Date:   Sat, 27 Nov 2021 20:39:05 -0400
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Bjorn Helgaas <helgaas@kernel.org>,
        Marc Zygnier <maz@kernel.org>,
        Alex Williamson <alex.williamson@redhat.com>,
        Kevin Tian <kevin.tian@intel.com>,
        Megha Dey <megha.dey@intel.com>,
        Ashok Raj <ashok.raj@intel.com>, linux-pci@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Santosh Shilimkar <ssantosh@kernel.org>,
        iommu@lists.linux-foundation.org, dmaengine@vger.kernel.org,
        Stuart Yoder <stuyoder@gmail.com>,
        Laurentiu Tudor <laurentiu.tudor@nxp.com>,
        Nishanth Menon <nm@ti.com>, Tero Kristo <kristo@kernel.org>,
        linux-arm-kernel@lists.infradead.org, x86@kernel.org,
        Vinod Koul <vkoul@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Will Deacon <will@kernel.org>, Sinan Kaya <okaya@kernel.org>
Subject: Re: [patch 00/37] genirq/msi, PCI/MSI: Spring cleaning - Part 2
Message-ID: <20211128003905.GU4670@nvidia.com>
References: <20211126224100.303046749@linutronix.de>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20211126224100.303046749@linutronix.de>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?XAyuai/FfcqzYUyutbGOfi1yy1QcxAzOxUc0MYm0LIl0gNBWEQwEGEedtq5R?=
 =?us-ascii?Q?yw0ClOnO+bMqMiERVsTw1V7SL7iui97VbXKdQ9KwoimuA6IHqXsCFYx6sf6k?=
 =?us-ascii?Q?wFmW6VG9TCbW/BVU3QeoVu2zuTmtJNfiiwbOUjssAqJGOQoSqhe45s2iFlBL?=
 =?us-ascii?Q?ihwaT3JmkIzPpI2QVtZBmu9xuCN9Z3+Igf8Pio70cI1yAlk7GTMRw18GR7PB?=
 =?us-ascii?Q?WIoXJN1a6OqKeu3ophJmlL9rOxGa85+WjZ486L4jTDd51UU9m0SB3AsEiWp6?=
 =?us-ascii?Q?dr7SCkenEirUTQOX+tc5jBrNJpHTi1X4qJcr1qe2nri2nxQmK0VTG137RMKk?=
 =?us-ascii?Q?EVtynFgFJngKbHiTbGzr7dW/ZYh68gyRXKV75zyjhJ6UtNaQh1cTEcBnavb7?=
 =?us-ascii?Q?pmt1KwbIvtaUTQsRDDAMFILv18wGP6FGar9CpZDyGpjx/gOSDxI+6ZfJBZ+h?=
 =?us-ascii?Q?kpZdCf5nzfLUOpgcYw1/rtyvJyv+9RNVhv3+i6IpD1aU9jzKAS9Xs3G59RCj?=
 =?us-ascii?Q?Cc8Ivcgyb6cCFnL2zUAJw5pQ8Lzhy6Dq7JB8XNjEcb2jnz/MIB9Bi7NTLWYJ?=
 =?us-ascii?Q?zIn4eSgSFmkQfgdmndsEwC4A8Wrt8iiP9WtvKzahOOP/Pj3AX4z9u6XbA5St?=
 =?us-ascii?Q?X0o8ekXyLkuv6nNySte8Chpv+UGU1gYJs1spLKqyKlJrpxWRDCN3tkL2qu2W?=
 =?us-ascii?Q?IE0iN7T7eZiiYbJNLxF94XpyjecVDtcA3S5DhiHvFKVkQdxB6+RyZ+GvtGUu?=
 =?us-ascii?Q?hifcIeUj+ssk95ihRwob1db/MpiUDM04XcW9kxVEJZG73JqEpXYVWjiReaZF?=
 =?us-ascii?Q?swbQ1nNy0Eon1oX0oxLce/D6rjUuvQfIBsCP+X/wczKZAeER+Z3wWEeWlDCh?=
 =?us-ascii?Q?q4nwVkvumqGv5gkw81OzlZl18C2RpAJE1MzU+x+Jz9tCfaSTFLzq3agB1NAF?=
 =?us-ascii?Q?m+eR0LkaVaf6qRHEpq16OgaMbzMAb/L6kGyGeeaojxtb7bqD13IapJU/Boha?=
 =?us-ascii?Q?5h7JUzWa98p4jx2IU1nsR9t3DF2NJp2WucHAVujePbWZUy0rN8i5EZnX5REx?=
 =?us-ascii?Q?9560Fc77hz7W9SCPmg0oLpOXDso/j9stqjwtusHeyxKwCvcGbD9erBFaQHUQ?=
 =?us-ascii?Q?Gn3qRpjklY5NmDcU08p24PcoL3+bSgjCpvmizdUv210WCWK89AJDkTGk0/a9?=
