[PATCH AUTOSEL 4.19 032/244] arm64: Fix compiler warning from pte_unmap() with -Wunused-but-set-variable

Sasha Levin
2019-05-22T19:47:05Z

From: Qian Cai <cai@lca.pw>

[ Upstream commit 74dd022f9e6260c3b5b8d15901d27ebcc5f21eda ]

When building with -Wunused-but-set-variable, the compiler shouts about
a number of pte_unmap() users, since this expands to an empty macro on
arm64:

| mm/gup.c: In function 'gup_pte_range':
| mm/gup.c:1727:16: warning: variable 'ptem' set but not used
| [-Wunused-but-set-variable]
| mm/gup.c: At top level:
| mm/memory.c: In function 'copy_pte_range':
| mm/memory.c:821:24: warning: variable 'orig_dst_pte' set but not used
| [-Wunused-but-set-variable]
| mm/memory.c:821:9: warning: variable 'orig_src_pte' set but not used
| [-Wunused-but-set-variable]
| mm/swap_state.c: In function 'swap_ra_info':
| mm/swap_state.c:641:15: warning: variable 'orig_pte' set but not used
| [-Wunused-but-set-variable]
| mm/madvise.c: In function 'madvise_free_pte_range':
| mm/madvise.c:318:9: warning: variable 'orig_pte' set but not used
| [-Wunused-but-set-variable]

Rewrite pte_unmap() as a static inline function, which silences the
warnings.

Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm64/include/asm/pgtable.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 1bdeca8918a68..ea423db393644 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -444,6 +444,8 @@ static inline phys_addr_t pmd_page_paddr(pmd_t pmd)
return __pmd_to_phys(pmd);
}

+static inline void pte_unmap(pte_t *pte) { }
+
/* Find an entry in the third-level page table. */
#define pte_index(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))

@@ -452,7 +454,6 @@ static inline phys_addr_t pmd_page_paddr(pmd_t pmd)

#define pte_offset_map(dir,addr) pte_offset_kernel((dir), (addr))
#define pte_offset_map_nested(dir,addr) pte_offset_kernel((dir), (addr))
-#define pte_unmap(pte) do { } while (0)
#define pte_unmap_nested(pte) do { } while (0)

#define pte_set_fixmap(addr) ((pte_t *)set_fixmap_offset(FIX_PTE, addr))
--
2.20.1