From: Yves-Alexis Perez <corsac@debian.org>
Date: Sun, 7 Jan 2018 13:50:46 +0000 (+0100)
Subject: Revert "mm, hugetlbfs: introduce ->split() to vm_operations_struct"
X-Git-Tag: archive/raspbian/4.9.80-2+rpi1~8^2~8
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success/%22http:/www.example.com/cgi/success?a=commitdiff_plain;h=f5be2369bd293d5ca289a5cc16d22cbd05d2ccc7;p=linux-4.9.git

Revert "mm, hugetlbfs: introduce ->split() to vm_operations_struct"

This reverts commit cebe139e5712d6925a9b70f3769df6818b6c14dd, which was
commit 31383c6865a578834dd953d9dbc88e6b19fe3997 upstream. It introduces
an ABI break and the depending commits are not in 4.9.


Gbp-Pq: Topic debian
Gbp-Pq: Name revert-mm-hugetlbfs-introduce-split-to-vm_operations.patch
---

diff --git a/include/linux/mm.h b/include/linux/mm.h
index d8946909a756..d61d957b81ce 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -348,7 +348,6 @@ struct fault_env {
 struct vm_operations_struct {
 	void (*open)(struct vm_area_struct * area);
 	void (*close)(struct vm_area_struct * area);
-	int (*split)(struct vm_area_struct * area, unsigned long addr);
 	int (*mremap)(struct vm_area_struct * area);
 	int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
 	int (*pmd_fault)(struct vm_area_struct *, unsigned long address,
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 6ff65c405243..65c36acf8a6b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3135,13 +3135,6 @@ static void hugetlb_vm_op_close(struct vm_area_struct *vma)
 	}
 }
 
-static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
-{
-	if (addr & ~(huge_page_mask(hstate_vma(vma))))
-		return -EINVAL;
-	return 0;
-}
-
 /*
  * We cannot handle pagefaults against hugetlb pages at all.  They cause
  * handle_mm_fault() to try to instantiate regular-sized pages in the
@@ -3158,7 +3151,6 @@ const struct vm_operations_struct hugetlb_vm_ops = {
 	.fault = hugetlb_vm_op_fault,
 	.open = hugetlb_vm_op_open,
 	.close = hugetlb_vm_op_close,
-	.split = hugetlb_vm_op_split,
 };
 
 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
diff --git a/mm/mmap.c b/mm/mmap.c
index 1cb67646307c..f4658f7cdb47 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2546,11 +2546,9 @@ static int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
 	struct vm_area_struct *new;
 	int err;
 
-	if (vma->vm_ops && vma->vm_ops->split) {
-		err = vma->vm_ops->split(vma, addr);
-		if (err)
-			return err;
-	}
+	if (is_vm_hugetlb_page(vma) && (addr &
+					~(huge_page_mask(hstate_vma(vma)))))
+		return -EINVAL;
 
 	new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
 	if (!new)