:212:60: error: use of undeclared identifier 'range'
>> bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &range,
>> ^
>> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:222:38: error: use of undeclared identifier 'range'
>> sector = vdpasim64_to_cpu(vdpasim, range.sector);
>> ^
>> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:224:43: error: use of undeclared identifier 'range'
>> num_sectors = vdpasim32_to_cpu(vdpasim, range.num_sectors);
>> ^
>> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:225:37: error: use of undeclared identifier 'range'
>> flags = vdpasim32_to_cpu(vdpasim, range.flags);
>> ^
>> drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:202:7: error: mixing declarations and code is incompatible with standards before C99 [-Werror,-Wdeclaration-after-statement]
>> u32 num_sectors, flags;
>> ^
>> 8 errors generated.
>>
>>
>> git bisect pointed to d79b32c2e4a4 ("vdpa_sim_blk: add support for discard and write-zeroes").
>> And, reverting that commit has fixed the build failure.
>>
>> I will be happy to test any patch or provide any extra log if needed.
>
>I am very surprised GCC does not error out in the same way, since as far
>as I understand it, labeled statements have to be followed by a
>statement and a declaration is not a statement in C so braces are
>needed. In fact, it seems like something changed (regressed?) between
>GCC 10.x and 11.x?
>
>https://godbolt.org/z/EYaGa1eE3

Interesting, I confirm that also gcc 12 does not warns/error.
This is my version:

$ gcc --version
gcc (GCC) 12.1.1 20220507 (Red Hat 12.1.1-1)

>
>I am going to bisect GCC to find out whether or not that was
>intentional. At any rate, isn't this the proper fix? I can send it as a
>formal patch if desired.

Yep, that was the fix and I already re-sent a new series with the patch
fixed:
https://lore.kernel.org/virtualization/[email protected]/T/#t

Michael already queued the new version in his tree:
https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next

Thanks,
Stefano

2022-08-11 21:23:51

by Nathan Chancellor

[permalink] [raw]
Subject: Re: build failure of next-20220811 due to d79b32c2e4a4 ("vdpa_sim_blk: add support for discard and write-zeroes")

On Thu, Aug 11, 2022 at 11:31:21AM -0700, Nathan Chancellor wrote:
> On Thu, Aug 11, 2022 at 06:22:54PM +0100, Sudip Mukherjee (Codethink) wrote:
> > Hi All,
> >
> > Not sure if it has been reported, builds of arm64 with clang failed to
> > build next-20220811 with the error:
> >
> > drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:201:3: error: expected expression
> > struct virtio_blk_discard_write_zeroes range;
> > ^
> > drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:204:25: error: use of undeclared identifier 'range'
> > if (to_pull != sizeof(range)) {
> > ^
> > drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:207:21: error: use of undeclared identifier 'range'
> > to_pull, sizeof(range));
> > ^
> > drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:212:60: error: use of undeclared identifier 'range'
> > bytes = vringh_iov_pull_iotlb(&vq->vring, &vq->out_iov, &range,
> > ^
> > drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:222:38: error: use of undeclared identifier 'range'
> > sector = vdpasim64_to_cpu(vdpasim, range.sector);
> > ^
> > drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:224:43: error: use of undeclared identifier 'range'
> > num_sectors = vdpasim32_to_cpu(vdpasim, range.num_sectors);
> > ^
> > drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:225:37: error: use of undeclared identifier 'range'
> > flags = vdpasim32_to_cpu(vdpasim, range.flags);
> > ^
> > drivers/vdpa/vdpa_sim/vdpa_sim_blk.c:202:7: error: mixing declarations and code is incompatible with standards before C99 [-Werror,-Wdeclaration-after-statement]
> > u32 num_sectors, flags;
> > ^
> > 8 errors generated.
> >
> >
> > git bisect pointed to d79b32c2e4a4 ("vdpa_sim_blk: add support for discard and write-zeroes").
> > And, reverting that commit has fixed the build failure.
> >
> > I will be happy to test any patch or provide any extra log if needed.
>
> I am very surprised GCC does not error out in the same way, since as far
> as I understand it, labeled statements have to be followed by a
> statement and a declaration is not a statement in C so braces are
> needed. In fact, it seems like something changed (regressed?) between
> GCC 10.x and 11.x?
>
> https://godbolt.org/z/EYaGa1eE3
>
> I am going to bisect GCC to find out whether or not that was
> intentional.

Just for the record, it was:

https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=8b7a9a249a63e066cff6e95db05a3158b4cc56cc

The clang developers are aware, it seems it will get implemented at some
point:

https://github.com/llvm/llvm-project/issues/56040

Cheers,
Nathan