On Sun, 5 Jun 2011, Al Viro wrote:
> On Sun, Jun 05, 2011 at 12:16:08PM -0700, Hugh Dickins wrote:
>
> > Good find, news to me. Interesting uses of -PTR_ERR()!
>
> You mean, something like the diff below?
Second hunk yes, but first hunk no: there's at least one other place
(hugetlb_reserve_pages) which calls region_chg(), and expects a
conventional -errno return from it; and even if there weren't,
I'd rather not spread these unconventional return values any deeper.
Something more like the one at the bottom I think: okay, it's slightly
tacky to assume the nature of the failure from vma_needs_reservation(),
but we already have two places which do make that assumption.
>
> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> ---
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index f33bb31..3de23f0 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -125,7 +125,7 @@ static long region_chg(struct list_head *head, long f, long t)
> if (&rg->link == head || t < rg->from) {
> nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
> if (!nrg)
> - return -ENOMEM;
> + return -VM_FAULT_OOM;
> nrg->from = f;
> nrg->to = f;
> INIT_LIST_HEAD(&nrg->link);
> @@ -1036,7 +1036,7 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
> return ERR_PTR(chg);
> if (chg)
> if (hugetlb_get_quota(inode->i_mapping, chg))
> - return ERR_PTR(-ENOSPC);
> + return ERR_PTR(-VM_FAULT_SIGBUS);
>
> spin_lock(&hugetlb_lock);
> page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx
---
mm/hugetlb.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- 3.0-rc1/mm/hugetlb.c 2011-05-29 18:42:37.425882575 -0700
+++ linux/mm/hugetlb.c 2011-06-05 13:33:22.795341004 -0700
@@ -1033,10 +1033,10 @@ static struct page *alloc_huge_page(stru
*/
chg = vma_needs_reservation(h, vma, addr);
if (chg < 0)
- return ERR_PTR(chg);
+ return ERR_PTR(-VM_FAULT_OOM);
if (chg)
if (hugetlb_get_quota(inode->i_mapping, chg))
- return ERR_PTR(-ENOSPC);
+ return ERR_PTR(-VM_FAULT_SIGBUS);
spin_lock(&hugetlb_lock);
page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
--
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