Commit 840fe43d authored by Pratyush Yadav's avatar Pratyush Yadav Committed by Andrew Morton
Browse files

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: default avatarPratyush Yadav <pratyush@kernel.org>
Suggested-by: default avatarPasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: default avatarMike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: default avatarPasha Tatashin <pasha.tatashin@soleen.com>
Cc: Alexander Graf <graf@amazon.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 931d5c36

include/linux/kexec_handover.h

+3 −3
Original line number Diff line number Diff line
@@ -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);

kernel/liveupdate/kexec_handover.c

+6 −5
Original line number Diff line number Diff line
@@ -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);