There is a bug in below scene for platform !CONFIG_MMU: 1. create a new file 2. mmap the file and write to it 3. read the file can't get the correct value Because sys_read() > generic_file_aio_read() > simple_readpage() > clear_page() which make the page be zeroed. Add SetPageUptodate() to ramfs_nommu_expand_for_mapping() so that generic_file_aio_read() do not call simple_readpage(). Signed-off-by: Bob Liu <lliubbo@xxxxxxxxx> --- fs/ramfs/file-nommu.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c index fbb0b47..d5378d0 100644 --- a/fs/ramfs/file-nommu.c +++ b/fs/ramfs/file-nommu.c @@ -110,6 +110,7 @@ int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize) /* prevent the page from being discarded on memory pressure */ SetPageDirty(page); + SetPageUptodate(page); unlock_page(page); put_page(page); -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>