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Date: Thu, 22 Aug 2019 10:11:08 -0700
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: next take at setting up a dma mask by default for platform
 devices v2
Message-ID: <20190822171108.GA17471@kroah.com>
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To: Christoph Hellwig <hch@lst.de>
Cc: Maxime Chevallier <maxime.chevallier@bootlin.com>, Gavin Li <git@thegavinli.com>, Laurentiu Tudor <laurentiu.tudor@nxp.com>, Minas Harutyunyan <hminas@synopsys.com>, Alan Stern <stern@rowland.harvard.edu>, Geoff Levand <geoff@infradead.org>, Michal Simek <michal.simek@xilinx.com>, Shawn Guo <shawnguo@kernel.org>, Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix Kernel Team <kernel@pengutronix.de>, Fabio Estevam <festevam@gmail.com>, NXP Linux Team <linux-imx@nxp.com>, Mathias Nyman <mathias.nyman@intel.com>, Bin Liu <b-liu@ti.com>, linux-arm-kernel@lists.infradead.org, linux-usb@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-m68k@lists.linux-m68k.org, iommu@lists.linux-foundation.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Message-ID: <20190822171108.PMCXOyzJY9h6SycjHgodcpdWg6UgGbzmG-VbRWJyHak@z>

On Fri, Aug 16, 2019 at 08:24:29AM +0200, Christoph Hellwig wrote:
> Hi all,
> 
> this is another attempt to make sure the dma_mask pointer is always
> initialized for platform devices.  Not doing so lead to lots of
> boilerplate code, and makes platform devices different from all our
> major busses like PCI where we always set up a dma_mask.  In the long
> run this should also help to eventually make dma_mask a scalar value
> instead of a pointer and remove even more cruft.
> 
> The bigger blocker for this last time was the fact that the usb
> subsystem uses the presence or lack of a dma_mask to check if the core
> should do dma mapping for the driver, which is highly unusual.  So we
> fix this first.  Note that this has some overlap with the pending
> desire to use the proper dma_mmap_coherent helper for mapping usb
> buffers.  The first two patches have already been queued up by Greg
> and are only included for completeness.

Note to everyone.  The first two patches in this series is already in
5.3-rc5.

I've applied the rest of the series to my usb-next branch (with the 6th
patch landing there later today.)  They are scheduled to be merge to
Linus in 5.4-rc1.

Christoph, thanks so much for these cleanups.

greg k-h