X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=mm%2Fmincore.c;h=f77433c20279d95c2a87ce7117888e63580c8922;hb=01bf0b64579ead8a82e7cfc32ae44bc667e7ad0f;hp=8aca6f7167bbb25f858075c90c64d766fcc1e4c3;hpb=825020c3866e7312947e17a0caa9dd1a5622bafc;p=safe%2Fjmp%2Flinux-2.6 diff --git a/mm/mincore.c b/mm/mincore.c index 8aca6f7..f77433c 100644 --- a/mm/mincore.c +++ b/mm/mincore.c @@ -7,11 +7,14 @@ /* * The mincore() system call. */ -#include #include +#include #include #include #include +#include +#include +#include #include #include @@ -22,14 +25,22 @@ * and is up to date; i.e. that no page-in operation would be required * at this time if an application were to map and access this page. */ -static unsigned char mincore_page(struct vm_area_struct * vma, - unsigned long pgoff) +static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff) { unsigned char present = 0; - struct address_space * as = vma->vm_file->f_mapping; - struct page * page; + struct page *page; - page = find_get_page(as, pgoff); + /* + * When tmpfs swaps out a page from a file, any process mapping that + * file will not get a swp_entry_t in its pte, but rather it is like + * any other file mapping (ie. marked !present and faulted in with + * tmpfs's .fault). So swapped out tmpfs mappings are tested here. + * + * However when tmpfs moves the page from pagecache and into swapcache, + * it is still in core, but the find_get_page below won't find it. + * No big deal, but make a note of it. + */ + page = find_get_page(mapping, pgoff); if (page) { present = PageUptodate(page); page_cache_release(page); @@ -45,7 +56,14 @@ static unsigned char mincore_page(struct vm_area_struct * vma, */ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pages) { - unsigned long i, nr, pgoff; + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *ptep; + spinlock_t *ptl; + unsigned long nr; + int i; + pgoff_t pgoff; struct vm_area_struct *vma = find_vma(current->mm, addr); /* @@ -55,32 +73,119 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag if (!vma || addr < vma->vm_start) return -ENOMEM; +#ifdef CONFIG_HUGETLB_PAGE + if (is_vm_hugetlb_page(vma)) { + struct hstate *h; + unsigned long nr_huge; + unsigned char present; + + i = 0; + nr = min(pages, (vma->vm_end - addr) >> PAGE_SHIFT); + h = hstate_vma(vma); + nr_huge = ((addr + pages * PAGE_SIZE - 1) >> huge_page_shift(h)) + - (addr >> huge_page_shift(h)) + 1; + nr_huge = min(nr_huge, + (vma->vm_end - addr) >> huge_page_shift(h)); + while (1) { + /* hugepage always in RAM for now, + * but generally it needs to be check */ + ptep = huge_pte_offset(current->mm, + addr & huge_page_mask(h)); + present = !!(ptep && + !huge_pte_none(huge_ptep_get(ptep))); + while (1) { + vec[i++] = present; + addr += PAGE_SIZE; + /* reach buffer limit */ + if (i == nr) + return nr; + /* check hugepage border */ + if (!((addr & ~huge_page_mask(h)) + >> PAGE_SHIFT)) + break; + } + } + return nr; + } +#endif + /* - * Ok, got it. But check whether it's a segment we support - * mincore() on. Right now, we don't do any anonymous mappings. - * - * FIXME: This is just stupid. And returning ENOMEM is - * stupid too. We should just look at the page tables. But - * this is what we've traditionally done, so we'll just - * continue doing it. + * Calculate how many pages there are left in the last level of the + * PTE array for our address. */ - if (!vma->vm_file) - return -ENOMEM; + nr = PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1)); + + /* + * Don't overrun this vma + */ + nr = min(nr, (vma->vm_end - addr) >> PAGE_SHIFT); /* - * Calculate how many pages there are left in the vma, and - * what the pgoff is for our address. + * Don't return more than the caller asked for */ - nr = (vma->vm_end - addr) >> PAGE_SHIFT; - if (nr > pages) - nr = pages; + nr = min(nr, pages); - pgoff = (addr - vma->vm_start) >> PAGE_SHIFT; - pgoff += vma->vm_pgoff; + pgd = pgd_offset(vma->vm_mm, addr); + if (pgd_none_or_clear_bad(pgd)) + goto none_mapped; + pud = pud_offset(pgd, addr); + if (pud_none_or_clear_bad(pud)) + goto none_mapped; + pmd = pmd_offset(pud, addr); + if (pmd_none_or_clear_bad(pmd)) + goto none_mapped; - /* And then we just fill the sucker in.. */ - for (i = 0 ; i < nr; i++, pgoff++) - vec[i] = mincore_page(vma, pgoff); + ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + for (i = 0; i < nr; i++, ptep++, addr += PAGE_SIZE) { + unsigned char present; + pte_t pte = *ptep; + + if (pte_present(pte)) { + present = 1; + + } else if (pte_none(pte)) { + if (vma->vm_file) { + pgoff = linear_page_index(vma, addr); + present = mincore_page(vma->vm_file->f_mapping, + pgoff); + } else + present = 0; + + } else if (pte_file(pte)) { + pgoff = pte_to_pgoff(pte); + present = mincore_page(vma->vm_file->f_mapping, pgoff); + + } else { /* pte is a swap entry */ + swp_entry_t entry = pte_to_swp_entry(pte); + if (is_migration_entry(entry)) { + /* migration entries are always uptodate */ + present = 1; + } else { +#ifdef CONFIG_SWAP + pgoff = entry.val; + present = mincore_page(&swapper_space, pgoff); +#else + WARN_ON(1); + present = 1; +#endif + } + } + + vec[i] = present; + } + pte_unmap_unlock(ptep-1, ptl); + + return nr; + +none_mapped: + if (vma->vm_file) { + pgoff = linear_page_index(vma, addr); + for (i = 0; i < nr; i++, pgoff++) + vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff); + } else { + for (i = 0; i < nr; i++) + vec[i] = 0; + } return nr; } @@ -109,8 +214,8 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag * mapped * -EAGAIN - A kernel resource was temporarily unavailable. */ -asmlinkage long sys_mincore(unsigned long start, size_t len, - unsigned char __user * vec) +SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len, + unsigned char __user *, vec) { long retval; unsigned long pages;