From: Christoph Hellwig <hch@lst.de>
To: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>,
Thomas Gleixner <tglx@linutronix.de>,
Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-pci@vger.kernel.org,
Linux Kernel Mailinglist <linux-kernel@vger.kernel.org>,
Hannes Reinecke <hare@suse.com>
Subject: Re: [RFC PATCH] pci: add pci_irq_get_affinity_vector()
Date: Tue, 8 Nov 2016 16:11:50 +0100 [thread overview]
Message-ID: <20161108151150.GA14002@lst.de> (raw)
In-Reply-To: <40d6e3d4-7e63-0d23-3e5c-a877cebd539a@suse.de>
On Tue, Nov 08, 2016 at 04:08:51PM +0100, Hannes Reinecke wrote:
> The use-case here is that one needs to feed the MSI-X index into the driver
> command structure. While we can extract that number trivially with scsi-mq,
> but for scsi-sq we don't have such means.
> The main impetus of this RFC is to figure out if such a function would have
> a chance of getting upstream, or if I have to continue use cpumaps in the
> drivers.
There should be no need for a cpumap, nor should there be any need
for a lookup. Driver will need the vector index for some admin ops,
but it can store it in it's driver-private queue structure (e.g. take
a look at the cq_vector field in NVMe). Drivers really should not need
this during I/O, but if for some weird reason they do that driver specific
field is trivially reachable through the hw_ctx which gets passed to
->queue_rq.
next prev parent reply other threads:[~2016-11-08 15:11 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-08 7:47 [RFC PATCH] pci: add pci_irq_get_affinity_vector() Hannes Reinecke
2016-11-08 14:48 ` Thomas Gleixner
2016-11-08 14:56 ` Christoph Hellwig
2016-11-08 15:08 ` Hannes Reinecke
2016-11-08 15:11 ` Christoph Hellwig [this message]
2016-11-08 15:20 ` Hannes Reinecke
2016-11-08 15:25 ` Christoph Hellwig
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