From: Liam R. Howlett <Liam.Howlett@oracle.com>
Date: Tue, 10 May 2022 02:41:23 +0000 (-0400)
Subject: fs/exec: Remove vma_adjust() call and use mmap and maple tree calls.
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=05cd9537c49abf0bd3a51721d46b373d0378ac2d;p=users%2Fjedix%2Flinux-maple.git

fs/exec: Remove vma_adjust() call and use mmap and maple tree calls.

Remove yet another user of vma_adjust().

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---

diff --git a/fs/exec.c b/fs/exec.c
index b5e3bfd52b53..be67f089a5f6 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -28,6 +28,7 @@
 #include <linux/file.h>
 #include <linux/fdtable.h>
 #include <linux/mm.h>
+#include <linux/maple_tree.h>
 #include <linux/stat.h>
 #include <linux/fcntl.h>
 #include <linux/swap.h>
@@ -687,8 +688,9 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
 	unsigned long new_start = old_start - shift;
 	unsigned long new_end = old_end - shift;
 	VMA_ITERATOR(vmi, mm, new_start);
-	struct vm_area_struct *next;
+	struct vm_area_struct *next, *new_vma;
 	struct mmu_gather tlb;
+	MA_STATE(mas, &mm->mm_mt, new_start, new_start);
 
 	BUG_ON(new_start > new_end);
 
@@ -699,10 +701,12 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
 	if (vma != vma_next(&vmi))
 		return -EFAULT;
 
+	if (mas_preallocate(&mas, vma, GFP_KERNEL))
+		return -ENOMEM;
 	/*
 	 * cover the whole range: [new_start, old_end)
 	 */
-	if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL))
+	if (vma_expand(&mas, vma, new_start, old_end, vma->vm_pgoff, vma))
 		return -ENOMEM;
 
 	/*
@@ -711,7 +715,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
 	 */
 	if (length != move_page_tables(vma, old_start,
 				       vma, new_start, length, false))
-		return -ENOMEM;
+		goto pt_move_failed;
 
 	lru_add_drain();
 	tlb_gather_mmu(&tlb, mm);
@@ -734,12 +738,22 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
 	}
 	tlb_finish_mmu(&tlb);
 
+	if (sub_vma(mm, vma, &new_vma, new_start, new_end))
+		goto sub_vma_failed;
+
 	/*
 	 * Shrink the vma to just the new range.  Always succeeds.
 	 */
-	vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
+	vma_mas_store(new_vma, &mas);
+	vma_mas_szero(&mas, new_end, old_end);
 
 	return 0;
+
+sub_vma_failed:
+pt_move_failed:
+	mas_destroy(&mas);
+
+	return -ENOMEM;
 }
 
 /*
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d0422f62b876..c12afba3e5f9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2645,6 +2645,15 @@ void anon_vma_interval_tree_verify(struct anon_vma_chain *node);
 extern int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin);
 extern int vma_adjust(struct vm_area_struct *vma, unsigned long start,
 	      unsigned long end, pgoff_t pgoff, struct vm_area_struct *expand);
+inline int vma_expand(struct ma_state *mas, struct vm_area_struct *vma,
+		      unsigned long start, unsigned long end, pgoff_t pgoff,
+		      struct vm_area_struct *next);
+inline void vma_mas_szero(struct ma_state *mas, unsigned long start,
+				unsigned long end);
+inline void vma_mas_store(struct vm_area_struct *vma, struct ma_state *mas);
+int sub_vma(struct mm_struct *mm, struct vm_area_struct *vma,
+	struct vm_area_struct **new_vma, unsigned long start, unsigned long end);
+
 extern struct vm_area_struct *vma_merge(struct mm_struct *,
 	struct vm_area_struct *prev, unsigned long addr, unsigned long end,
 	unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
diff --git a/mm/mmap.c b/mm/mmap.c
index d4a0716b926d..a01eec04d4c1 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -507,7 +507,7 @@ void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas)
  * @start: The start address to zero
  * @end: The end address to zero.
  */
-static inline void vma_mas_szero(struct ma_state *mas, unsigned long start,
+inline void vma_mas_szero(struct ma_state *mas, unsigned long start,
 				unsigned long end)
 {
 	trace_vma_mas_szero(mas->tree, start, end - 1);