smaps: fix defined but not used smaps_shmem_walk_ops

When !CONFIG_SHMEM smaps_shmem_walk_ops is defined but not used,
triggering a compiler warning.  To avoid the warning remove the #ifdef
around the usage.  This has no effect because shmem_mapping() is a stub
returning false when !CONFIG_SHMEM so the code will be compiled out,
however we now need to also provide a stub for shmem_swap_usage().

Link: https://lkml.kernel.org/r/20230405103819.151246-1-steven.price@arm.com
Fixes: 7b86ac3371b7 ("pagewalk: separate function pointers from iterator data")
Signed-off-by: Steven Price <steven.price@arm.com>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202304031749.UiyJpxzF-lkp@intel.com/
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 6a96e17..cb49479 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -782,7 +782,6 @@ static void smap_gather_stats(struct vm_area_struct *vma,
        if (start >= vma->vm_end)
                return;
 
-#ifdef CONFIG_SHMEM
        if (vma->vm_file && shmem_mapping(vma->vm_file->f_mapping)) {
                /*
                 * For shared or readonly shmem mappings we know that all
@@ -803,7 +802,7 @@ static void smap_gather_stats(struct vm_area_struct *vma,
                        ops = &smaps_shmem_walk_ops;
                }
        }
-#endif
+
        /* mmap_lock is held in m_start */
        if (!start)
                walk_page_vma(vma, ops, mss);

diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 3bb8d21..b9516a9 100644 (file)
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -96,7 +96,14 @@ int shmem_unuse(unsigned int type);
 
 extern bool shmem_is_huge(struct inode *inode, pgoff_t index, bool shmem_huge_force,
                          struct mm_struct *mm, unsigned long vm_flags);
+#ifdef CONFIG_SHMEM
 extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
+#else
+static inline unsigned long shmem_swap_usage(struct vm_area_struct *vma)
+{
+       return 0;
+}
+#endif
 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
                                                pgoff_t start, pgoff_t end);