diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/filemap.c | 32 | ||||
| -rw-r--r-- | mm/mincore.c | 22 |
2 files changed, 39 insertions, 15 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 00414849a86..d1060b8d3cd 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2079,21 +2079,27 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, /* Limit the size of the copy to the caller's write size */ bytes = min(bytes, count); - /* - * Limit the size of the copy to that of the current segment, - * because fault_in_pages_readable() doesn't know how to walk - * segments. + /* We only need to worry about prefaulting when writes are from + * user-space. NFSd uses vfs_writev with several non-aligned + * segments in the vector, and limiting to one segment a time is + * a noticeable performance for re-write */ - bytes = min(bytes, cur_iov->iov_len - iov_base); - - /* - * Bring in the user page that we will copy from _first_. - * Otherwise there's a nasty deadlock on copying from the - * same page as we're writing to, without it being marked - * up-to-date. - */ - fault_in_pages_readable(buf, bytes); + if (!segment_eq(get_fs(), KERNEL_DS)) { + /* + * Limit the size of the copy to that of the current + * segment, because fault_in_pages_readable() doesn't + * know how to walk segments. + */ + bytes = min(bytes, cur_iov->iov_len - iov_base); + /* + * Bring in the user page that we will copy from + * _first_. Otherwise there's a nasty deadlock on + * copying from the same page as we're writing to, + * without it being marked up-to-date. + */ + fault_in_pages_readable(buf, bytes); + } page = __grab_cache_page(mapping,index,&cached_page,&lru_pvec); if (!page) { status = -ENOMEM; diff --git a/mm/mincore.c b/mm/mincore.c index 95c5f49f0a1..5efe0ded69b 100644 --- a/mm/mincore.c +++ b/mm/mincore.c @@ -77,8 +77,16 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag * PTE array for our address. */ nr = PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1)); - if (nr > pages) - nr = pages; + + /* + * Don't overrun this vma + */ + nr = min(nr, (vma->vm_end - addr) >> PAGE_SHIFT); + + /* + * 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)) @@ -116,10 +124,17 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag /* 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); @@ -130,6 +145,9 @@ none_mapped: 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; |