diff options
| -rw-r--r-- | include/linux/highmem.h | 19 | ||||
| -rw-r--r-- | mm/highmem.c | 52 |
2 files changed, 67 insertions, 4 deletions
diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 14e6202ce47f..8e21fe82b3a3 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -284,13 +284,22 @@ static inline void clear_highpage(struct page *page) kunmap_atomic(kaddr); } +/* + * If we pass in a base or tail page, we can zero up to PAGE_SIZE. + * If we pass in a head page, we can zero up to the size of the compound page. + */ +#if defined(CONFIG_HIGHMEM) && defined(CONFIG_TRANSPARENT_HUGEPAGE) +void zero_user_segments(struct page *page, unsigned start1, unsigned end1, + unsigned start2, unsigned end2); +#else /* !HIGHMEM || !TRANSPARENT_HUGEPAGE */ static inline void zero_user_segments(struct page *page, - unsigned start1, unsigned end1, - unsigned start2, unsigned end2) + unsigned start1, unsigned end1, + unsigned start2, unsigned end2) { void *kaddr = kmap_atomic(page); + unsigned int i; - BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE); + BUG_ON(end1 > page_size(page) || end2 > page_size(page)); if (end1 > start1) memset(kaddr + start1, 0, end1 - start1); @@ -299,8 +308,10 @@ static inline void zero_user_segments(struct page *page, memset(kaddr + start2, 0, end2 - start2); kunmap_atomic(kaddr); - flush_dcache_page(page); + for (i = 0; i < compound_nr(page); i++) + flush_dcache_page(page + i); } +#endif /* !HIGHMEM || !TRANSPARENT_HUGEPAGE */ static inline void zero_user_segment(struct page *page, unsigned start, unsigned end) diff --git a/mm/highmem.c b/mm/highmem.c index 1352a27951e3..0ee87a9e0cbf 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -369,6 +369,58 @@ void kunmap_high(struct page *page) } EXPORT_SYMBOL(kunmap_high); + +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +void zero_user_segments(struct page *page, unsigned start1, unsigned end1, + unsigned start2, unsigned end2) +{ + unsigned int i; + + BUG_ON(end1 > page_size(page) || end2 > page_size(page)); + + for (i = 0; i < compound_nr(page); i++) { + void *kaddr = NULL; + + if (start1 < PAGE_SIZE || start2 < PAGE_SIZE) + kaddr = kmap_atomic(page + i); + + if (start1 >= PAGE_SIZE) { + start1 -= PAGE_SIZE; + end1 -= PAGE_SIZE; + } else { + unsigned this_end = min_t(unsigned, end1, PAGE_SIZE); + + if (end1 > start1) + memset(kaddr + start1, 0, this_end - start1); + end1 -= this_end; + start1 = 0; + } + + if (start2 >= PAGE_SIZE) { + start2 -= PAGE_SIZE; + end2 -= PAGE_SIZE; + } else { + unsigned this_end = min_t(unsigned, end2, PAGE_SIZE); + + if (end2 > start2) + memset(kaddr + start2, 0, this_end - start2); + end2 -= this_end; + start2 = 0; + } + + if (kaddr) { + kunmap_atomic(kaddr); + flush_dcache_page(page + i); + } + + if (!end1 && !end2) + break; + } + + BUG_ON((start1 | start2 | end1 | end2) != 0); +} +EXPORT_SYMBOL(zero_user_segments); +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #endif /* CONFIG_HIGHMEM */ #if defined(HASHED_PAGE_VIRTUAL) |