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 <pratyush@kernel.org>
Suggested-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/kexec_handover.h b/include/linux/kexec_handover.h
index a56ff3ffaf176d563af00e66ed45dfc0f5e6edc3..ac4129d1d7416d570baa480dbe8a0190a176824d 100644 (file)
--- 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 e44fd7ceff2ec60a0cc017e0eec28517cf45b8a8..56cc1aad5c5c31d2b5f9d8d27f0e6128f294aeef 100644 (file)
--- 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);