From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robin Murphy Subject: Re: [PATCH] kernel/dma: export dma_alloc_from_contiguous to modules Date: Thu, 11 Jul 2019 09:50:58 +0100 Message-ID: <7d14b94f-454f-d512-bc8f-589f71bc07ea@arm.com> References: <20190711053343.28873-1-miles.chen@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190711053343.28873-1-miles.chen@mediatek.com> Content-Language: en-GB Sender: linux-kernel-owner@vger.kernel.org To: miles.chen@mediatek.com, Christoph Hellwig , Marek Szyprowski Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, wsd_upstream@mediatek.com, linux-mediatek@lists.infradead.org List-Id: linux-mediatek@lists.infradead.org On 11/07/2019 06:33, miles.chen@mediatek.com wrote: > From: Miles Chen > > This change exports dma_alloc_from_contiguous and > dma_release_from_contiguous to modules. > > Currently, we can add a reserve a memory node in dts files, make > it a CMA memory by setting compatible = "shared-dma-pool", > and setup the dev->cma_area by using of_reserved_mem_device_init_by_idx(). > > Export dma_alloc_from_contiguous and dma_release_from_contiguous, so we > can allocate/free from/to dev->cma_area in kernel modules. As far as I understand, this was never intended for drivers to call directly. If a device has its own private CMA area, then regular dma_alloc_attrs() should allocate from that automatically; if that's not happening already, then there's a bug somewhere. Robin. > Signed-off-by: Miles Chen > --- > kernel/dma/contiguous.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c > index b2a87905846d..d5920bdedc77 100644 > --- a/kernel/dma/contiguous.c > +++ b/kernel/dma/contiguous.c > @@ -197,6 +197,7 @@ struct page *dma_alloc_from_contiguous(struct device *dev, size_t count, > > return cma_alloc(dev_get_cma_area(dev), count, align, no_warn); > } > +EXPORT_SYMBOL_GPL(dma_alloc_from_contiguous); > > /** > * dma_release_from_contiguous() - release allocated pages > @@ -213,6 +214,7 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages, > { > return cma_release(dev_get_cma_area(dev), pages, count); > } > +EXPORT_SYMBOL_GPL(dma_release_from_contiguous); > > /* > * Support for reserved memory regions defined in device tree >