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>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index c868309..34a7e23 100644 (file)
--- 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));