From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> For now we still write/read at most PAGE_CACHE_SIZE bytes a time. This implementation doesn't cover address spaces with backing store. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> --- mm/filemap.c | 35 ++++++++++++++++++++++++++++++----- 1 file changed, 30 insertions(+), 5 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index bdedb1b..79ba9cd 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1165,12 +1165,23 @@ find_page: if (unlikely(page == NULL)) goto no_cached_page; } + if (PageTransTail(page)) { + page_cache_release(page); + page = find_get_page(mapping, + index & ~HPAGE_CACHE_INDEX_MASK); + if (!PageTransHuge(page)) { + page_cache_release(page); + goto find_page; + } + } if (PageReadahead(page)) { + BUG_ON(PageTransHuge(page)); page_cache_async_readahead(mapping, ra, filp, page, index, last_index - index); } if (!PageUptodate(page)) { + BUG_ON(PageTransHuge(page)); if (inode->i_blkbits == PAGE_CACHE_SHIFT || !mapping->a_ops->is_partially_uptodate) goto page_not_up_to_date; @@ -1212,18 +1223,25 @@ page_ok: } nr = nr - offset; + /* Recalculate offset in page if we've got a huge page */ + if (PageTransHuge(page)) { + offset = (((loff_t)index << PAGE_CACHE_SHIFT) + offset); + offset &= ~HPAGE_PMD_MASK; + } + /* If users can be writing to this page using arbitrary * virtual addresses, take care about potential aliasing * before reading the page on the kernel side. */ if (mapping_writably_mapped(mapping)) - flush_dcache_page(page); + flush_dcache_page(page + (offset >> PAGE_CACHE_SHIFT)); /* * When a sequential read accesses a page several times, * only mark it as accessed the first time. */ - if (prev_index != index || offset != prev_offset) + if (prev_index != index || + (offset & ~PAGE_CACHE_MASK) != prev_offset) mark_page_accessed(page); prev_index = index; @@ -1238,8 +1256,9 @@ page_ok: * "pos" here (the actor routine has to update the user buffer * pointers and the remaining count). */ - ret = file_read_actor(desc, page, offset, nr); - offset += ret; + ret = file_read_actor(desc, page + (offset >> PAGE_CACHE_SHIFT), + offset & ~PAGE_CACHE_MASK, nr); + offset = (offset & ~PAGE_CACHE_MASK) + ret; index += offset >> PAGE_CACHE_SHIFT; offset &= ~PAGE_CACHE_MASK; prev_offset = offset; @@ -2440,8 +2459,13 @@ again: if (mapping_writably_mapped(mapping)) flush_dcache_page(page); + if (PageTransHuge(page)) + offset = pos & ~HPAGE_PMD_MASK; + pagefault_disable(); - copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); + copied = iov_iter_copy_from_user_atomic( + page + (offset >> PAGE_CACHE_SHIFT), + i, offset & ~PAGE_CACHE_MASK, bytes); pagefault_enable(); flush_dcache_page(page); @@ -2464,6 +2488,7 @@ again: * because not all segments in the iov can be copied at * once without a pagefault. */ + offset = pos & ~PAGE_CACHE_MASK; bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset, iov_iter_single_seg_count(i)); goto again; -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html