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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Jean, On Tue, Sep 13, 2022 at 01:27:03PM +0100, Jean-Philippe Brucker wrote: > External email: Use caution opening links or attachments > > > Hi Nicolin, > > On Tue, Sep 13, 2022 at 01:24:47AM -0700, Nicolin Chen wrote: > > Following the new rules in include/linux/iommu.h kdocs, update all drivers > > ->attach_dev callback functions to return ENODEV error code for all device > > specific errors. It particularly excludes EINVAL from being used for such > > error cases. For the same purpose, also replace one EINVAL with ENOMEM in > > mtk_iommu driver. > > > > Note that the virtio-iommu does a viommu_domain_map_identity() call, which > > returns either 0 or ENOMEM at this moment. Change to "return ret" directly > > to allow it to pass an EINVAL in the future. > [...] > > diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c > > index 80151176ba12..874c01634d2b 100644 > > --- a/drivers/iommu/virtio-iommu.c > > +++ b/drivers/iommu/virtio-iommu.c > > @@ -696,7 +696,7 @@ static int viommu_domain_finalise(struct viommu_endpoint *vdev, > > if (ret) { > > ida_free(&viommu->domain_ids, vdomain->id); > > vdomain->viommu = NULL; > > - return -EOPNOTSUPP; > > + return ret; > > I think in the future it will be too easy to forget about the constrained > return value of attach() while modifying some other part of the driver, > and let an external helper return EINVAL. So I'd rather not propagate ret > from outside of viommu_domain_attach() and finalise(). > > For the same reason I do prefer this solution over EMEDIUMTYPE, because > it's too tempting to use exotic errno when they seem appropriate instead > of boring ENODEV and EINVAL. The alternative would be adding a special > purpose code to linux/errno.h, similarly to EPROBE_DEFER, but that might > be excessive. > > Since we can't guarantee that APIs like virtio or ida won't ever return > EINVAL, we should set all return values: Thanks for the inputs. Assuming your attached patch isn't officially sent, I will group it into my next version. Similarly, I will also double check other drivers, to make sure all of them have explicit return values, other than "ret". _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel