Currently hugetlb_vma_lock_alloc doesn't return anything, as there is no
need: if it fails, PMD sharing won't be enabled. However, HGM requires
that the VMA lock exists, so we need to verify that
hugetlb_vma_lock_alloc actually succeeded. If hugetlb_vma_lock_alloc
fails, then we can pass that up to the caller that is attempting to
enable HGM.
Signed-off-by: James Houghton <jthoughton@xxxxxxxxxx>
---
mm/hugetlb.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 52cec5b0789e..dc82256b89dd 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -92,7 +92,7 @@ struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
/* Forward declaration */
static int hugetlb_acct_memory(struct hstate *h, long delta);
static void hugetlb_vma_lock_free(struct vm_area_struct *vma);
-static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma);
+static int hugetlb_vma_lock_alloc(struct vm_area_struct *vma);
static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma);
static inline bool subpool_is_free(struct hugepage_subpool *spool)
@@ -7001,17 +7001,17 @@ static void hugetlb_vma_lock_free(struct vm_area_struct *vma)
}
}
-static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma)
+static int hugetlb_vma_lock_alloc(struct vm_area_struct *vma)
{
struct hugetlb_vma_lock *vma_lock;
/* Only establish in (flags) sharable vmas */
if (!vma || !(vma->vm_flags & VM_MAYSHARE))
- return;
+ return -EINVAL;
- /* Should never get here with non-NULL vm_private_data */
+ /* We've already allocated the lock. */
if (vma->vm_private_data)
- return;
+ return 0;
vma_lock = kmalloc(sizeof(*vma_lock), GFP_KERNEL);
if (!vma_lock) {
@@ -7026,13 +7026,14 @@ static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma)
* allocation failure.
*/
pr_warn_once("HugeTLB: unable to allocate vma specific lock\n");
- return;
+ return -ENOMEM;
}
kref_init(&vma_lock->refs);
init_rwsem(&vma_lock->rw_sema);
vma_lock->vma = vma;
vma->vm_private_data = vma_lock;
+ return 0;
}
/*
@@ -7160,8 +7161,9 @@ static void hugetlb_vma_lock_free(struct vm_area_struct *vma)
{
}
-static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma)
+static int hugetlb_vma_lock_alloc(struct vm_area_struct *vma)
{
+ return 0;
}
pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
--
2.38.0.135.g90850a2211-goog
