hugetlb: allow bulk updating in hugetlb_*_quota()

Add a second parameter 'delta' to hugetlb_get_quota and hugetlb_put_quota to
allow bulk updating of the sbinfo->free_blocks counter.  This will be used by
the next patch in the series.
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>

fs/hugetlbfs/inode.c

@@ -858,15 +858,15 @@ hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 	return -ENOMEM;
 }
 
-int hugetlb_get_quota(struct address_space *mapping)
+int hugetlb_get_quota(struct address_space *mapping, long delta)
 {
 	int ret = 0;
 	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 
 	if (sbinfo->free_blocks > -1) {
 		spin_lock(&sbinfo->stat_lock);
-		if (sbinfo->free_blocks > 0)
-			sbinfo->free_blocks--;
+		if (sbinfo->free_blocks - delta >= 0)
+			sbinfo->free_blocks -= delta;
 		else
 			ret = -ENOMEM;
 		spin_unlock(&sbinfo->stat_lock);
@@ -875,13 +875,13 @@ int hugetlb_get_quota(struct address_space *mapping)
 	return ret;
 }
 
-void hugetlb_put_quota(struct address_space *mapping)
+void hugetlb_put_quota(struct address_space *mapping, long delta)
 {
 	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
 
 	if (sbinfo->free_blocks > -1) {
 		spin_lock(&sbinfo->stat_lock);
-		sbinfo->free_blocks++;
+		sbinfo->free_blocks += delta;
 		spin_unlock(&sbinfo->stat_lock);
 	}
 }

include/linux/hugetlb.h

@@ -165,8 +165,8 @@ static inline struct hugetlbfs_sb_info *HUGETLBFS_SB(struct super_block *sb)
 extern const struct file_operations hugetlbfs_file_operations;
 extern struct vm_operations_struct hugetlb_vm_ops;
 struct file *hugetlb_file_setup(const char *name, size_t);
-int hugetlb_get_quota(struct address_space *mapping);
-void hugetlb_put_quota(struct address_space *mapping);
+int hugetlb_get_quota(struct address_space *mapping, long delta);
+void hugetlb_put_quota(struct address_space *mapping, long delta);
 
 static inline int is_file_hugepages(struct file *file)
 {

mm/hugetlb.c

@@ -132,7 +132,7 @@ static void free_huge_page(struct page *page)
 	}
 	spin_unlock(&hugetlb_lock);
 	if (mapping)
-		hugetlb_put_quota(mapping);
+		hugetlb_put_quota(mapping, 1);
 	set_page_private(page, 0);
 }
 
@@ -390,7 +390,7 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma,
 	struct page *page;
 	struct address_space *mapping = vma->vm_file->f_mapping;
 
-	if (hugetlb_get_quota(mapping))
+	if (hugetlb_get_quota(mapping, 1))
 		return ERR_PTR(-VM_FAULT_SIGBUS);
 
 	if (vma->vm_flags & VM_MAYSHARE)