+ smaps-fix-defined-but-not-used-smaps_shmem_walk_ops.patch added to mm-unstable branch

+ smaps-fix-defined-but-not-used-smaps_shmem_walk_ops.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: smaps: fix defined but not used smaps_shmem_walk_ops
has been added to the -mm mm-unstable branch.  Its filename is
     smaps-fix-defined-but-not-used-smaps_shmem_walk_ops.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/smaps-fix-defined-but-not-used-smaps_shmem_walk_ops.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Steven Price <steven.price@arm.com>
Subject: smaps: fix defined but not used smaps_shmem_walk_ops
Date: Wed, 5 Apr 2023 11:38:19 +0100

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: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/proc/task_mmu.c       |    3 +--
 include/linux/shmem_fs.h |    7 +++++++
 2 files changed, 8 insertions(+), 2 deletions(-)

--- a/fs/proc/task_mmu.c~smaps-fix-defined-but-not-used-smaps_shmem_walk_ops
+++ a/fs/proc/task_mmu.c
@@ -782,7 +782,6 @@ static void smap_gather_stats(struct vm_
 	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_
 			ops = &smaps_shmem_walk_ops;
 		}
 	}
-#endif
+
 	/* mmap_lock is held in m_start */
 	if (!start)
 		walk_page_vma(vma, ops, mss);
--- a/include/linux/shmem_fs.h~smaps-fix-defined-but-not-used-smaps_shmem_walk_ops
+++ a/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);
 
_

Patches currently in -mm which might be from steven.price@arm.com are

smaps-fix-defined-but-not-used-smaps_shmem_walk_ops.patch