X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=mm%2Fmincore.c;h=5178800bc1294f6649651f5cb2d7ee9a6e183495;hb=f81db8200d1aaf45069399e7525c442ac3013826;hp=07833dc5829df353b4d3cbab0c8c0af668b4f7d7;hpb=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2;p=linux-2.6-omap-h63xx.git diff --git a/mm/mincore.c b/mm/mincore.c index 07833dc5829..5178800bc12 100644 --- a/mm/mincore.c +++ b/mm/mincore.c @@ -1,7 +1,7 @@ /* * linux/mm/mincore.c * - * Copyright (C) 1994-1999 Linus Torvalds + * Copyright (C) 1994-2006 Linus Torvalds */ /* @@ -12,6 +12,8 @@ #include #include #include +#include +#include #include #include @@ -22,14 +24,22 @@ * 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); @@ -38,46 +48,109 @@ static unsigned char mincore_page(struct vm_area_struct * vma, return present; } -static long mincore_vma(struct vm_area_struct * vma, - unsigned long start, unsigned long end, unsigned char __user * vec) +/* + * Do a chunk of "sys_mincore()". We've already checked + * all the arguments, we hold the mmap semaphore: we should + * just return the amount of info we're asked for. + */ +static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pages) { - long error, i, remaining; - unsigned char * tmp; - - error = -ENOMEM; - if (!vma->vm_file) - return error; + 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); - start = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; - if (end > vma->vm_end) - end = vma->vm_end; - end = ((end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; - - error = -EAGAIN; - tmp = (unsigned char *) __get_free_page(GFP_KERNEL); - if (!tmp) - return error; - - /* (end - start) is # of pages, and also # of bytes in "vec */ - remaining = (end - start), + /* + * find_vma() didn't find anything above us, or we're + * in an unmapped hole in the address space: ENOMEM. + */ + if (!vma || addr < vma->vm_start) + return -ENOMEM; - error = 0; - for (i = 0; remaining > 0; remaining -= PAGE_SIZE, i++) { - int j = 0; - long thispiece = (remaining < PAGE_SIZE) ? - remaining : PAGE_SIZE; + /* + * Calculate how many pages there are left in the last level of the + * PTE array for our address. + */ + nr = PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1)); - while (j < thispiece) - tmp[j++] = mincore_page(vma, start++); + /* + * Don't overrun this vma + */ + nr = min(nr, (vma->vm_end - addr) >> PAGE_SHIFT); - if (copy_to_user(vec + PAGE_SIZE * i, tmp, thispiece)) { - error = -EFAULT; - break; + /* + * Don't return more than the caller asked for + */ + nr = min(nr, pages); + + 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; + + 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; } - free_page((unsigned long) tmp); - return error; + return nr; } /* @@ -107,85 +180,50 @@ static long mincore_vma(struct vm_area_struct * vma, asmlinkage long sys_mincore(unsigned long start, size_t len, unsigned char __user * vec) { - int index = 0; - unsigned long end, limit; - struct vm_area_struct * vma; - size_t max; - int unmapped_error = 0; - long error; - - /* check the arguments */ - if (start & ~PAGE_CACHE_MASK) - goto einval; - - if (start < FIRST_USER_PGD_NR * PGDIR_SIZE) - goto enomem; - - limit = TASK_SIZE; - if (start >= limit) - goto enomem; - - if (!len) - return 0; + long retval; + unsigned long pages; + unsigned char *tmp; - max = limit - start; - len = PAGE_CACHE_ALIGN(len); - if (len > max || !len) - goto enomem; - - end = start + len; + /* Check the start address: needs to be page-aligned.. */ + if (start & ~PAGE_CACHE_MASK) + return -EINVAL; - /* check the output buffer whilst holding the lock */ - error = -EFAULT; - down_read(¤t->mm->mmap_sem); + /* ..and we need to be passed a valid user-space range */ + if (!access_ok(VERIFY_READ, (void __user *) start, len)) + return -ENOMEM; - if (!access_ok(VERIFY_WRITE, vec, len >> PAGE_SHIFT)) - goto out; + /* This also avoids any overflows on PAGE_CACHE_ALIGN */ + pages = len >> PAGE_SHIFT; + pages += (len & ~PAGE_MASK) != 0; - /* - * If the interval [start,end) covers some unmapped address - * ranges, just ignore them, but return -ENOMEM at the end. - */ - error = 0; - - vma = find_vma(current->mm, start); - while (vma) { - /* Here start < vma->vm_end. */ - if (start < vma->vm_start) { - unmapped_error = -ENOMEM; - start = vma->vm_start; - } + if (!access_ok(VERIFY_WRITE, vec, pages)) + return -EFAULT; - /* Here vma->vm_start <= start < vma->vm_end. */ - if (end <= vma->vm_end) { - if (start < end) { - error = mincore_vma(vma, start, end, - &vec[index]); - if (error) - goto out; - } - error = unmapped_error; - goto out; + tmp = (void *) __get_free_page(GFP_USER); + if (!tmp) + return -EAGAIN; + + retval = 0; + while (pages) { + /* + * Do at most PAGE_SIZE entries per iteration, due to + * the temporary buffer size. + */ + down_read(¤t->mm->mmap_sem); + retval = do_mincore(start, tmp, min(pages, PAGE_SIZE)); + up_read(¤t->mm->mmap_sem); + + if (retval <= 0) + break; + if (copy_to_user(vec, tmp, retval)) { + retval = -EFAULT; + break; } - - /* Here vma->vm_start <= start < vma->vm_end < end. */ - error = mincore_vma(vma, start, vma->vm_end, &vec[index]); - if (error) - goto out; - index += (vma->vm_end - start) >> PAGE_CACHE_SHIFT; - start = vma->vm_end; - vma = vma->vm_next; + pages -= retval; + vec += retval; + start += retval << PAGE_SHIFT; + retval = 0; } - - /* we found a hole in the area queried if we arrive here */ - error = -ENOMEM; - -out: - up_read(¤t->mm->mmap_sem); - return error; - -einval: - return -EINVAL; -enomem: - return -ENOMEM; + free_page((unsigned long) tmp); + return retval; }