Re: linux-next: Tree for Apr 6 (arch/x86/mm/init_64.c)

[Randy Dunlap]

On 4/6/21 11:32 AM, Randy Dunlap wrote:
> On 4/6/21 5:31 AM, Stephen Rothwell wrote:
>> Hi all,
>>
>> Changes since 20210401:
>>
> 
> on x86_64:
> # CONFIG_SPARSEMEM_VMEMMAP is not set
> 
> 
> gcc (SUSE Linux) 7.5.0
> 
> 
> ../arch/x86/mm/init_64.c: In function 'remove_pmd_table':
> ../arch/x86/mm/init_64.c:1127:8: error: implicit declaration of function 'vmemmap_pmd_is_unused'; did you mean 'vmemmap_pmd_populate'? [-Werror=implicit-function-declaration]
>         vmemmap_pmd_is_unused(addr, next)) {
>         ^~~~~~~~~~~~~~~~~~~~~
>         vmemmap_pmd_populate
> 
> 
> Looks like that compound "if" is too much for gcc 7.5.0 to handle:
> 
> 			} else if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP) &&
> 				   vmemmap_pmd_is_unused(addr, next)) {
> 					free_hugepage_table(pmd_page(*pmd),
> 							    altmap);
> 					spin_lock(&init_mm.page_table_lock);
> 					pmd_clear(pmd);
> 					spin_unlock(&init_mm.page_table_lock);
> 			}
> 
> 

This is what I am using for now:

---
---
 arch/x86/mm/init_64.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- linux-next-20210406.orig/arch/x86/mm/init_64.c
+++ linux-next-20210406/arch/x86/mm/init_64.c
@@ -1123,14 +1123,16 @@ remove_pmd_table(pmd_t *pmd_start, unsig
 				pmd_clear(pmd);
 				spin_unlock(&init_mm.page_table_lock);
 				pages++;
-			} else if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP) &&
-				   vmemmap_pmd_is_unused(addr, next)) {
+			}
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+			else if (vmemmap_pmd_is_unused(addr, next)) {
 					free_hugepage_table(pmd_page(*pmd),
 							    altmap);
 					spin_lock(&init_mm.page_table_lock);
 					pmd_clear(pmd);
 					spin_unlock(&init_mm.page_table_lock);
 			}
+#endif
 
 			continue;
 		}