On Mon, Apr 03, 2023 at 12:12:55PM +0100, Steven Price wrote:
> When !CONFIG_SHMEM smaps_shmem_walk_ops is defined but not used,
> triggering a compiler warning. Surround the definition with an #ifdef to
> keep the compiler happy.
>
> Fixes: 7b86ac3371b7 ("pagewalk: separate function pointers from iterator data")
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Link: https://lore.kernel.org/oe-kbuild-all/202304031749.UiyJpxzF-lkp@xxxxxxxxx/
> Signed-off-by: Steven Price <steven.price@xxxxxxx>
> ---
> fs/proc/task_mmu.c | 2 ++
> 1 file changed, 2 insertions(+)
I think it would be better to enclose the definition of
shmem_swap_usage() in its header with a stub like shmem_mapping and
remove the ifdef completely. shmem_mapping() is already compile time
false.
#ifdef CONFIG_SHMEM
if (vma->vm_file && shmem_mapping(vma->vm_file->f_mapping)) {
/*
* For shared or readonly shmem mappings we know that all
* swapped out pages belong to the shmem object, and we can
* obtain the swap value much more efficiently. For private
* writable mappings, we might have COW pages that are
* not affected by the parent swapped out pages of the shmem
* object, so we have to distinguish them during the page walk.
* Unless we know that the shmem object (or the part mapped by
* our VMA) has no swapped out pages at all.
*/
unsigned long shmem_swapped = shmem_swap_usage(vma);
if (!start && (!shmem_swapped || (vma->vm_flags & VM_SHARED) ||
!(vma->vm_flags & VM_WRITE))) {
mss->swap += shmem_swapped;
} else {
ops = &smaps_shmem_walk_ops;
}
}
#endif
Jason
