Drivers which may pass hotplug policy down to DAX need MMOP_ symbols and the mhp_get_default_online_type function for hotplug use cases.
Some drivers (cxl) co-mingle their hotplug and devdax use-cases into the same driver code, and chose the dax_kmem path as the default driver path - making it difficult to require hotplug as a predicate to building the overall driver (it may break other non-hotplug use-cases). Export mhp_get_default_online_type function to allow these drivers to build when hotplug is disabled and still use the DAX use case. In the built-out case we simply return MMOP_OFFLINE as it's non-destructive. The internal function can never return -1 either, so we choose this to allow for defining the function with 'enum mmop'. Signed-off-by: Gregory Price <[email protected]> --- include/linux/memory_hotplug.h | 29 +++++++++++++++++++++++++++++ mm/memory_hotplug.c | 1 + 2 files changed, 30 insertions(+) diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index e77ef3d7ff73..a8bcb36f93b8 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -6,6 +6,7 @@ #include <linux/spinlock.h> #include <linux/notifier.h> #include <linux/bug.h> +#include <linux/errno.h> struct page; struct zone; @@ -28,6 +29,27 @@ enum mmop { MMOP_ONLINE_MOVABLE, }; +/** + * mmop_to_str - convert memory online type to string + * @online_type: the MMOP_* value to convert + * + * Returns a string representation of the memory online type, + * suitable for sysfs output (includes trailing newline). + */ +static inline const char *mmop_to_str(enum mmop online_type) +{ + switch (online_type) { + case MMOP_ONLINE: + return "online\n"; + case MMOP_ONLINE_KERNEL: + return "online_kernel\n"; + case MMOP_ONLINE_MOVABLE: + return "online_movable\n"; + default: + return "offline\n"; + } +} + #ifdef CONFIG_MEMORY_HOTPLUG struct page *pfn_to_online_page(unsigned long pfn); @@ -221,6 +243,11 @@ static inline bool mhp_supports_memmap_on_memory(void) static inline void pgdat_kswapd_lock(pg_data_t *pgdat) {} static inline void pgdat_kswapd_unlock(pg_data_t *pgdat) {} static inline void pgdat_kswapd_lock_init(pg_data_t *pgdat) {} + +static inline int mhp_online_type_from_str(const char *str) +{ + return -EOPNOTSUPP; +} #endif /* ! CONFIG_MEMORY_HOTPLUG */ /* @@ -316,6 +343,8 @@ extern struct zone *zone_for_pfn_range(enum mmop online_type, extern int arch_create_linear_mapping(int nid, u64 start, u64 size, struct mhp_params *params); void arch_remove_linear_mapping(u64 start, u64 size); +#else +static inline enum mmop mhp_get_default_online_type(void) { return MMOP_OFFLINE; } #endif /* CONFIG_MEMORY_HOTPLUG */ #endif /* __LINUX_MEMORY_HOTPLUG_H */ diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 282bf3d89613..af9a6cb5a2f9 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -240,6 +240,7 @@ enum mmop mhp_get_default_online_type(void) return mhp_default_online_type; } +EXPORT_SYMBOL_GPL(mhp_get_default_online_type); void mhp_set_default_online_type(enum mmop online_type) { -- 2.53.0
