From: Christoph Hellwig <hch@lst.de>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: laurentiu.tudor@nxp.com, hch@lst.de, stern@rowland.harvard.edu,
linux-usb@vger.kernel.org, marex@denx.de, leoyang.li@nxp.com,
linux-kernel@vger.kernel.org, robin.murphy@arm.com,
noring@nocrew.org, JuergenUrban@gmx.de
Subject: Re: [PATCH v4 1/3] USB: use genalloc for USB HCs with local memory
Date: Tue, 21 May 2019 12:28:35 +0200 [thread overview]
Message-ID: <20190521102835.GA1973@lst.de> (raw)
In-Reply-To: <20190521081657.GA10639@kroah.com>
On Tue, May 21, 2019 at 10:16:57AM +0200, Greg KH wrote:
> > + if (hcd->driver->flags & HCD_LOCAL_MEM)
> > + return gen_pool_dma_alloc(hcd->localmem_pool, size, dma);
>
> Does this patch now break things? hcd->localmem_pool at this point in
> time is NULL, so this call will fail. There's no chance for any host
> controller driver to actually set up this pool in this patch, so is
> bisection broken?
>
> I think you fix this up in later patches, right?
>
> And if so, why do we even need HCD_LOCAL_MEM anymore? Can't we just
> test for the presence of hcd->localmem_pool in order to determine which
> allocation method to use?
True. And that also sound like a good bisectability strategy:
- first add hcd->localmem_pool and test for it
- convert drivers over to it
- remove HCD_LOCAL_MEM
next prev parent reply other threads:[~2019-05-21 10:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-16 11:47 [PATCH v4 0/3] prerequisites for device reserved local mem rework laurentiu.tudor
2019-05-16 11:47 ` [PATCH v4 1/3] USB: use genalloc for USB HCs with local memory laurentiu.tudor
2019-05-21 8:16 ` Greg KH
2019-05-21 10:28 ` Christoph Hellwig [this message]
2019-05-21 11:04 ` Laurentiu Tudor
2019-05-21 11:15 ` Greg KH
2019-05-16 11:47 ` [PATCH v4 2/3] usb: host: ohci-sm501: init genalloc for " laurentiu.tudor
2019-05-21 10:39 ` Christoph Hellwig
2019-05-21 11:08 ` Laurentiu Tudor
2019-05-16 11:47 ` [PATCH v4 3/3] usb: host: ohci-tmio: " laurentiu.tudor
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