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authorAdam Litke <agl@us.ibm.com>2007-11-14 16:59:39 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-11-14 18:45:40 -0800
commit2fc39cec6a9b5b41727d3386b780b69422a15152 (patch)
tree4b01dcef394a109ae3ff83189f7386ff3cdb3f61
parentc79fb75e5a514a5a35f22c229042aa29f4237e3a (diff)
hugetlb: debit quota in alloc_huge_page
Now that quota is credited by free_huge_page(), calls to hugetlb_get_quota() seem out of place. The alloc/free API is unbalanced because we handle the hugetlb_put_quota() but expect the caller to open-code hugetlb_get_quota(). Move the get inside alloc_huge_page to clean up this disparity. This patch has been kept apart from the previous patch because of the somewhat dodgy ERR_PTR() use herein. Moving the quota logic means that alloc_huge_page() has two failure modes. Quota failure must result in a SIGBUS while a standard allocation failure is OOM. Unfortunately, ERR_PTR() doesn't like the small positive errnos we have in VM_FAULT_* so they must be negated before they are used. Does anyone take issue with the way I am using PTR_ERR. If so, what are your thoughts on how to clean this up (without needing an if,else if,else block at each alloc_huge_page() callsite)? Signed-off-by: Adam Litke <agl@us.ibm.com> Cc: Ken Chen <kenchen@google.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: David Gibson <hermes@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/hugetlb.c24
1 files changed, 12 insertions, 12 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 3992bd5120e..bc12b0adfa8 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -388,6 +388,10 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
unsigned long addr)
{
struct page *page;
+ struct address_space *mapping = vma->vm_file->f_mapping;
+
+ if (hugetlb_get_quota(mapping))
+ return ERR_PTR(-VM_FAULT_SIGBUS);
if (vma->vm_flags & VM_MAYSHARE)
page = alloc_huge_page_shared(vma, addr);
@@ -395,9 +399,10 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
page = alloc_huge_page_private(vma, addr);
if (page) {
set_page_refcounted(page);
- set_page_private(page, (unsigned long) vma->vm_file->f_mapping);
- }
- return page;
+ set_page_private(page, (unsigned long) mapping);
+ return page;
+ } else
+ return ERR_PTR(-VM_FAULT_OOM);
}
static int __init hugetlb_init(void)
@@ -737,15 +742,13 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
set_huge_ptep_writable(vma, address, ptep);
return 0;
}
- if (hugetlb_get_quota(vma->vm_file->f_mapping))
- return VM_FAULT_SIGBUS;
page_cache_get(old_page);
new_page = alloc_huge_page(vma, address);
- if (!new_page) {
+ if (IS_ERR(new_page)) {
page_cache_release(old_page);
- return VM_FAULT_OOM;
+ return -PTR_ERR(new_page);
}
spin_unlock(&mm->page_table_lock);
@@ -789,12 +792,9 @@ retry:
size = i_size_read(mapping->host) >> HPAGE_SHIFT;
if (idx >= size)
goto out;
- if (hugetlb_get_quota(mapping))
- goto out;
page = alloc_huge_page(vma, address);
- if (!page) {
- hugetlb_put_quota(mapping);
- ret = VM_FAULT_OOM;
+ if (IS_ERR(page)) {
+ ret = -PTR_ERR(page);
goto out;
}
clear_huge_page(page, address);