Subject: Re: linux-next: build failure after merge of the akpm tree

From: John Hubbard <[email-masked]>
Date: Mon, 25 May 2020 11:18:46 -0700

On 2020-05-25 05:17, Stephen Rothwell wrote:
> Hi all,
> 
> After merging the akpm tree, today's linux-next build (x86_64
> allmodconfig) failed like this:
> 
> In file included from include/linux/kernel.h:14,
>                   from mm/gup.c:2:
> mm/gup.c: In function 'internal_get_user_pages_fast':
> mm/gup.c:2732:33: error: 'struct mm_struct' has no member named 'mmap_sem'; did you mean 'mmap_base'?
>   2732 |   might_lock_read(&current->mm->mmap_sem);
>        |                                 ^~~~~~~~
> 
> Caused by commit
> 
>    64fe66e8a95e ("mmap locking API: rename mmap_sem to mmap_lock")
> 
> fron the akpm tree interacting with commit
> 
>    b1fc8b5ddb4e ("mm/gup: might_lock_read(mmap_sem) in get_user_pages_fast()")
> 
> from the akpm-current tree.
> 
> I added the following patch for today.
> 
> From: Stephen Rothwell <[email-masked]>
> Date: Mon, 25 May 2020 22:11:51 +1000
> Subject: [PATCH] mm/gup: update for mmap_sem rename
> 
> Signed-off-by: Stephen Rothwell <[email-masked]>
> ---
>   mm/gup.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/gup.c b/mm/gup.c
> index 8977e5fe9843..f4bca3de0b4b 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -2729,7 +2729,7 @@ static int internal_get_user_pages_fast(unsigned long start, int nr_pages,
>   		return -EINVAL;
>   
>   	if (!(gup_flags & FOLL_FAST_ONLY))
> -		might_lock_read(&current->mm->mmap_sem);
> +		might_lock_read(&current->mm->mmap_lock);
>   
>   	start = untagged_addr(start) & PAGE_MASK;
>   	addr = start;
> 

Yes, looks good. And in fact, Andrew has the same fix-up in the mmotm branch of
linux-next.git, as

     commit a76c281a8ddd ("mmap-locking-api-rename-mmap_sem-to-mmap_lock-fix").

thanks,
-- 
John Hubbard
NVIDIA