From: Jason Gunthorpe <jgg@nvidia.com>
To: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@infradead.org>,
Leon Romanovsky <leon@kernel.org>,
Doug Ledford <dledford@redhat.com>,
Adit Ranadive <aditr@vmware.com>,
"Ariel Elior" <aelior@marvell.com>,
Bernard Metzler <bmt@zurich.ibm.com>,
"Christian Benvenuti" <benve@cisco.com>,
Dennis Dalessandro <dennis.dalessandro@intel.com>,
Devesh Sharma <devesh.sharma@broadcom.com>,
Faisal Latif <faisal.latif@intel.com>,
Gal Pressman <galpress@amazon.com>, Lijun Ou <oulijun@huawei.com>,
<linux-rdma@vger.kernel.org>,
Michal Kalderon <mkalderon@marvell.com>,
Mike Marciniszyn <mike.marciniszyn@intel.com>,
Naresh Kumar PBS <nareshkumar.pbs@broadcom.com>,
Nelson Escobar <neescoba@cisco.com>,
Parav Pandit <parav@nvidia.com>,
Parvi Kaustubhi <pkaustub@cisco.com>,
Potnuri Bharat Teja <bharat@chelsio.com>,
Selvin Xavier <selvin.xavier@broadcom.com>,
Shiraz Saleem <shiraz.saleem@intel.com>,
Somnath Kotur <somnath.kotur@broadcom.com>,
Sriharsha Basavapatna <sriharsha.basavapatna@broadcom.com>,
VMware PV-Drivers <pv-drivers@vmware.com>,
Weihang Li <liweihang@huawei.com>,
"Wei Hu(Xavier)" <huwei87@hisilicon.com>,
Yishai Hadas <yishaih@nvidia.com>,
Zhu Yanjun <yanjunz@nvidia.com>
Subject: Re: [PATCH rdma-next] RDMA: Explicitly pass in the dma_device to ib_register_device
Date: Tue, 6 Oct 2020 13:53:46 -0300 [thread overview]
Message-ID: <20201006165346.GK4734@nvidia.com> (raw)
In-Reply-To: <f20a4639-7674-8d2c-66dc-ebc028b14ef0@acm.org>
On Tue, Oct 06, 2020 at 07:29:16AM -0700, Bart Van Assche wrote:
> On 9/24/20 4:49 AM, Jason Gunthorpe wrote:
> > On Thu, Sep 24, 2020 at 06:49:07AM +0100, Christoph Hellwig wrote:
> > > > > > + } else {
> > > > > > + device->dev.dma_parms = dma_device->dma_parms;
> > > > > > /*
> > > > > > + * Auto setup the segment size if a DMA device was passed in.
> > > > > > + * The PCI core sets the maximum segment size to 64 KB. Increase
> > > > > > + * this parameter to 2 GB.
> > > > > > */
> > > > > > + dma_set_max_seg_size(dma_device, SZ_2G);
> > > > >
> > > > > You can't just inherity DMA properties like this this. Please
> > > > > fix all code that looks at the seg size to look at the DMA device.
> > > >
> > > > Inherit? This is overriding the PCI default of 64K to be 2G for RDMA
> > > > devices.
> > >
> > > With inherit I mean the
> > >
> > > device->dev.dma_parms = dma_device->dma_parms;
> > >
> > > line, which is completely bogus. All DMA mapping is done on the
> > > dma_device in the RDMA core and ULPs, so it also can't have an effect.
> >
> > Oh. Yes, no idea why that is there..
> >
> > commit c9121262d57b8a3be4f08073546436ba0128ca6a
> > Author: Bart Van Assche <bvanassche@acm.org>
> > Date: Fri Oct 25 15:58:30 2019 -0700
> >
> > RDMA/core: Set DMA parameters correctly
> > The dma_set_max_seg_size() call in setup_dma_device() does not have any
> > effect since device->dev.dma_parms is NULL. Fix this by initializing
> > device->dev.dma_parms first.
> >
> > Bart?
>
> (just noticed this email)
>
> Hi Jason,
>
> That code may be a leftover from when the ib_dma_*() functions used &dev->dev as
> their first argument instead of dev->dma_device.
Hmm the above was two years after the commit that added dma_device? I
assumed you added this because you were doing testing with rxe?
Jason
next prev parent reply other threads:[~2020-10-06 16:54 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-22 8:27 [PATCH rdma-next] RDMA: Explicitly pass in the dma_device to ib_register_device Leon Romanovsky
2020-09-22 8:58 ` Bernard Metzler
2020-09-22 10:14 ` Leon Romanovsky
2020-09-22 14:22 ` Bernard Metzler
2020-09-22 16:22 ` Jason Gunthorpe
2020-09-23 5:39 ` Christoph Hellwig
2020-09-23 18:35 ` Jason Gunthorpe
2020-09-24 5:53 ` Christoph Hellwig
2020-09-24 6:13 ` Christoph Hellwig
2020-09-24 11:55 ` Jason Gunthorpe
2020-09-24 7:31 ` Parav Pandit
2020-09-23 5:38 ` Christoph Hellwig
2020-09-23 6:45 ` Leon Romanovsky
2020-09-23 6:54 ` Christoph Hellwig
2020-09-23 7:10 ` Leon Romanovsky
2020-09-23 7:21 ` Christoph Hellwig
2020-09-23 18:34 ` Jason Gunthorpe
2020-09-24 5:49 ` Christoph Hellwig
2020-09-24 11:49 ` Jason Gunthorpe
2020-10-06 14:29 ` Bart Van Assche
2020-10-06 16:53 ` Jason Gunthorpe [this message]
2020-10-06 18:22 ` Bart Van Assche
2020-10-06 18:39 ` Jason Gunthorpe
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