linux-kernel - [PATCH 25/28] mmap: Remove __do_munmap() in favour of do_mas

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Message-Id: <20201210170402.3468568-26-Liam.Howlett@Oracle.com>
Date:   Thu, 10 Dec 2020 12:03:59 -0500
From:   "Liam R. Howlett" <Liam.Howlett@...cle.com>
To:     maple-tree@...ts.infradead.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Cc:     Andrew Morton <akpm@...gle.com>, Song Liu <songliubraving@...com>,
        Davidlohr Bueso <dave@...olabs.net>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Matthew Wilcox <willy@...radead.org>,
        Jerome Glisse <jglisse@...hat.com>,
        David Rientjes <rientjes@...gle.com>,
        Axel Rasmussen <axelrasmussen@...gle.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Vlastimil Babka <vbabka@...e.cz>
Subject: [PATCH 25/28] mmap: Remove __do_munmap() in favour of do_mas_munmap()

Export new interface and use it in place of old interface.

Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
---
 include/linux/mm.h |  4 ++--
 mm/mmap.c          | 16 ++++------------
 mm/mremap.c        |  7 ++++---
 3 files changed, 10 insertions(+), 17 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 93166e22c988f..9f88e2b269406 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2573,8 +2573,8 @@ extern unsigned long mmap_region(struct file *file, unsigned long addr,
 extern unsigned long do_mmap(struct file *file, unsigned long addr,
 	unsigned long len, unsigned long prot, unsigned long flags,
 	unsigned long pgoff, unsigned long *populate, struct list_head *uf);
-extern int __do_munmap(struct mm_struct *, unsigned long, size_t,
-		       struct list_head *uf, bool downgrade);
+extern int do_mas_munmap(struct ma_state *mas, struct mm_struct *mm,
+	 unsigned long start, size_t len, struct list_head *uf, bool downgrade);
 extern int do_munmap(struct mm_struct *, unsigned long, size_t,
 		     struct list_head *uf);
 extern int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int behavior);
diff --git a/mm/mmap.c b/mm/mmap.c
index 48ab40a90428b..36a6b03193eb3 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2543,13 +2543,6 @@ int do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma,
 	return downgrade ? 1 : 0;
 }
 
-int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
-		struct list_head *uf, bool downgrade)
-{
-	MA_STATE(mas, &mm->mm_mt, start, start);
-	return do_mas_munmap(&mas, mm, start, len, uf, downgrade);
-}
-
 /*
  * do_mas_munmap() - munmap a given range.
  * @mas: The maple state
@@ -2598,7 +2591,8 @@ int do_mas_munmap(struct ma_state *mas, struct mm_struct *mm,
 int do_munmap(struct mm_struct *mm, unsigned long start, size_t len,
 	      struct list_head *uf)
 {
-	return __do_munmap(mm, start, len, uf, false);
+	MA_STATE(mas, &mm->mm_mt, start, start);
+	return do_mas_munmap(&mas, mm, start, len, uf, false);
 }
 
 unsigned long mmap_region(struct file *file, unsigned long addr,
@@ -2846,11 +2840,12 @@ static int __vm_munmap(unsigned long start, size_t len, bool downgrade)
 	int ret;
 	struct mm_struct *mm = current->mm;
 	LIST_HEAD(uf);
+	MA_STATE(mas, &mm->mm_mt, start, start);
 
 	if (mmap_write_lock_killable(mm))
 		return -EINTR;
 
-	ret = __do_munmap(mm, start, len, &uf, downgrade);
+	ret = do_mas_munmap(&mas, mm, start, len, &uf, downgrade);
 	/*
 	 * Returning 1 indicates mmap_lock is downgraded.
 	 * But 1 is not legal return value of vm_munmap() and munmap(), reset
@@ -3002,9 +2997,6 @@ static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma,
 	arch_unmap(mm, newbrk, oldbrk);
 
 	if (likely(vma->vm_start >= newbrk)) { // remove entire mapping(s)
-		mas_set(mas, newbrk);
-		if (vma->vm_start != newbrk)
-			mas_reset(mas); // cause a re-walk for the first overlap.
 		ret = do_mas_munmap(mas, mm, newbrk, oldbrk-newbrk, uf, true);
 		goto munmap_full_vma;
 	}
diff --git a/mm/mremap.c b/mm/mremap.c
index 138abbae4f758..a7526a8c1fe5a 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -723,14 +723,15 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 	/*
 	 * Always allow a shrinking remap: that just unmaps
 	 * the unnecessary pages..
-	 * __do_munmap does all the needed commit accounting, and
+	 * do_mas_munmap does all the needed commit accounting, and
 	 * downgrades mmap_lock to read if so directed.
 	 */
 	if (old_len >= new_len) {
 		int retval;
+		MA_STATE(mas, &mm->mm_mt, addr + new_len, addr + new_len);
 
-		retval = __do_munmap(mm, addr+new_len, old_len - new_len,
-				  &uf_unmap, true);
+		retval = do_mas_munmap(&mas, mm, addr + new_len,
+				       old_len - new_len, &uf_unmap, true);
 		if (retval < 0 && old_len != new_len) {
 			ret = retval;
 			goto out;
-- 
2.28.0