On Thu, Feb 26, 2026 at 08:58:51AM -0800, T.J. Mercier wrote: > On Thu, Feb 26, 2026 at 2:38 AM Maxime Ripard <[email protected]> wrote: > > > > Hi David, > > > > On Thu, Feb 26, 2026 at 11:25:24AM +0100, David Hildenbrand (Arm) wrote: > > > On 2/25/26 17:41, Maxime Ripard wrote: > > > > The CMA dma-buf heap uses cma_alloc() and cma_release() to allocate and > > > > free, respectively, its CMA buffers. > > > > > > > > However, these functions are not exported. Since we want to turn the CMA > > > > heap into a module, let's export them both. > > > > > > > > Signed-off-by: Maxime Ripard <[email protected]> > > > > --- > > > > mm/cma.c | 2 ++ > > > > 1 file changed, 2 insertions(+) > > > > > > > > diff --git a/mm/cma.c b/mm/cma.c > > > > index > > > > 94b5da468a7d719e5144d33b06bcc7619c0fbcc9..be142b473f3bd41b9c7d8ba4397f018f6993d962 > > > > 100644 > > > > --- a/mm/cma.c > > > > +++ b/mm/cma.c > > > > @@ -949,10 +949,11 @@ struct page *cma_alloc(struct cma *cma, unsigned > > > > long count, > > > > if (page) > > > > set_pages_refcounted(page, count); > > > > > > > > return page; > > > > } > > > > +EXPORT_SYMBOL_GPL(cma_alloc); > > > > > > > > static struct cma_memrange *find_cma_memrange(struct cma *cma, > > > > const struct page *pages, unsigned long count) > > > > { > > > > struct cma_memrange *cmr = NULL; > > > > @@ -1025,10 +1026,11 @@ bool cma_release(struct cma *cma, const struct > > > > page *pages, > > > > > > > > __cma_release_frozen(cma, cmr, pages, count); > > > > > > > > return true; > > > > } > > > > +EXPORT_SYMBOL_GPL(cma_release); > > > > > > > > bool cma_release_frozen(struct cma *cma, const struct page *pages, > > > > unsigned long count) > > > > { > > > > struct cma_memrange *cmr; > > > > > > > > > > I'm wondering whether we want to restrict all these exports to the > > > dma-buf module only using EXPORT_SYMBOL_FOR_MODULES(). > > > > TIL about EXPORT_SYMBOL_FOR_MODULES, thanks. > > Ohh, ditto. > > > > Especially dma_contiguous_default_area() (patch #4), I am not sure > > > whether we want arbitrary modules to mess with that. > > > > Yeah, I wasn't too fond about that one either. Alternatively, I guess we > > could turn dev_get_cma_area into a non-inlined function and export that > > instead? > > I checked the history to see if dev_get_cma_area was converted to > inline at some point for performance, but it has always been that way > since 3.5. That'd be my only worry with un-inlining and exporting it. > EXPORT_SYMBOL_FOR_MODULES sounds like a better way to me.
I just realised the new tegra heap is also going to use cma_alloc: https://lore.kernel.org/dri-devel/[email protected]/ I exported dev_get_cma_area() like we discussed, but kept EXPORT_SYMBOL for now in the new version. Maxime
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