Date: Tue, 13 Nov 2018 11:45:10 -0700 From: Scott Long <scottl@samsco.org> To: Harry Schmalzbauer <freebsd@omnilan.de> Cc: scsi@freebsd.org, freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: MSI allocation regression, still to be corrected in HEAD and please MFC before release/12.0 gets branched Message-ID: <34515651-9883-4490-A3EE-7206AE973757@samsco.org> In-Reply-To: <d28eee74-99dc-296b-fd19-ea2c1adec0ee@omnilan.de> References: <201707300653.v6U6rwLN099096@repo.freebsd.org> <597DA578.6030101@omnilan.de> <597F56A8.1060603@omnilan.de> <D18DFAD4-6E93-4AE2-BE15-EFF4D8ABCB2A@samsco.org> <59804C8C.1020003@omnilan.de> <e7d94e6a-89e8-ffa1-40da-7fb67e6bfc2b@omnilan.de> <78611650-D7A4-4B1D-A254-DB058E1AC1C6@samsco.org> <d99e383d-b09a-f3bd-f1e2-a6a808016347@omnilan.de> <A2AECF9F-2BB1-4FC0-8330-658336A3A4F0@samsco.org> <6e1e5f9f-4ece-dc9d-b059-08d52c9e6965@omnilan.de> <042090da-f73f-ce80-517c-0b1729d3d6e1@omnilan.de> <05D94EC4-D797-4246-96B5-6DC1494E7EA9@samsco.org> <d28eee74-99dc-296b-fd19-ea2c1adec0ee@omnilan.de>
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> On Nov 13, 2018, at 11:11 AM, Harry Schmalzbauer <freebsd@omnilan.de> =
wrote:
>=20
> Am 13.11.2018 um 19:02 schrieb Scott Long:
>>> On Nov 12, 2018, at 10:03 AM, Harry Schmalzbauer =
<freebsd@omnilan.de> wrote:
>>>=20
>>> Am 11.06.2018 um 20:28 schrieb Harry Schmalzbauer:
>>>> Am 05.06.2018 um 19:54 schrieb Scott Long:
>>>> =E2=80=A6
>>>>>>>> Late in the 11.2 phase, I identified this commit as a =
regression for MSI (non-x) alloctaion.
>>>>>>>> I have an idea what probably causes the problem here (INTx =
allocation, although MSI (and MSI-x) capability):
>>>>>>>> disable_msix is not 0 (I need to disable MSI-x because of =
ESXi-passthru=E2=80=A6).
>>>>>>>>=20
>>>>>>>> Corresponding lines:
>>>>>>>> {
>>>>>>>> device_t dev;
>>>>>>>> int error, msgs;
>>>>>>>>=20
>>>>>>>> dev =3D sc->mps_dev;
>>>>>>>> error =3D 0;
>>>>>>>> msgs =3D 0;
>>>>>>>>=20
>>>>>>>> if ((sc->disable_msix =3D=3D 0) &&
>>>>>>>> ((msgs =3D pci_msix_count(dev)) >=3D =
MPS_MSI_COUNT))
>>>>>>>> error =3D mps_alloc_msix(sc, MPS_MSI_COUNT);
>>>>>>>> if ((error !=3D 0) && (sc->disable_msi =3D=3D 0) &&
>>>>>>>> ((msgs =3D pci_msi_count(dev)) >=3D =
MPS_MSI_COUNT))
>>>>>>>> error =3D mps_alloc_msi(sc, MPS_MSI_COUNT);
>>>>>>>> if (error !=3D 0)
>>>>>>>> msgs =3D 0;
>>>>>>>>=20
>>>>>>>> sc->msi_msgs =3D msgs;
>>>>>>>> return (error);
>>>>>>>> }
>>>>>>>>=20
>>> =E2=80=A6
>>>>>>> Hi Harry,
>>>>>>> You are correct about the bug. Please change the line at the =
top of the function that reads
>>>>>>> error =3D 0;
>>>>>>> to
>>>>>>> error =3D ENXIO;
>>>>>>> Let me know if that fixes the MSI problem for you.
>>>>=20
>>>> =E2=80=A6
>>>>=20
>>> =E2=80=A6
>>>> Index: src/sys/dev/mps/mps_pci.c
>>>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
>>>> --- sys/dev/mps/mps_pci.c (Revision 334948)
>>>> +++ sys/dev/mps/mps_pci.c (Arbeitskopie)
>>>> @@ -244,7 +244,7 @@
>>>> int error, msgs;
>>>>=20
>>>> dev =3D sc->mps_dev;
>>>> - error =3D 0;
>>>> + error =3D ENXIO;
>>>> msgs =3D 0;
>>>>=20
>>>> if ((sc->disable_msix =3D=3D 0) &&
>>>>=20
>>>=20
>>> To my understanding, it's obvious that the way =
mps_pci_alloc_interrupts() currently works is unintended.
>>> This might not affect too many people, but is there a reason not to =
fix it?
>>>=20
>>> I already created a coresponding problem report: =
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D229267
>>> Anything else I should do?
>>>=20
>> Hi Harry,
>> Sorry for ignoring this for so long. I=E2=80=99m going to commit a =
fix today, but it won=E2=80=99t be the same one-line change.
>> Upon reviewing the code, I=E2=80=99d going to refactor it so it=E2=80=99=
s not so confusing and prone to these kinds of mistakes.
>> Thank you for the continued reminders to finish this.
>=20
> Hi Scott,
>=20
> thanks a lot, in fact I'm not surprised that you come up with a better =
solution than that quick fix :-)
> Had hoped someone else would do an intermediate commit to get it into =
12.0 in time, so you won't feel any time pressure - good job needs the =
time it needs, as long as the right person is doing the job.
>=20
> Unfortunately I don't have a non-productive setup where I could test =
before release/12.0 will be branched =E2=80=93 might be subject to =
change...
12.0 has completely different code from 11.x, and from my review of it =
last night it should be fine. If you have evidence that what=E2=80=99s =
currently in 12 is not working, please let me know ASAP.
Scott
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