From 840fe43d371fc59ef2da6b6bb88a4d480eed9a38 Mon Sep 17 00:00:00 2001 From: Pratyush Yadav Date: Fri, 16 Jan 2026 11:22:14 +0000 Subject: [PATCH] kho: use unsigned long for nr_pages Patch series "kho: clean up page initialization logic", v2. This series simplifies the page initialization logic in kho_restore_page(). It was originally only a single patch [0], but on Pasha's suggestion, I added another patch to use unsigned long for nr_pages. Technically speaking, the patches aren't related and can be applied independently, but bundling them together since patch 2 relies on 1 and it is easier to manage them this way. This patch (of 2): With 4k pages, a 32-bit nr_pages can span up to 16 TiB. While it is a lot, there exist systems with terabytes of RAM. gup is also moving to using long for nr_pages. Use unsigned long and make KHO future-proof. Link: https://lkml.kernel.org/r/20260116112217.915803-1-pratyush@kernel.org Link: https://lkml.kernel.org/r/20260116112217.915803-2-pratyush@kernel.org Signed-off-by: Pratyush Yadav Suggested-by: Pasha Tatashin Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Pasha Tatashin Cc: Alexander Graf Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton --- include/linux/kexec_handover.h | 6 +++--- kernel/liveupdate/kexec_handover.c | 11 ++++++----- 2 files changed, 9 insertions(+), 8 deletions(-) diff --git a/include/linux/kexec_handover.h b/include/linux/kexec_handover.h index a56ff3ffaf176..ac4129d1d7416 100644 --- a/include/linux/kexec_handover.h +++ b/include/linux/kexec_handover.h @@ -22,15 +22,15 @@ bool is_kho_boot(void); int kho_preserve_folio(struct folio *folio); void kho_unpreserve_folio(struct folio *folio); -int kho_preserve_pages(struct page *page, unsigned int nr_pages); -void kho_unpreserve_pages(struct page *page, unsigned int nr_pages); +int kho_preserve_pages(struct page *page, unsigned long nr_pages); +void kho_unpreserve_pages(struct page *page, unsigned long nr_pages); int kho_preserve_vmalloc(void *ptr, struct kho_vmalloc *preservation); void kho_unpreserve_vmalloc(struct kho_vmalloc *preservation); void *kho_alloc_preserve(size_t size); void kho_unpreserve_free(void *mem); void kho_restore_free(void *mem); struct folio *kho_restore_folio(phys_addr_t phys); -struct page *kho_restore_pages(phys_addr_t phys, unsigned int nr_pages); +struct page *kho_restore_pages(phys_addr_t phys, unsigned long nr_pages); void *kho_restore_vmalloc(const struct kho_vmalloc *preservation); int kho_add_subtree(const char *name, void *fdt); void kho_remove_subtree(void *fdt); diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c index e44fd7ceff2ec..56cc1aad5c5c3 100644 --- a/kernel/liveupdate/kexec_handover.c +++ b/kernel/liveupdate/kexec_handover.c @@ -219,7 +219,8 @@ static int __kho_preserve_order(struct kho_mem_track *track, unsigned long pfn, static struct page *kho_restore_page(phys_addr_t phys, bool is_folio) { struct page *page = pfn_to_online_page(PHYS_PFN(phys)); - unsigned int nr_pages, ref_cnt; + unsigned long nr_pages; + unsigned int ref_cnt; union kho_page_info info; if (!page) @@ -246,7 +247,7 @@ static struct page *kho_restore_page(phys_addr_t phys, bool is_folio) * count of 1 */ ref_cnt = is_folio ? 0 : 1; - for (unsigned int i = 1; i < nr_pages; i++) + for (unsigned long i = 1; i < nr_pages; i++) set_page_count(page + i, ref_cnt); if (is_folio && info.order) @@ -288,7 +289,7 @@ EXPORT_SYMBOL_GPL(kho_restore_folio); * * Return: 0 on success, error code on failure */ -struct page *kho_restore_pages(phys_addr_t phys, unsigned int nr_pages) +struct page *kho_restore_pages(phys_addr_t phys, unsigned long nr_pages) { const unsigned long start_pfn = PHYS_PFN(phys); const unsigned long end_pfn = start_pfn + nr_pages; @@ -837,7 +838,7 @@ EXPORT_SYMBOL_GPL(kho_unpreserve_folio); * * Return: 0 on success, error code on failure */ -int kho_preserve_pages(struct page *page, unsigned int nr_pages) +int kho_preserve_pages(struct page *page, unsigned long nr_pages) { struct kho_mem_track *track = &kho_out.track; const unsigned long start_pfn = page_to_pfn(page); @@ -881,7 +882,7 @@ EXPORT_SYMBOL_GPL(kho_preserve_pages); * kho_preserve_pages() call. Unpreserving arbitrary sub-ranges of larger * preserved blocks is not supported. */ -void kho_unpreserve_pages(struct page *page, unsigned int nr_pages) +void kho_unpreserve_pages(struct page *page, unsigned long nr_pages) { struct kho_mem_track *track = &kho_out.track; const unsigned long start_pfn = page_to_pfn(page); -- 2.47.3