From: Douglas Anderson Date: Mon, 6 Apr 2026 23:22:57 +0000 (-0700) Subject: driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync() X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=d99167df047a12cac636188f994a9e8f1f9779ab;p=thirdparty%2Fkernel%2Flinux.git driver core: Replace dev->dma_skip_sync with dev_dma_skip_sync() In C, bitfields are not necessarily safe to modify from multiple threads without locking. Switch "dma_skip_sync" over to the "flags" field so modifications are safe. Cc: Alexander Lobakin Cc: Eric Dumazet Cc: Christoph Hellwig Reviewed-by: Rafael J. Wysocki (Intel) Reviewed-by: Danilo Krummrich Acked-by: Greg Kroah-Hartman Acked-by: Marek Szyprowski Signed-off-by: Douglas Anderson Link: https://patch.msgid.link/20260406162231.v5.4.Icf072aa4184dd86a88fa8ca195b09d1651984000@changeid Signed-off-by: Danilo Krummrich --- diff --git a/include/linux/device.h b/include/linux/device.h index bb02afb00f05e..cc93a5e1e5d23 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -517,12 +517,15 @@ struct device_physical_location { * until other devices probe successfully. * @DEV_FLAG_DMA_IOMMU: Device is using default IOMMU implementation for DMA and * doesn't rely on dma_ops structure. + * @DEV_FLAG_DMA_SKIP_SYNC: DMA sync operations can be skipped for coherent + * buffers. * @DEV_FLAG_COUNT: Number of defined struct_device_flags. */ enum struct_device_flags { DEV_FLAG_READY_TO_PROBE = 0, DEV_FLAG_CAN_MATCH = 1, DEV_FLAG_DMA_IOMMU = 2, + DEV_FLAG_DMA_SKIP_SYNC = 3, DEV_FLAG_COUNT }; @@ -616,7 +619,6 @@ enum struct_device_flags { * and optionall (if the coherent mask is large enough) also * for dma allocations. This flag is managed by the dma ops * instance from ->dma_supported. - * @dma_skip_sync: DMA sync operations can be skipped for coherent buffers. * @flags: DEV_FLAG_XXX flags. Use atomic bitfield operations to modify. * * At the lowest level, every device in a Linux system is represented by an @@ -733,9 +735,6 @@ struct device { #ifdef CONFIG_DMA_OPS_BYPASS bool dma_ops_bypass : 1; #endif -#ifdef CONFIG_DMA_NEED_SYNC - bool dma_skip_sync:1; -#endif DECLARE_BITMAP(flags, DEV_FLAG_COUNT); }; @@ -765,6 +764,7 @@ static inline bool dev_test_and_set_##accessor_name(struct device *dev) \ __create_dev_flag_accessors(ready_to_probe, DEV_FLAG_READY_TO_PROBE); __create_dev_flag_accessors(can_match, DEV_FLAG_CAN_MATCH); __create_dev_flag_accessors(dma_iommu, DEV_FLAG_DMA_IOMMU); +__create_dev_flag_accessors(dma_skip_sync, DEV_FLAG_DMA_SKIP_SYNC); #undef __create_dev_flag_accessors diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h index 6a1832a73cad8..9e677a79f3a8f 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -240,8 +240,8 @@ static inline void dma_reset_need_sync(struct device *dev) { #ifdef CONFIG_DMA_NEED_SYNC /* Reset it only once so that the function can be called on hotpath */ - if (unlikely(dev->dma_skip_sync)) - dev->dma_skip_sync = false; + if (unlikely(dev_dma_skip_sync(dev))) + dev_clear_dma_skip_sync(dev); #endif } diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index db8ab24a54f4a..cc0823a99cfdb 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -429,7 +429,7 @@ bool __dma_need_sync(struct device *dev, dma_addr_t dma_addr); static inline bool dma_dev_need_sync(const struct device *dev) { /* Always call DMA sync operations when debugging is enabled */ - return !dev->dma_skip_sync || IS_ENABLED(CONFIG_DMA_API_DEBUG); + return !dev_dma_skip_sync(dev) || IS_ENABLED(CONFIG_DMA_API_DEBUG); } static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 23ed8eb9233e5..a81a316971ff4 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -476,7 +476,7 @@ bool dma_need_unmap(struct device *dev) { if (!dma_map_direct(dev, get_dma_ops(dev))) return true; - if (!dev->dma_skip_sync) + if (!dev_dma_skip_sync(dev)) return true; return IS_ENABLED(CONFIG_DMA_API_DEBUG); } @@ -492,16 +492,16 @@ static void dma_setup_need_sync(struct device *dev) * mapping, if any. During the device initialization, it's * enough to check only for the DMA coherence. */ - dev->dma_skip_sync = dev_is_dma_coherent(dev); + dev_assign_dma_skip_sync(dev, dev_is_dma_coherent(dev)); else if (!ops->sync_single_for_device && !ops->sync_single_for_cpu && !ops->sync_sg_for_device && !ops->sync_sg_for_cpu) /* * Synchronization is not possible when none of DMA sync ops * is set. */ - dev->dma_skip_sync = true; + dev_set_dma_skip_sync(dev); else - dev->dma_skip_sync = false; + dev_clear_dma_skip_sync(dev); } #else /* !CONFIG_DMA_NEED_SYNC */ static inline void dma_setup_need_sync(struct device *dev) { } diff --git a/mm/hmm.c b/mm/hmm.c index 5955f2f0c83db..c72c9ddfdb2f6 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -709,7 +709,7 @@ int hmm_dma_map_alloc(struct device *dev, struct hmm_dma_map *map, * best approximation to ensure no swiotlb buffering happens. */ #ifdef CONFIG_DMA_NEED_SYNC - dma_need_sync = !dev->dma_skip_sync; + dma_need_sync = !dev_dma_skip_sync(dev); #endif /* CONFIG_DMA_NEED_SYNC */ if (dma_need_sync || dma_addressing_limited(dev)) return -EOPNOTSUPP;