 =?us-ascii?Q?3tH2q5NWeQKfhpD6azbTEFOapx/RLmFo8TfuE5SbK+UUd61bsuL7GMuJKYI8?=
 =?us-ascii?Q?MSjq7XBYeTfCDK6hWhYzAOIX2LpjePGGKNHCCTNilujkodrYs384bd1dBz89?=
 =?us-ascii?Q?i91BVJ3qL4onCYoXUCQp6dbRHHApeeL2mW4vcQHJTwLBuyLGdRbvR37rBWRn?=
 =?us-ascii?Q?4zeK4ZxFqN/DIfDXBoTT+T14eC1yXiLxi3948WcqhE/ujVGaZAkL3LXyet8u?=
 =?us-ascii?Q?XKs4hH5QIiTbeSwGLpHoRYph482nMzRlMgxW2vf9SgCfubWzmbZYoGByZ/lZ?=
 =?us-ascii?Q?HFlet1uDNPP1LX0LV4qQ/RWXhhqHXksXiMyFL4j7uRdmDSNq00JRzZjPSCoG?=
 =?us-ascii?Q?cSzvkVvvwNDexh8OjVY=3D?=
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 7c2fd1b1-3b57-4471-8ac1-08d9b2077bf6
X-MS-Exchange-CrossTenant-AuthSource: BL0PR12MB5506.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 28 Nov 2021 00:39:06.6235
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: xrqlAexVn5snThqU+O4W7p/UeFb4IBeJhx1NbfCGCxt53/579dmiNnEQzYixlyVY
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL1PR12MB5142
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Sat, Nov 27, 2021 at 02:21:17AM +0100, Thomas Gleixner wrote:
> This is the second part of [PCI]MSI refactoring which aims to provide the
> ability of expanding MSI-X vectors after enabling MSI-X.
> 
> The first part of this work can be found here:
> 
>     https://lore.kernel.org/r/20211126222700.862407977@linutronix.de
> 
> This second part has the following important changes:
> 
>    1) Cleanup of the MSI related data in struct device
> 
>       struct device contains at the moment various MSI related parts. Some
>       of them (the irq domain pointer) cannot be moved out, but the rest
>       can be allocated on first use. This is in preparation of adding more
>       per device MSI data later on.
> 
>    2) Consolidation of sysfs handling
> 
>       As a first step this moves the sysfs pointer from struct msi_desc
>       into the new per device MSI data structure where it belongs.
> 
>       Later changes will cleanup this code further, but that's not possible
>       at this point.
> 
>    3) Store per device properties in the per device MSI data to avoid
>       looking up MSI descriptors and analysing their data. Cleanup all
>       related use cases.
> 
>    4) Provide a function to retrieve the Linux interrupt number for a given
>       MSI index similar to pci_irq_vector() and cleanup all open coded
>       variants.

The msi_get_virq() sure does make a big difference.. Though it does
highlight there is some asymmetry with how platform and PCI works here
where PCI fills some 'struct msix_entry *'. Many drivers would be
quite happy to just call msi_get_virq() and avoid the extra memory, so
I think the msi_get_virq() version is good.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Thanks,
Jason