Use a folio for the page cache page the s390 fault handler reads the old kernel's memory into. This removes four compound_head() calls and one of the last callers of find_or_create_page().
The vmcore mapping only has order-0 folios, so the logic is unchanged. Compile tested for s390. Signed-off-by: Tal Zussman <[email protected]> --- This is based on the kexec-next branch of the liveupdate tree. --- fs/proc/vmcore.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 44d15436439f..2dc3803aa11d 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -474,29 +474,30 @@ static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf) pgoff_t index = vmf->pgoff; struct iov_iter iter; struct kvec kvec; - struct page *page; + struct folio *folio; loff_t offset; int rc; - page = find_or_create_page(mapping, index, GFP_KERNEL); - if (!page) + folio = __filemap_get_folio(mapping, index, + FGP_LOCK | FGP_ACCESSED | FGP_CREAT, GFP_KERNEL); + if (IS_ERR(folio)) return VM_FAULT_OOM; - if (!PageUptodate(page)) { - offset = (loff_t) index << PAGE_SHIFT; - kvec.iov_base = page_address(page); - kvec.iov_len = PAGE_SIZE; - iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, PAGE_SIZE); + if (!folio_test_uptodate(folio)) { + offset = folio_pos(folio); + kvec.iov_base = folio_address(folio); + kvec.iov_len = folio_size(folio); + iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, folio_size(folio)); rc = __read_vmcore(&iter, &offset); if (rc < 0) { - unlock_page(page); - put_page(page); + folio_unlock(folio); + folio_put(folio); return vmf_error(rc); } - SetPageUptodate(page); + folio_mark_uptodate(folio); } - unlock_page(page); - vmf->page = page; + folio_unlock(folio); + vmf->page = folio_file_page(folio, index); return 0; #else return VM_FAULT_SIGBUS; --- base-commit: 4d17a004cfd5489f88ad0a7a151dea11a533338b change-id: 20260907-vmcore-fault-folio-4b382eeff262 Best regards, -- Tal Zussman <[email protected]>
