hugetlb: don't use ERR_PTR with VM_FAULT* values

The current use of VM_FAULT_* codes with ERR_PTR requires us to ensure
VM_FAULT_* values will not exceed MAX_ERRNO value.  Decouple the
VM_FAULT_* values from MAX_ERRNO.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Hillf Danton <dhillf@gmail.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 13 insertions, 5 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index c86830931cc6..34a7e2375478 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1123,10 +1123,10 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
          */
         chg = vma_needs_reservation(h, vma, addr);
         if (chg < 0)
-                return ERR_PTR(-VM_FAULT_OOM);
+                return ERR_PTR(-ENOMEM);
         if (chg)
                 if (hugepage_subpool_get_pages(spool, chg))
-                        return ERR_PTR(-VM_FAULT_SIGBUS);
+                        return ERR_PTR(-ENOSPC);
 
         spin_lock(&hugetlb_lock);
         page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
@@ -1136,7 +1136,7 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
                 page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
                 if (!page) {
                         hugepage_subpool_put_pages(spool, chg);
-                        return ERR_PTR(-VM_FAULT_SIGBUS);
+                        return ERR_PTR(-ENOSPC);
                 }
         }
 
@@ -2496,6 +2496,7 @@ retry_avoidcopy:
         new_page = alloc_huge_page(vma, address, outside_reserve);
 
         if (IS_ERR(new_page)) {
+                long err = PTR_ERR(new_page);
                 page_cache_release(old_page);
 
                 /*
@@ -2524,7 +2525,10 @@ retry_avoidcopy:
 
                 /* Caller expects lock to be held */
                 spin_lock(&mm->page_table_lock);
-                return -PTR_ERR(new_page);
+                if (err == -ENOMEM)
+                        return VM_FAULT_OOM;
+                else
+                        return VM_FAULT_SIGBUS;
         }
 
         /*
@@ -2642,7 +2646,11 @@ retry:
                         goto out;
                 page = alloc_huge_page(vma, address, 0);
                 if (IS_ERR(page)) {
-                        ret = -PTR_ERR(page);
+                        ret = PTR_ERR(page);
+                        if (ret == -ENOMEM)
+                                ret = VM_FAULT_OOM;
+                        else
+                                ret = VM_FAULT_SIGBUS;
                         goto out;
                 }
                 clear_huge_page(page, address, pages_per_huge_page(h));