vmem_altmap_free() and vmem_altmap_offset() could be utlized without CONFIG_ZONE_DEVICE enabled. For example, mm/memory_hotplug.c:__add_pages() relies on that. The altmap is no longer restricted to ZONE_DEVICE handling, but instead depends on CONFIG_SPARSEMEM_VMEMMAP.
When CONFIG_SPARSEMEM_VMEMMAP is disabled, these functions are defined as inline stubs, ensuring compatibility with configurations that do not use sparsemem vmemmap. Without it, lkp reported the following:
ld: arch/x86/mm/init_64.o: in function `remove_pagetable': init_64.c:(.meminit.text+0xfc7): undefined reference to `vmem_altmap_free'
Reported-by: kernel test robot lkp@intel.com Closes: https://lore.kernel.org/oe-kbuild-all/202311180545.VeyRXEDq-lkp@intel.com/ Reviewed-by: Gerald Schaefer gerald.schaefer@linux.ibm.com Signed-off-by: Sumanth Korikkar sumanthk@linux.ibm.com --- include/linux/memremap.h | 12 ------------ include/linux/mm.h | 26 ++++++++++++++++++++++++++ mm/memremap.c | 14 +------------- 3 files changed, 27 insertions(+), 25 deletions(-)
diff --git a/include/linux/memremap.h b/include/linux/memremap.h index 1314d9c5f05b..744c830f4b13 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -196,8 +196,6 @@ struct dev_pagemap *get_dev_pagemap(unsigned long pfn, struct dev_pagemap *pgmap); bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn);
-unsigned long vmem_altmap_offset(struct vmem_altmap *altmap); -void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns); unsigned long memremap_compat_align(void); #else static inline void *devm_memremap_pages(struct device *dev, @@ -228,16 +226,6 @@ static inline bool pgmap_pfn_valid(struct dev_pagemap *pgmap, unsigned long pfn) return false; }
-static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) -{ - return 0; -} - -static inline void vmem_altmap_free(struct vmem_altmap *altmap, - unsigned long nr_pfns) -{ -} - /* when memremap_pages() is disabled all archs can remap a single page */ static inline unsigned long memremap_compat_align(void) { diff --git a/include/linux/mm.h b/include/linux/mm.h index bf5d0b1b16f4..f2344fd8acbe 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3786,6 +3786,32 @@ void vmemmap_free(unsigned long start, unsigned long end, struct vmem_altmap *altmap); #endif
+#ifdef CONFIG_SPARSEMEM_VMEMMAP +static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) +{ + /* number of pfns from base where pfn_to_page() is valid */ + if (altmap) + return altmap->reserve + altmap->free; + return 0; +} + +static inline void vmem_altmap_free(struct vmem_altmap *altmap, + unsigned long nr_pfns) +{ + altmap->alloc -= nr_pfns; +} +#else +static inline unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) +{ + return 0; +} + +static inline void vmem_altmap_free(struct vmem_altmap *altmap, + unsigned long nr_pfns) +{ +} +#endif + #define VMEMMAP_RESERVE_NR 2 #ifdef CONFIG_ARCH_WANT_OPTIMIZE_DAX_VMEMMAP static inline bool __vmemmap_can_optimize(struct vmem_altmap *altmap, diff --git a/mm/memremap.c b/mm/memremap.c index bee85560a243..9531faa92a7c 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -7,6 +7,7 @@ #include <linux/memremap.h> #include <linux/pfn_t.h> #include <linux/swap.h> +#include <linux/mm.h> #include <linux/mmzone.h> #include <linux/swapops.h> #include <linux/types.h> @@ -422,19 +423,6 @@ void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap) } EXPORT_SYMBOL_GPL(devm_memunmap_pages);
-unsigned long vmem_altmap_offset(struct vmem_altmap *altmap) -{ - /* number of pfns from base where pfn_to_page() is valid */ - if (altmap) - return altmap->reserve + altmap->free; - return 0; -} - -void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns) -{ - altmap->alloc -= nr_pfns; -} - /** * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn * @pfn: page frame number to lookup page_map