Messages in this thread |  | | Subject | Re: [PATCH] dma-mapping: Reduce dma_mapping_error() inline bloat | From | Marek Szyprowski <> | Date | Tue, 01 Aug 2017 09:58:07 +0200 |
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Hi Robin,
On 2017-07-24 19:29, Robin Murphy wrote: > Thanks to the nested inlining, all drivers correctly calling > dma_mapping_error() after a mapping a page or single buffer generate two > calls to get_arch_dma_ops() per callsite, which all adds up to a fair > old chunk of useless code, e.g. ~3KB for an arm64 defconfig plus extras: > > text data bss dec hex filename > 13051391 1503898 327768 14883057 e318f1 vmlinux.o.old > 13050751 1503898 327768 14882417 e31671 vmlinux.o.new > > Give the compiler a hand by making it clear we want the same ops.
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com>
Similar pattern is used in drivers/xen/swiotlb-xen.c for mmap and get_sgtable. This could be also fixed, although those are not used so frequently as dma_mapping_error.
> Signed-off-by: Robin Murphy <robin.murphy@arm.com> > --- > include/linux/dma-mapping.h | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h > index 843ab866e0f4..239e53d12ee8 100644 > --- a/include/linux/dma-mapping.h > +++ b/include/linux/dma-mapping.h > @@ -541,10 +541,11 @@ static inline void dma_free_noncoherent(struct device *dev, size_t size, > > static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr) > { > - debug_dma_mapping_error(dev, dma_addr); > + const struct dma_map_ops *ops = get_dma_ops(dev); > > - if (get_dma_ops(dev)->mapping_error) > - return get_dma_ops(dev)->mapping_error(dev, dma_addr); > + debug_dma_mapping_error(dev, dma_addr); > + if (ops->mapping_error) > + return ops->mapping_error(dev, dma_addr); > return 0; > } >
Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
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