Re: [ceph-client:testing 14/39] net/ceph/messenger.c:988:15: error: implicit declaration of function 'iov_iter_get_pages'; did you mean 'iov_iter_get_pages2'?

[Xiubo Li <xiubli@redhat.com>]

On 8/16/22 8:35 AM, kernel test robot wrote:
> tree:   https://github.com/ceph/ceph-client.git testing
> head:   bc940dc5cc27be90472e00ddf510b28b29ffd6ce
> commit: a5cb140194256429d5ce74439e8165390d9380a6 [14/39] libceph: add new iov_iter-based ceph_msg_data_type and ceph_osd_data_type
> config: x86_64-rhel-8.3-kselftests (https://download.01.org/0day-ci/archive/20220816/202208160842.GUNdBYbK-lkp@intel.com/config)
> compiler: gcc-11 (Debian 11.3.0-5) 11.3.0
> reproduce (this is a W=1 build):
>          # https://github.com/ceph/ceph-client/commit/a5cb140194256429d5ce74439e8165390d9380a6
>          git remote add ceph-client https://github.com/ceph/ceph-client.git
>          git fetch --no-tags ceph-client testing
>          git checkout a5cb140194256429d5ce74439e8165390d9380a6
>          # save the config file
>          mkdir build_dir && cp config build_dir/.config
>          make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash net/ceph/
>
> If you fix the issue, kindly add following tag where applicable
> Reported-by: kernel test robot <lkp@intel.com>
>
> All errors (new ones prefixed by >>):
>
>     net/ceph/messenger.c: In function 'ceph_msg_data_iter_next':
>>> net/ceph/messenger.c:988:15: error: implicit declaration of function 'iov_iter_get_pages'; did you mean 'iov_iter_get_pages2'? [-Werror=implicit-function-declaration]
>       988 |         len = iov_iter_get_pages(&cursor->iov_iter, &page, PAGE_SIZE,
>           |               ^~~~~~~~~~~~~~~~~~
>           |               iov_iter_get_pages2
>     cc1: some warnings being treated as errors
>
Thanks for reporting this.

Al has changed it to auto-advance  iterator, the following patch should 
fix it:


diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 945f6d1a9efa..020474cf137c 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -985,25 +985,12 @@ static struct page *ceph_msg_data_iter_next(struct 
ceph_msg_data_cursor *cursor,
         if (cursor->lastlen)
                 iov_iter_revert(&cursor->iov_iter, cursor->lastlen);

-       len = iov_iter_get_pages(&cursor->iov_iter, &page, PAGE_SIZE,
-                                1, page_offset);
+       len = iov_iter_get_pages2(&cursor->iov_iter, &page, PAGE_SIZE,
+                                 1, page_offset);
         BUG_ON(len < 0);

         cursor->lastlen = len;

-       /*
-        * FIXME: Al Viro says that he will soon change iov_iter_get_pages
-        * to auto-advance the iterator. Emulate that here for now.
-        */
-       iov_iter_advance(&cursor->iov_iter, len);
-
-       /*
-        * FIXME: The assumption is that the pages represented by the 
iov_iter
-        *        are pinned, with the references held by the upper-level
-        *        callers, or by virtue of being under writeback. 
Eventually,
-        *        we'll get an iov_iter_get_pages variant that doesn't 
take page
-        *        refs. Until then, just put the page ref.
-        */
         VM_BUG_ON_PAGE(!PageWriteback(page) && page_count(page) < 2, page);
         put_page(page);

-- Xiubo



> vim +988 net/ceph/messenger.c
>
>     977	
>     978	static struct page *ceph_msg_data_iter_next(struct ceph_msg_data_cursor *cursor,
>     979							size_t *page_offset,
>     980							size_t *length)
>     981	{
>     982		struct page *page;
>     983		ssize_t len;
>     984	
>     985		if (cursor->lastlen)
>     986			iov_iter_revert(&cursor->iov_iter, cursor->lastlen);
>     987	
>   > 988		len = iov_iter_get_pages(&cursor->iov_iter, &page, PAGE_SIZE,
>     989					 1, page_offset);
>     990		BUG_ON(len < 0);
>     991	
>     992		cursor->lastlen = len;
>     993	
>     994		/*
>     995		 * FIXME: Al Viro says that he will soon change iov_iter_get_pages
>     996		 * to auto-advance the iterator. Emulate that here for now.
>     997		 */
>     998		iov_iter_advance(&cursor->iov_iter, len);
>     999	
>    1000		/*
>    1001		 * FIXME: The assumption is that the pages represented by the iov_iter
>    1002		 * 	  are pinned, with the references held by the upper-level
>    1003		 * 	  callers, or by virtue of being under writeback. Eventually,
>    1004		 * 	  we'll get an iov_iter_get_pages variant that doesn't take page
>    1005		 * 	  refs. Until then, just put the page ref.
>    1006		 */
>    1007		VM_BUG_ON_PAGE(!PageWriteback(page) && page_count(page) < 2, page);
>    1008		put_page(page);
>    1009	
>    1010		*length = min_t(size_t, len, cursor->resid);
>    1011		return page;
>    1012	}
>    1013	
>