From: Nicolin Chen <nicolinc@nvidia.com>
To: "Tian, Kevin" <kevin.tian@intel.com>
Cc: "quic_saipraka@quicinc.com" <quic_saipraka@quicinc.com>,
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Subject: Re: [PATCH v3 3/6] iommu: Add return value rules to attach_dev op and APIs
Date: Tue, 20 Sep 2022 12:26:52 -0700 [thread overview]
Message-ID: <YyoT/M+mFVqI5Y1T@Asurada-Nvidia> (raw)
In-Reply-To: <BN9PR11MB527658C31268EB4A8411EDE88C4C9@BN9PR11MB5276.namprd11.prod.outlook.com>
On Tue, Sep 20, 2022 at 06:24:58AM +0000, Tian, Kevin wrote:
> External email: Use caution opening links or attachments
>
>
> > From: Nicolin Chen <nicolinc@nvidia.com>
> > Sent: Thursday, September 15, 2022 3:54 PM
> >
> > +/**
> > + * iommu_attach_device - Attach a device to an IOMMU domain
> > + * @domain: IOMMU domain to attach
> > + * @dev: Device that will be attached
> > + *
> > + * Returns 0 on success and error code on failure
> > + *
> > + * Note that EINVAL may be returned as a soft failure if the domain and
> > device
> > + * are incompatible: if the domain has already been used or configured in
> > some
>
> I didn't get the meaning of the 'if' part.
It means that the failure of attaching the device to the domain is
due to the domain configuration.
> > + * way, attaching the same device to a different domain may succeed.
> > Otherwise,
> > + * it may still represent some fundamental problem.
>
> I'm not sure what the sentence after 'otherwise' actually adds to the
> caller. There is no way to differentiate incompatibility vs. fundamental
> problem, hence pointless for the caller to know this fact.
>
> IMHO just state that the caller can treat -EINVAL as soft failure indicating
> incompatibility issue between domain and device.
OK. I changed to:
+ * Note that EINVAL may be returned as a soft failure if the domain and device
+ * are incompatible due to some previous configuration of the domain, in which
+ * case attaching the same device to a different domain may succeed.
> Later for @attach_dev you can add that driver may return (but not
> recommend) -EINVAL for some fundamental problems.
OK.
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next prev parent reply other threads:[~2022-09-20 19:28 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-15 7:53 [PATCH v3 0/6] Define EINVAL as device/domain incompatibility Nicolin Chen
2022-09-15 7:53 ` [PATCH v3 3/6] iommu: Add return value rules to attach_dev op and APIs Nicolin Chen
2022-09-20 6:24 ` Tian, Kevin
2022-09-20 19:26 ` Nicolin Chen [this message]
2022-09-15 7:53 ` [PATCH v3 5/6] iommu: Use EINVAL for incompatible device/domain in ->attach_dev Nicolin Chen
2022-09-20 6:38 ` Tian, Kevin
2022-09-20 18:06 ` Jason Gunthorpe
2022-09-21 8:14 ` Tian, Kevin
2022-09-15 7:58 ` [PATCH v3 4/6] iommu: Regulate EINVAL in ->attach_dev callback functions Nicolin Chen
2022-09-20 6:29 ` Tian, Kevin
2022-09-20 16:08 ` Nicolin Chen
2022-09-15 7:58 ` [PATCH v3 6/6] iommu: Propagate ret for a potential soft failure EINVAL Nicolin Chen
2022-09-20 6:50 ` Tian, Kevin
2022-09-20 20:39 ` Nicolin Chen
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