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From: Chris Leech <cleech@redhat.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christoph Hellwig <hch@lst.de>, Rasesh Mody <rmody@marvell.com>,
	Ariel Elior <aelior@marvell.com>,
	Sudarsana Kalluru <skalluru@marvell.com>,
	Manish Chopra <manishc@marvell.com>,
	Nilesh Javali <njavali@marvell.com>,
	Manish Rangankar <mrangankar@marvell.com>,
	Jerry Snitselaar <jsnitsel@redhat.com>,
	John Meneghini <jmeneghi@redhat.com>,
	Lee Duncan <lduncan@suse.com>,
	Mike Christie <michael.christie@oracle.com>,
	Hannes Reinecke <hare@kernel.org>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] cnic,bnx2,bnx2x: use UIO_MEM_DMA_COHERENT
Date: Sat, 30 Sep 2023 11:19:20 -0700	[thread overview]
Message-ID: <ZRhmqBRNUB3AfLv/@rhel-developer-toolbox> (raw)
In-Reply-To: <2023093055-gotten-astronomy-a98b@gregkh>

On Sat, Sep 30, 2023 at 09:06:51AM +0200, Greg Kroah-Hartman wrote:
> On Fri, Sep 29, 2023 at 10:00:23AM -0700, Chris Leech wrote:
> > Make use of the new UIO_MEM_DMA_COHERENT type to properly handle mmap
> > for dma_alloc_coherent buffers.
> 
> Why are ethernet drivers messing around with UIO devices?  That's not
> what UIO is for, unless you are trying to do kernel bypass for these
> devices without anyone noticing?
> 
> confused,

It's confusing. The bnx2 driver stack included a cnic (converged nic?)
module that sits between the ethernet drivers (bnx2, bnx2x) and protocol
offload drivers (iscsi, fcoe, rdma).

The iscsi module (bnx2i) uses a passthrough interface from cnic to
handle some network configuration that the device firmware doesn't do.
It uses a uio device and a userspace component called iscsiuio to do
that.

Questions beyond that will probably need to be answer by one of the many
Marvell engineers copied on this thread.

- Chris


  parent reply	other threads:[~2023-09-30 18:19 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-29 17:00 [PATCH 0/3] UIO_MEM_DMA_COHERENT for cnic/bnx2/bnx2x Chris Leech
2023-09-29 17:00 ` [PATCH 1/3] uio: introduce UIO_DMA_COHERENT type Chris Leech
2023-09-30  7:10   ` Greg Kroah-Hartman
2023-09-30 18:08     ` Chris Leech
2023-10-02  6:09   ` Christoph Hellwig
2023-09-29 17:00 ` [PATCH 2/3] cnic,bnx2,bnx2x: page align uio mmap allocations Chris Leech
2023-09-29 17:18   ` Jacob Keller
2023-10-02  6:11   ` Christoph Hellwig
2023-09-29 17:00 ` [PATCH 3/3] cnic,bnx2,bnx2x: use UIO_MEM_DMA_COHERENT Chris Leech
2023-09-29 17:19   ` Jacob Keller
2023-09-30  7:06   ` Greg Kroah-Hartman
2023-09-30  9:10     ` Jerry Snitselaar
2023-09-30 18:29       ` Greg Kroah-Hartman
2023-09-30 18:19     ` Chris Leech [this message]
2023-09-30 18:28       ` Greg Kroah-Hartman
2023-10-01 10:44         ` Hannes Reinecke
2023-10-01 11:57           ` Greg Kroah-Hartman
2023-10-01 14:22             ` Jerry Snitselaar
2023-10-02  6:04               ` Christoph Hellwig
2023-10-02  7:50                 ` Jerry Snitselaar
2023-10-02  8:46                   ` Greg Kroah-Hartman
2023-10-02  8:59                     ` Hannes Reinecke
2023-10-05 10:39                       ` Paolo Abeni

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