[PATCH v2 1/4] mm/hugetlb: Define hugetlb_falloc structure for hole punch race
From: Mike Kravetz
Date: Tue Oct 20 2015 - 19:53:04 EST
A hugetlb_falloc structure is pointed to by i_private during fallocate
hole punch operations. Page faults check this structure and if they are
in the hole, wait for the operation to finish.
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
include/linux/hugetlb.h | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 685c262..4be35b9 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -42,6 +42,16 @@ struct resv_map {
extern struct resv_map *resv_map_alloc(void);
void resv_map_release(struct kref *ref);
+/*
+ * hugetlb_falloc is used to prevent page faults during falloc hole punch
+ * operations. During hole punch, inode->i_private points to this struct.
+ */
+struct hugetlb_falloc {
+ wait_queue_head_t *waitq; /* Page faults waiting on hole punch */
+ pgoff_t start; /* Start of fallocate hole */
+ pgoff_t end; /* End of fallocate hole */
+};
+
extern spinlock_t hugetlb_lock;
extern int hugetlb_max_hstate __read_mostly;
#define for_each_hstate(h) \
--
2.4.3
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