From: Christoph Hellwig <hch@infradead.org>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
Raj Ashok <ashok.raj@intel.com>,
Jean-Philippe Brucker <jean-philippe@linaro.com>,
LKML <linux-kernel@vger.kernel.org>,
iommu@lists.linux-foundation.org,
Alex Williamson <alex.williamson@redhat.com>,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH v2 1/3] iommu/uapi: Define uapi version and capabilities
Date: Thu, 26 Mar 2020 02:23:16 -0700 [thread overview]
Message-ID: <20200326092316.GA31648@infradead.org> (raw)
In-Reply-To: <1585178227-17061-2-git-send-email-jacob.jun.pan@linux.intel.com>
On Wed, Mar 25, 2020 at 04:17:05PM -0700, Jacob Pan wrote:
> Having a single UAPI version to govern the user-kernel data structures
> makes compatibility check straightforward. On the contrary, supporting
> combinations of multiple versions of the data can be a nightmare to
> maintain.
>
> This patch defines a unified UAPI version to be used for compatibility
> checks between user and kernel.
This is bullshit. Version numbers don't scale and we've avoided them
everywhere. You need need flags specifying specific behavior.
> +#define IOMMU_UAPI_VERSION 1
> +static inline int iommu_get_uapi_version(void)
> +{
> + return IOMMU_UAPI_VERSION;
> +}
Also inline functions like this in UAPI headers that actually get
included by userspace programs simply don't work.
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next prev parent reply other threads:[~2020-03-26 9:23 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-25 23:17 [PATCH v2 0/3] IOMMU user API enhancement Jacob Pan
2020-03-25 23:17 ` [PATCH v2 1/3] iommu/uapi: Define uapi version and capabilities Jacob Pan
2020-03-26 9:23 ` Christoph Hellwig [this message]
2020-03-26 16:44 ` Jacob Pan
2020-03-27 2:49 ` Tian, Kevin
2020-03-27 7:47 ` Christoph Hellwig
2020-03-27 23:53 ` Jacob Pan
2020-03-30 5:40 ` Tian, Kevin
2020-03-30 16:07 ` Jacob Pan
2020-03-31 6:06 ` Tian, Kevin
2020-03-31 15:54 ` Jacob Pan
2020-04-01 5:32 ` Tian, Kevin
2020-04-02 18:36 ` Jacob Pan
2020-04-13 20:41 ` Jacob Pan
2020-04-13 22:21 ` Alex Williamson
2020-04-14 5:05 ` Jacob Pan
2020-04-14 16:13 ` Alex Williamson
2020-04-14 17:13 ` Jacob Pan
2020-04-14 22:32 ` Jacob Pan
2020-04-14 23:47 ` Tian, Kevin
2020-04-15 15:38 ` Jacob Pan
2020-04-16 1:27 ` Tian, Kevin
2020-04-14 8:15 ` Christoph Hellwig
2020-04-14 8:11 ` Christoph Hellwig
2020-04-14 16:06 ` Jacob Pan
2020-03-25 23:17 ` [PATCH v2 2/3] iommu/uapi: Use unified UAPI version Jacob Pan
2020-03-25 23:17 ` [PATCH v2 3/3] iommu/uapi: Add helper function for size lookup Jacob Pan
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