Hi, On Thu, May 22, 2025 at 12:14:18PM -0700, Jared Kangas wrote: > The CMA heap's name in devtmpfs can vary depending on how the heap is > defined. Its name defaults to "reserved", but if a CMA area is defined > in the devicetree, the heap takes on the devicetree node's name, such as > "default-pool" or "linux,cma". To simplify naming, unconditionally name > it "default_cma_region", but keep a legacy node in place backed by the > same underlying allocator for backwards compatibility. > > Signed-off-by: Jared Kangas <jkan...@redhat.com> > --- > Documentation/userspace-api/dma-buf-heaps.rst | 7 +++++-- > drivers/dma-buf/heaps/Kconfig | 10 ++++++++++ > drivers/dma-buf/heaps/cma_heap.c | 20 ++++++++++++++++++- > 3 files changed, 34 insertions(+), 3 deletions(-) > > diff --git a/Documentation/userspace-api/dma-buf-heaps.rst > b/Documentation/userspace-api/dma-buf-heaps.rst > index 23bd0bd7b0654..1dfe5e7acd5a3 100644 > --- a/Documentation/userspace-api/dma-buf-heaps.rst > +++ b/Documentation/userspace-api/dma-buf-heaps.rst > @@ -21,5 +21,8 @@ following heaps: > usually created either through the kernel commandline through the > ``cma`` parameter, a memory region Device-Tree node with the > ``linux,cma-default`` property set, or through the ``CMA_SIZE_MBYTES`` or > - ``CMA_SIZE_PERCENTAGE`` Kconfig options. Depending on the platform, it > - might be called ``reserved``, ``linux,cma``, or ``default-pool``. > + ``CMA_SIZE_PERCENTAGE`` Kconfig options. The heap's name in devtmpfs is > + ``default_cma_region``. For backwards compatibility, when the > + ``DMABUF_HEAPS_CMA_LEGACY`` Kconfig option is set, a duplicate node is > + created following legacy naming conventions; the legacy name might be > + ``reserved``, ``linux,cma``, or ``default-pool``. > diff --git a/drivers/dma-buf/heaps/Kconfig b/drivers/dma-buf/heaps/Kconfig > index a5eef06c42264..bb369b38b001a 100644 > --- a/drivers/dma-buf/heaps/Kconfig > +++ b/drivers/dma-buf/heaps/Kconfig > @@ -12,3 +12,13 @@ config DMABUF_HEAPS_CMA > Choose this option to enable dma-buf CMA heap. This heap is backed > by the Contiguous Memory Allocator (CMA). If your system has these > regions, you should say Y here. > + > +config DMABUF_HEAPS_CMA_LEGACY > + bool "Legacy DMA-BUF CMA Heap" > + default y > + depends on DMABUF_HEAPS_CMA > + help > + Add a duplicate CMA-backed dma-buf heap with legacy naming derived > + from the CMA area's devicetree node, or "reserved" if the area is not > + defined in the devicetree. This uses the same underlying allocator as > + CONFIG_DMABUF_HEAPS_CMA. > diff --git a/drivers/dma-buf/heaps/cma_heap.c > b/drivers/dma-buf/heaps/cma_heap.c > index e998d8ccd1dc6..dfeccafc6ae3c 100644 > --- a/drivers/dma-buf/heaps/cma_heap.c > +++ b/drivers/dma-buf/heaps/cma_heap.c > @@ -9,6 +9,9 @@ > * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/ > * Andrew F. Davis <a...@ti.com> > */ > + > +#define pr_fmt(fmt) "cma_heap: " fmt > + > #include <linux/cma.h> > #include <linux/dma-buf.h> > #include <linux/dma-heap.h> > @@ -22,6 +25,7 @@ > #include <linux/slab.h> > #include <linux/vmalloc.h> > > +#define DEFAULT_CMA_NAME "default_cma_region" > > struct cma_heap { > struct dma_heap *heap; > @@ -394,15 +398,29 @@ static int __init __add_cma_heap(struct cma *cma, const > char *name) > static int __init add_default_cma_heap(void) > { > struct cma *default_cma = dev_get_cma_area(NULL); > + const char *legacy_cma_name; > int ret; > > if (!default_cma) > return 0; > > - ret = __add_cma_heap(default_cma, cma_get_name(default_cma)); > + ret = __add_cma_heap(default_cma, DEFAULT_CMA_NAME); > if (ret) > return ret; > > + if (IS_ENABLED(CONFIG_DMABUF_HEAPS_CMA_LEGACY)) { > + legacy_cma_name = cma_get_name(default_cma); > + if (!strcmp(legacy_cma_name, DEFAULT_CMA_NAME)) { > + pr_warn("legacy name and default name are the same, > skipping legacy heap\n"); > + return 0; > + } > + > + ret = __add_cma_heap(default_cma, legacy_cma_name); > + if (ret) > + pr_warn("failed to add legacy heap: %pe\n", > + ERR_PTR(-ret));
Are you sure about the -ret? ret should already be a negative number if it failed? With that fixed, Reviewed-by: Maxime Ripard <mrip...@kernel.org> Maxime
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